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OIV-MA-AS322-02A Potassium

Type II method

 

1. Principle

Potassium is determined directly in diluted wine by atomic absorption spectrophotometry after the addition of cesium chloride to suppress ionization of potassium.

2. Method

2.1.  Apparatus

Atomic absorption spectrophotometer, equipped with an air - acetylene burner

Potassium hollow cathode lamp

2.2.  Reagents

2.2.1.      Solution containing 1 g of potassium per liter.

Use a standard commercial solution containing 1 g of potassium per liter. This solution may be prepared by dissolving 4.813 g of potassium hydrogen tartrate () in distilled water making up the volume to 1 liter with water.

2.2.2.      Matrix (model) solution:

• citric acid monohydrate :3.5 g
• sucrose 1.5 g
• glycerol 5.0 g
• anhydrous calcium chloride, (Ca) 50 mg
• anhydrous magnesium chloride (Mg) :50 mg
• absolute alcohol 50 mL
• water to 500 mL
  3.       Cesium chloride solution containing 5% cesium:

Dissolve 6.33 g of cesium chloride, CsCl, in 100 mL of distilled water.

2.3.  Procedure

2.3.1.      Preparation of sample

Pipette 2.5 mL of wine (previously diluted 1/10) into a 50 mL volumetric flask, add 1 mL of the cesium chloride solution and make up to the mark with distilled water.

2.3.2.      Calibration

Introduce 5.0 mL of the matrix solution into each one of five of 100mL volumetric flasks and add 0, 2.0, 4.0, 6.0 and 8.0 mL respectively of the 1 g/L potassium solution (previously diluted 1/10).  Add 2 mL of the cesium chloride solution to each flask and make up to 100 mL with distilled water.

The standard solutions contain 0, 2, 4, 6 and 8 mg of potassium per liter respectively and each contains 1 g of cesium per liter.  Keep these solutions in polyethylene bottles.

2.3.3.      Determination

Set the wavelength to 769.9 nm.  Zero the absorbance scale using the zero standard solution (2.3.2).  Aspirate the diluted wine (2.3.1) directly into the spectrophotometer, followed in succession by the standard solutions (2.3.2). Record the absorbance for each solution and repeat.

2.4.  Expression of results

2.4.1.      Method of calculation

Plot a graph showing the variation in absorbance as a function of potassium concentration in the standard solutions.

Record the mean absorbance obtained with diluted wine on this graph and determine its potassium concentration C in milligrams per liter.

The potassium concentration, expressed in milligrams per liter of the wine to the nearest whole number, is F x C, where F is the dilution factor (here 200).

2.4.2.      Repeatability (r):

• r = 35 mg/L.
  3.       Reproducibility (R):
• R = 66 mg/L.
  4.       Other ways of expressing results

In milliequivalents per liter:

• 0.0256 x F x C.

In mg potassium hydrogen tartrate per liter:

• 4.813 x F x C.

OIV-MA-AS322-02B Potassium

Type III method

1. Principle

Potassium is determined directly in diluted wine by flame photometry.

Note: The gravimetric determination of potassium tetraphenylborate precipitated from the solution of the ash of wine is a precise method for the determination of potassium and is described in the annex.

2. Method

2.1.  Apparatus

2.1.1.      Flame photometer supplied with an air‑butane mixture.

2.2.  Reagents

2.2.1.      Reference solution containing 100 mg potassium per liter

• Absolute alcohol 10 mL
• Citric acid 700 mg
• Sucrose 300 mg
• Glycerol 1000 mg
• Sodium chloride, NaCl 50.8 mg
• Anhydrous calcium chloride, Ca 10 mg
• Anhydrous potassium hydrogen tartrate 481.3 mg
• water to 1000 mL

Dissolve the potassium hydrogen tartrate in 500 mL of very hot distilled water, mix this solution with 400 mL of distilled water in which the other chemicals have already been dissolved, and make up to one liter.

2.2.2.      Dilution solution

• Absolute alcohol 10 mL
• Citric acid anhydrous 700 mg
• Sucrose  300 mg
• Glycerol 1000 mg
• Sodium chloride, NaCl 50.8 mg
• Anhydrous calcium chloride, Ca 10 mg
• Anhydrous magnesium chloride, Mg 10 mg
• Tartaric acid 383 mg
• Water to 1000 mL

Preserve the solutions in polyethylene bottles by adding two drops of allyl isothiocyanate (3-isothiocyanato-1-propene; =CHCH₂NCS).

2.3.  Procedure

2.3.1.      Calibration

Place 25, 50, 75 and 100 mL of the reference solution into a set of four 100 mL volumetric flasks and make up to 100 mL with the dilution solution to give solutions containing 25, 50, 75 and 100 mg of potassium per liter respectively.

2.3.2.      Determination

Make measurements at 766 nm. and adjust the 100% transmission using distilled water.  Successively aspirate the standard solutions directly into the burner of the photometer, followed by wine diluted 1/10  with distilled water and note the readings.  If necessary, the wine already diluted ¹/₁₀  may be further diluted with the dilution solution (2.2.2).

2.4.  Expression of results

2.4.1.      Method of calculation

Plot a graph of the variation in percentage transmission as a function of the potassium concentration in the standard solutions. Record the transmission obtained for the sample of diluted wine on this graph and determine the corresponding potassium concentration C.

The potassium concentration in mg potassium per liter to the nearest whole number will be:

• F x C

where F is the dilution factor.

2.4.2.      Repeatability (r):

• r  = 17 mg/L.
  3.       Reproducibility (R)
• R = 66 mg/L.
  4.       Other ways of expressing results:

In milliequivalents per liter: 0.0256 x F x C.

In mg potassium hydrogen tartrate per liter 4.813 x F x C.

OIV-MA-AS322-03A Sodium

Type II method

1. Principle

Sodium is determined directly in the wine by atomic absorption spectrophotometry after the addition of cesium chloride to suppress ionization of sodium.

2. Method

2.1.   Apparatus

Atomic absorption spectrophotometer equipped with an air‑acetylene burner.

Sodium hollow cathode lamp.

2.2.   Reagents

2.2.1. Solution containing 1 g of sodium per liter:

The use of a commercial standard solution containing 1 g of sodium per liter is preferred. 

Alternatively, this solution may be prepared by dissolving 2.542 g of anhydrous sodium chloride (NaCl) in distilled water and making up to a volume of 1 liter.

Keep this solution in a polyethylene bottle.

2.2.2.      Matrix (model) solution:

Citric acid monohydrate, () 3.5 g

Sucrose 1.5 g

Glycerol 5.0 g

Anhydrous calcium chloride (Ca). 50 mg

Anhydrous magnesium chloride, (Mg)  50 mg

Absolute alcohol  50 mL

De‑ionized water to 500 mL

2.2.3. Cesium chloride solution containing 5% cesium

Dissolve 6.330 g of cesium chloride, CsCl, in 100 mL of distilled water.

2.3.   Procedure

2.3.1. Preparation of the sample

Pipette 2.5 mL of wine into a 50 mL volumetric flask, add 1 mL of the cesium chloride solution (2.2.3) and make up to the mark with distilled water.

2.3.2. Calibration

Place 5.0 mL of the matrix solution in each one of five 100 mL volumetric flasks and add 0, 2.5, 5.0, 7.5 and 10 mL respectively of a 1:100 dilution of the 1 g/L sodium solution.  Add 2 mL of the cesium chloride solution (2.2.3) to each flask and make up to 100 mL with distilled water.

The standard solutions prepared in this way contain 0.25, 0.50, 0.75 and 1.00 mg of sodium per liter respectively and each contains 1 g of cesium per liter.  Keep these solutions in polyethylene bottles.

2.3.3. Determination

Set the absorbance wavelength to 589.0 nm.  Zero the absorbance scale using the zero standard solution.  Aspirate the diluted wine (2.3.1) directly into the spectrophotometer, followed in succession by the standard solutions (2.3.2).  Record each absorbance and repeat each measurement.

2.4.   Expression of results

2.4.1. Method of calculation

Plot a graph of measured absorbance versus the sodium concentration in the standard solutions.

Record the absorbance obtained with the diluted wine on this graph and determine its sodium concentration C in milligrams per liter.

The sodium concentration in milligrams per liter of the wine will then be F x C, expressed to the nearest whole number, where F is the dilution factor.

2.4.2. Repeatability (r ):

• r = 1 + 0.024 xi  mg/L.

= concentration of sodium in the sample in mg/L.

2.4.3. Reproducibility (R):

• R = 2.5 + 0.05 xi  mg/L.

 = concentration of sodium in the sample in mg/L.

OIV-MA-AS322-03B Sodium

Type III method

 

1. Principle

Sodium is determined directly in diluted wine (at least 1 mL:10 mL) by flame photometry.

2. Method

2.1.  Apparatus

2.1.1.      Flame photometer supplied with an air‑butane mixture.

2.2.  Reagents

2.2.1.      Reference solution containing 20 mg sodium per liter

Absolute alcohol 10 mL

Citric acid monohydrate () 700 mg

Sucrose  300 mg

Glycerol 1000 mg

Potassium hydrogen tartrate 481.3 mg

Anhydrous calcium chloride, Ca10 mg

Anhydrous magnesium chloride, Mg 10 mg

Dry sodium chloride, NaCl 50.84 mg

Water to 1000 mL

2.2.2.      Dilution solution

Absolute alcohol 10 mL

Citric acid monohydrate () 700 mg

Sucrose 300 mg

Glycerol 1000 mg

Potassium hydrogen tartrate 481.3 mg

Anhydrous calcium chloride, Ca 10 mg

Anhydrous magnesium chloride, Mg 10 mg

Water to 1000 mL

To prepare 2.2.1 and 2.2.2, dissolve the potassium hydrogen tartrate in approximately 500 mL of very hot distilled water, mix with 400 mL of distilled water into which the other chemicals have already been dissolved, and make up to one liter.

Preserve the solutions in polyethylene bottles by adding two drops of allyl isothiocyanate to each.

2.3.  Procedure

2.3.1.      Calibration

Place 5, 10, 15, 20 and 25 mL of the reference solution in each of five 100 mL volumetric flasks and make up to 100 mL with the dilution solution to give solutions containing 1, 2, 3, 4 and 5 mg of sodium per liter respectively.

2.3.2.      Determination

Carry out measurements at 589.0 nm and adjust the 100% transmission using distilled water.  Successively aspirate the standard solutions directly into the photometer, followed by the wine diluted 1:10 with distilled water and note the percentage transmission of each.  If necessary, the wine already diluted 1:10 may be further diluted with dilution solution.

2.4.  Expression of results

2.4.1.      Calculation method

Plot a graph of the percentage transmittance versus sodium concentration of the standard solutions.  Record the transmission obtained for the diluted wine sample on this graph and note the concentration, C, of sodium in the wine.

The sodium concentration in mg of sodium per liter will be:

• F x C

where F is the dilution factor.

2.4.2.      Repeatability (r)

• r = 1.4 mg/L (except for liqueur wine)
• r = 2.0 mg/L for liqueur wine.
  3.       Reproducibility (R)

• R = 4.7 + 0.08 xi  mg/L.
• = sodium concentration in the sample in mg/L.

OIV-MA-AS322-04 Calcium

Type II method

1. Principle

Calcium is determined directly on diluted wine by atomic absorption spectrophotometry after the addition of an ionization suppression agent.

2. Apparatus

2.1.   Atomic absorption spectrophotometer fitted with an air‑acetylene burner.

2.2.   Calcium hollow cathode lamp.

3. Reagents
   1.    Calcium standard solution 1 g/L. Use of a standard commercial calcium solution, 1 g/L, is preferred.

Alternatively this solution may be prepared by dissolving 2.5 g of calcium carbonate, CaC, in sufficient hydrochloric acid (concentrated hydrochloric acid diluted 1:10) to dissolve it completely and making up to one liter with distilled water.

3.2.   Dilute calcium standard solution, 50 mg/L

Note : Store the calcium solutions in polyethylene containers.

3.3.   Dilute lanthanum standard solution, 50 g/L

Dissolve 13.369 g of lanthanum chloride, La in distilled water; add 1 mL, of dilute hydrochloric acid (concentrated hydrochloric acid diluted 1/10) and make up to 100 mL with distilled water.

4. Procedure
   1.    Preparation of sample

Place 1 mL of wine and 2 mL of the lanthanum chloride solution (3.3) in a 20 mL volumetric flask and make up to the mark with distilled water. The diluted wine contains 5 g lanthanum per liter.

Note: For sweet wines, 5 g lanthanum per liter is sufficient provided that the dilution reduces the sugar content to less than 2.5 g/L. For wines with higher concentrations of sugar, the lanthanum concentration should be increased to 10 g/L.

4.2.   Calibration

Place 0, 5, 10, 15 and 20 mL, of dilute standard calcium solution (3.2) respectively into each of five 100 mL volumetric flasks, followed by 10 mL of the lanthanum chloride solution (3.3) and make up to 100 mL with distilled water. The solutions prepared in this way contain 0, 2.5, 5.0, 7.5 and 10 mg of calcium per liter respectively, and each contains 5 g of lanthanum per liter. These solutions should be stored in polyethylene bottles.

4.3.   Determination

Set the absorbance wavelength to 422.7 nm. Zero the absorbance scale using the zero standard (4.2). Aspirate the diluted wine directly into the spectrophotometer, followed in succession by the five standard solutions (4.2) and record the absorbance. Repeat each measurement.

5. Expression of results
   1.    Method of calculation

Plot a graph showing the variation in absorbance as a function of the calcium concentration in the standard solutions.

Record the mean value of the absorbance obtained with the sample of diluted wine on this graph and read its calcium concentration C. The calcium concentration in milligrams per liter of the wine to the nearest whole number is given by: 20 x C.

5.2.   Repeatability (r)

• Concentration<60mg/L: r=2.7mg/L.
• Concentration > 60 mg/L: r = 4 mg/L.
  3.    Reproducibility (R)

• R mg/L = 0.114 - 0.5.

where = concentration in the sample in mg/L.

OIV-MA-AS322-05A Iron

Type IV method

 

1. Principle

After suitable dilution of the wine and removal of alcohol, iron is determined directly by atomic absorption spectrophotometry.

2. Method
   1.   Apparatus
      1.       Rotary evaporator with thermostatically controlled water bath.
      2.       Atomic absorption spectrophotometer equipped with an air‑acetylene burner.
      3.       Iron hollow cathode lamp.

2.2.  Reagents

2.2.1.      Concentrated standard iron solution containing 1 g Fe (III) per liter.

Use a standard commercial solution, 1 g/L. This solution may be prepared by dissolving 8.6341 g of ferric ammonium sulfate, FeNH₄ (SO₄)₂.12H₂0, in distilled water slightly acidified with hydrochloric acid, 1 M, and making up to one liter.

2.2.2.      Dilute standard iron solution containing 100 mg iron per liter.

2.3.  Procedure

2.3.1.      Preparation of sample

Remove the alcohol from the wine by reducing the volume of the sample to half its original size using a rotary evaporator (50 to 60 C). Make up to the original volume with distilled water.

If necessary, dilute prior to analysis with distilled water.

2.3.2.      Calibration

Place 1, 2, 3, 4 and 5 mL of the solution containing 100 mg iron per liter (2.2.2) respectively into each of five 100 mL volumetric flasks and make up to 100 mL with distilled water. The solutions prepared in this way contain 1, 2, 3, 4 and 5 mg of iron per liter respectively. These solutions should be stored in polyethylene bottles.

2.3.3.      Determination

Set the absorption wavelength to 248.3 nm. Zero the absorbance scale using distilled water. Aspirate the diluted sample directly into the spectrophotometer, followed in succession by the five standards (2.3.2). Record the absorbance.  Repeat each measurement.

2.4.  Expression of results

2.4.1.      Method of calculation

Plot a graph giving the variation in absorbance as a function of the iron concentration in the standard solutions.  Record the mean value of the absorbance obtained with the diluted wine sample on this graph and read its iron concentration C.

The iron concentration in milligrams per liter of the wine to one decimal place is given by:

F x C

where F is the dilution factor.

OIV-MA-AS322-05B Iron

Type IV method

 

1. Principle

After digestion in hydrogen peroxide, 30%, the total iron, present as Fe (III) state, is reduced to the Fe (II) and quantified by the formation of a colored orthophenanthroline complex.

2. Method

2.1.  Apparatus

2.1.1.      Kjeldahl flask, 100 mL.

2.1.2.      Spectrophotometer enabling measurements to be made at a wavelength of 508 nm.

 

2.2.  Reagents

2.2.1.      Hydrogen peroxide,, 30% (m/v), solution, iron free.

2.2.2.      Hydrochloric acid, 1 M, iron free.

2.2.3.      Ammonium hydroxide (ρ₂₀ = 0.92 g/mL).

2.2.4.      Pumice stone grains, pretreated with boiling hydrochloric acid diluted 1/2 and washed with distilled water.

2.2.5.      Hydroquinone solution,, 2.5%, acidified with 1 mL concentrated sulfuric acid  ρ₂₀ = 1.84 g/mL) per 100 mL of solution. This solution must be kept in an amber bottle in the refrigerator and discarded at the slightest sign of darkening.

2.2.6.      Sodium sulfite solution, Na₂S0₃, 20%, prepared from neutral anhydrous sodium sulfite.

2.2.7.      ortho-phenanthroline solution, C₁₂H₈N₂, 0.5%, in alcohol, 96% vol.

2.2.8.      Ammonium acetate solution, CH₃COONH₄, 20% (m/v).

2.2.9.      Fe (III) solution containing 1 g of iron per liter. Use of a commercial solution is preferred. Alternatively, a 1000 mg/L Fe (III) solution can be prepared by dissolving 8.6341 g of ferric ammonium sulfate,, in 100 mL of hydrochloric acid, 1 M, and making up the volume to one liter with the hydrochloric acid, 1 M.

2.2.10. Dilute standard iron solution containing 100 milligrams of iron per liter.

2.3.  Procedure

2.3.1.      Digestion

2.3.1.1.                        For wines with sugar content below 50 g/L

Combine 25 mL of the wine, 10 mL of the hydrogen peroxide solution and a few grains of pumice into the 100 mL Kjeldah1 flask.  Concentrate the mixture to a volume of 2 to 3 mL by heating. Allow to cool and add sufficient ammonium hydroxide to make the residue alkaline thus precipitating hydroxides while taking care not to wet the walls of the flask.

After cooling, carefully add hydrochloric acid, to the alkaline liquid to dissolve the precipitated hy­droxides and transfer the resulting solution to a 100 mL volumetric flask. Rinse the Kjeldahl flask with hydrochloric acid, and combined the solutions in the volumetric flask and make up to 100 mL.

2.3.1.2.                        For musts and wines with sugar content above 50 g/L

• If the sugar content is between 50 and 200 g/L, the 25 mL wine sample is treated with 20 mL of hydrogen peroxide solution. Continue as in 2.3.1.1.
• If the sugar content is greater than 200 g/L, the samples of wine or must should be diluted 1/2 or possibly 1/4 before being treated with 20 mL of hydrogen peroxide solution. Continue as in 2.3.1.1.
  2.       Blank experiment

Carry out a blank trial with distilled water using the same volume of hydrogen peroxide solution as the amount used for the mineralization, following the experimental protocol described in 2.3.1.1.

2.3.3.      Determination

Introduce 20 mL of the hydrochloric acid wine digest solution and 20 mL, of the hydrochloric acid solution obtained from the 'blank experiment' into two separate 50 mL volumetric flasks.  Add 2 mL of hydroquinone solution, 2 mL of sulfite solution and 1 mL of ortho-phenanthroline. Allow to stand for 15 minutes, during which time Fe (III) is reduced to Fe (II).  Then add 10 mL of ammonium acetate solution, make each up to 50 mL with distilled water and shake the two volumetric flasks.  Use the solution originating from the blank experiment to zero the absorbance scale at 508 nm and measure the absorbance of the wine solution at the same wavelength.

2.3.4.      Calibration

Place 0.5, 1, 1.5 and 2 mL of the 100 mg of iron per liter solution into each of four 50 mL volumetric flasks, and add 20 mL of distilled water to each.  Carry out the procedure described in 2.3.3 to measure the absor­bance of each of these standard solutions, which contain 50, 100, 150 and 200 micrograms of iron respectively.

2.4.  Expression of results

2.4.1.      Method of calculation

Plot a graph giving the variation in absorbance as a function of the iron concentration in the standard solutions. Record the absorbance of the test solution and read off the iron concentration C in the hydrochloric acid digestion solution, i.e. in 5 mL of the wine being analyzed.

The iron concentration in milligrams per liter of the wine to one decimal place is given by: 200  C

If the wine (or must) has been diluted, the iron concentration in milligrams per liter of the wine to one decimal place is given by: 200  F  C

where F is the dilution factor.

OIV-MA-AS322-06 Copper

Type IV method

1. Principle

The method is based on the use of atomic absorption spectrophotometry.

2. Apparatus

 

2.1.  Platinum dish.

2.2.  Atomic absorption spectrophotometer.

2.3.  Copper hollow cathode lamp.

2.4.  Gas supplies: air‑acetylene or nitrous oxide/acetylene.

3. Reagents

3.1.  Metallic copper.

3.2.  Nitric acid (ρ₂₀ = 1.38 g/mL), 65%.

3.3.  Nitric acid (3.2), diluted 1/2 (v/v) with water.

3.4.  Solution containing 1g of copper per L.

Use of a standard commercial copper solution is preferred. Alternatively this solution may be prepared by weighing 1.000 g of metallic copper and transferring it without loss to a 1000 mL volumetric flask. Add just enough dilute nitric acid to dissolve the metal, add 10 mL of concentrated nitric acid and make up to the mark with double distilled water.

3.5.  Solution containing copper at 100 mg/L

Transfer 10 mL, of the 1 g/L solution 3.4. into a 100 mL volumetric flask, and make up to the mark with double‑distilled water.

3.6.  Double‑distilled water

4. Procedure
   1.   Preparation of sample and determination of copper

Place 20 mL sample in a 100 mL volumetric flask and make up to 100 mL with double‑distilled water. Modify the dilution if necessary to obtain a response within the dynamic range of the detector.

Measure the absorbance at 324.8 nm. Set the zero with double distilled water.

4.2.  Constructing a standard curve

Pipette 0.5, 1 and 2 mL of copper solution into each of three 100 mL volumetric flasks and make to the volume with double distilled water; the solutions contain 0.5, 1 and 2 mg of copper per liter respectively. Measure the absorbance of standard solutions and the sample prepared in and repeat each measurement. Plot a graph showing the variation in absorbance as a function of the copper concentration in the standard solutions.

5. Expression of results

5.1.  Method of calculation

Using the measured absorbance of the samples read off the concentration C in mg/L from the calibration curve.

If F is the dilution factor, the concentration of the copper present is given in milligrams per liter by:

It is quoted to two decimal places.

Notes:

a)      Select a sample dilution appropriate to the sensitivity of the apparatus to be used and the concentration of the copper present in the sample.

b)      Proceed as follows when very low copper concentrations are expected in the sample to be analyzed: Place 100 mL of the sample in a platinum dish and evaporate on a water bath at 100 C until it becomes syrupy. Add 2.5 mL of concentrated nitric acid drop wise, covering the bottom of the dish completely. Carefully ash the residue on an electric hotplate or over a low flame; then place the dish in a muffle furnace set at 500 ± 25C and leave for about one hour. After coo1ing, moisten the ash with 1 mL of concentrated nitric acid while crushing it with a glass rod; allow the mixture to evaporate and ash again as before.  Place the dish in the muffle furnace again for 15 min; repeat the treatment with nitric acid at least three times. Dissolve the ash by adding 1 mL of concentrated nitric acid and 2 mL of double distilled water to the dish and transfer to a 10 mL flask.  Wash the dish three times using 2 mL of double distilled water each time.  Finally, make to volume with double distilled water.  Proceed to analyze the sample as in 4.1 but use 10 mL of solution. Take into account the change in dilution factor when calculating the results.

OIV-MA-AS322-07 Magnesium

Type II method

 

1. Principle

Magnesium is determined directly on diluted wine by atomic absorption spectrophotometry.

2. Apparatus

2.1.  Atomic absorption spectrophotometer fitted with an air‑acetylene burner.

2.2.  Magnesium hollow cathode lamp.

3. Reagents

 

3.1.  Concentrated magnesium standard solution containing 1 g/L

Use of a standard commercial magnesium solution (1 g/L) is preferred.

Alternatively, this solution may be prepared by dissolving 8.3646 g of magnesium chloride, Mg., in distilled water and making up to 1 liter.

3.2.  Dilute magnesium standard solution, 5 mg/L.

Note: Keep the standard magnesium solutions in polyethylene bottles.

4. Procedure

 

4.1.  Preparation of sample

The wine is diluted 1/100 with distilled water.

4.2.  Calibration

Place 5, 10, 15 and 20 mL of the dilute standard magnesium solution into each one of a set of four 100 ml. volumetric flasks and make up to 100 mL with distilled water. The standard solutions prepared in this way contain 0.25, 0.50, 0.75 and 1.0 mg of magnesium per liter respectively. These solutions should be kept in polyethylene bottles.

4.3.  Determination

Set the absorption wavelength to 285 nm. Zero the absorbance scale using distilled water.  Aspirate the diluted wine directly into the spectrophotometer, followed in succession by the standard solutions (4.2).

Record the absorbance of each solution and repeat each measurement.

5. Expression of results

 

5.1.  Method of calculation

Plot a graph showing the variation in absorbance as a function of the magnesium concentration in the standard solutions.

Record the mean value of absorbance with the diluted sample of wine on this graph and read off the magnesium concentration C in milligrams per liter. The magnesium concentration in milligrams per liter of the wine to the nearest whole number is given by:

5.2.  Repeatability (r):

• r = 3 mg/L.
  3.   Reproducibility (R):
• R = 8 mg/L.

OIV-MA-AS322-08 Zinc

Type IV method

 

1. Principle

After removal of alcohol, zinc is determined directly in the wine by atomic absorption spectrophotometry.

2. Apparatus

 

2.1.  Rotary evaporator and thermostatically controlled water bath.

2.2.  Atomic absorption spectrophotometer equipped with an air‑acetylene burner.

2.3.  Zinc hollow cathode lamp.

3. Reagents

The water used must be double distilled in borosilicate glass apparatus or of an equivalent degree of purity.

3.1.  Standard solution containing zinc, 1 g/L

Use of a commercial standard zinc solution is preferred. Alternatively this so­lution may be prepared by dissolving 4.3975 g of zinc sulfate, Zn, in water and making up the volume to one liter.

3.2.  Dilute standard solution containing 100 mg of zinc per liter.

4. Procedure

 

4.1.  Preparation of sample

Remove the alcohol from 100 mL of wine by reducing the volume of the sample to half its original value using a rotary evaporator (50 to 60 C). Make up to the original volume of 100 ml, with double distilled water.

4.2.  Calibration

Place 0.5, 1, 1.5 and 2 ml, of the solution containing 100 mg zinc per liter into each one of four 100 mL volumetric flasks and make up to the mark with double distilled water. The solutions prepared in this way contain 0.5, 1, 1.5 and 2 mg of zinc per liter respectively.

4.3.  Determination

Set the absorbance wavelength to 213.9 nm.  Zero the absorbance scale using double distilled water. Aspirate the wine directly into the burner of the spectrophotometer, followed in succession by the four standard solutions. Record the absor­bance and repeat each measurement.

5. Expression of results

5.1.  Method of calculation

Plot a graph giving the variation in absorbance as a function of zinc concentration in the standard solutions. Record the mean value of the absorbance obtained with the diluted wine sample on this graph and determine its zinc concentration to one decimal place.

OIV-MA-AS322-09 Silver

Type IV method

 

1. Principle

 

The method is based on the use of atomic absorption spectrophotometry after ashing the sample.

2. Apparatus

 

2.1.  Platinum dish.

2.2.  Water bath, thermostatically controlled to 100 C

2.3.  Furnace set at 500 to 525 C.

2.4.  Atomic absorption spectrophotometer.

2.5.  Silver hollow cathode lamp.

2.6.  Gas supplies: air, acetylene.

3. Reagents

 

3.1.  Silver nitrate, AgN0₃.

3.2.  Nitric acid, (ρ₂₀ = 1.38 g/mL), 65%.

3.3.  Nitric acid, diluted 1/10 (v/v) with distilled water.

3.4.  Solution containing 1 g of silver per L.

Use of a standard commercial silver solution is preferred. Alternatively this solution may be prepared by dissolving 1.575 g of silver nitrate in dilute nitric acid and making up to a volume of 1,000 mL with dilute nitric acid (3.3).Solution containing 10 mg of silver per L.

3.5.  Take 10 mL of the 1 mg/L solution and make up to 1 L with dilute nitric acid.

4. Procedure

 

4.1.  Preparation of sample

Place 20 mL of the sample in a platinum dish and evaporate to dryness over a boiling water bath. Ash in the furnace at a temperature of 500 to 525 C. Moisten the white ash with 1 mL of concentrated nitric acid (3.2). Evaporate over a boiling water bath, repeat the addition of 1 mL nitric acid (3.2) and evaporate a second time. Add 5 mL of dilute nitric acid (3.3) and heat gently until dissolved.

4.2.  Calibration

Pipette 2, 4, 6, 8, 10 and 20 mL of solution (3.5) respectively into each of size 100 mL volumetric flasks and make up to the mark with dilute nitric acid (3.3): the solutions contain 0.20, 0.40, 0.60, 0.80, 1.0 and 2.0 mg of silver per liter respectively.

4.3 Set the absorbance wavelength to 328.1 nm. Adjust zero using double distilled water. Measure the absorbance directly of successive standard solutions (4.2) and carry out in duplicate.

5. Expression of results

Plot a graph showing the variation in absorbance as a function of the silver concentration in the standard solutions.

Using the measured absorbance of the sample read the concentration C in mg/L from the calibration curve.

The concentration of silver in the wine is given in milligrams per liter by

It is quoted to two decimal places.

Note: Select the concentration of the solutions for the preparation of the calibration curve. The volume of sample taken and the final volume of the liquid should be appropriate for the sensitivity of the apparatus to be used.

OIV-MA-AS322-12 Analysis of mineral elements in wines using ICP-AES inductively coupled plasma/atomic emission spectrometry)

Type III method

 

1. Warning

Safety precautions - When handling acids, operators should protect their hands and eyes. Acids must be handled under a suitable hood.

2. Scope

This method specifies an inductively coupled plasma atomic emission spectroscopy (ICP-AES) method to determine the concentration of the following elements in wines:

-Major mineral elements:

• Potassium (up to 1500 mg/L)
• Calcium (up to 250 mg/L)
• Magnesium (up to 150 mg/L)
• Sodium (up to 100 mg/L)

Minor mineral elements:

• Iron (1 to 10 mg/L)
• Copper (0.1 to 5 mg/L)
• Zinc (0.5 to 5 mg/L)
• Manganese (0.5 to 5 mg/L)
• Strontium (0.1 to 3 mg/L)
• Aluminium  (0.75 to 7.5 mg/L)
• Barium (0.1 to 5 mg/L)

3. Principle

3.1.  Simultaneous analysis of major and minor elements

A 1:5 dilution is used to prepare the samples in this method in order to be able to analyse both the major and minor elements.

The calibration range contains ethanol (2.5%) to take into account the matrix effects related to its presence during nebulisation and at the plasma temperature, along with nitric acid (HNO₃ - 1%) which is used to stabilise the solutions.

The lines (scandium at 5 mg/L) and (caesium as 1% in Cs₎ proposed in this method can be used as an internal standard in order to minimise the impact of other non-spectral interferences.

Other internal standards, chosen wisely, may also be used in order to optimise the method, such as .

Caesium, in the form of Cs_. also serves as an ionic buffer when used as an internal standard. The presence of this buffer therefore sets the ionisation balances of the other components. Caesium chloride, CsCl, can also be used as an ionic buffer.

The internal standards and ionic buffer are prepared in the same flask and then introduced into the sample through the addition of a third channel in the peristaltic pump before entering the nebuliser as a homogenous mixture.

3.2.  Analysis of the major elements only

The analysis of the major elements only can also be performed by carrying out a 1:50 dilution of the sample. Nitric acid (H - 1%) is added into the standards and the samples in order to stabilise the solutions.

Given the dilution performed, the matrix effects are considered negligible. The use of internal standards will not be necessary. Likewise, there will be no need to add ethanol to the calibration range.

4. Reagents and solutions

Unless otherwise specified, all the reagents used must be of a recognised analytical quality.

4.1.  Ultra-pure, demineralised water with a resistivity (greater than 18 MΩ), in accordance with the ISO 3696 standard.

4.2.  Certified mono-element solution(s) (to 1000 or 10,000 mg/L) for the mineral elements analysed and the internal standard (scandium for example).

4.3.  Internal control: certified reference material (wine) or sample from an intercomparison programme between laboratories, comprising the elements analysed.

4.4.  Nitric acid of a concentration greater than 60% (for trace analysis) (CAS No. 7697-37-2).

4.5.  Ethanol of a concentration greater than 95% (for trace analysis) (CAS No. 64-17-5).

4.6.  A solution of 1% nitric acid

Prepare a 1% nitric acid solution by adding 10 mL of nitric acid (4.4) into a 1000 mL flask.

5. Apparatus and equipment

5.1.  Optical emission spectrometer with excitation by induced argon plasma and dispersive system (for wavelength analysis, see table in section 7) with axial, radial or dual configuration and preferably sequential PM, CCD, CID or SCCD type detector.

Note 1: Multi-element analysis using a simultaneous type spectrometer is strongly advised if an internal standard is used in the method.

Note 2: Other systems for introducing the sample may be used in order to increase the sensitivity and robustness of the method (continuous flow injection system, microwave desolvation system (MWDS, etc.).

5.2.  Calibrated micropipettes making it possible to take volumes from 200 µL to 5 mL and/or class A 1.5 and 10 mL graduated pipettes.

5.3.  Class A volumetric flasks

Note 3: The equipment in contact with the sample must remain in the nitric acid solution (4.4) at a concentration of 10% for 12 hours and then be rinsed several times with the demineralised water (4.1).

In order to assess the robustness of the method on the instrument used, it is recommended that the Mg 279.800/Mg 285.213 intensity ratio is calculated; Mg 285.213 being an atomic line and Mg 279.800 being an ionic line.

6. Sample preparation

6.1.  Preparing the calibration range

The number of calibration solutions depends on the reliability required. At least five calibration solutions are needed. The reliability and accuracy of the results can be verified by analysing a reference material.

The range will be chosen according to the dilution performed. It should cover the scope of the various elements. It is important that the nitric acid concentration is the same in the standards and samples.

6.1.1.      Preparing a standard solution for simultaneous analysis of major and minor elements (1:5 dilution):

Using a micropipette (5.2), introduce the desired volume of standard, 2.5 mL of ethanol (4.5) and 1 mL of nitric acid (4.4) into a 100 mL flask (5.3). Make up to 100 mL with demineralised water (4.1) and mix.

6.1.2.      Preparing a standard solution for analysing major elements only (1:50 dilution):

Using a micropipette (5.2), introduce the desired volume of standard into a 100 mL flask (5.3), make up to 100 mL with nitric acid solution (4.6) and mix.

6.2.  Preparing the test samples

6.2.1.      Preparing test samples for simultaneous analysis of major and minor elements (1:5 dilution):

Using a graduated pipette or micropipette (5.2), introduce 10 mL of sample and 1 mL of nitric acid (4.4) into a 50 mL flask (5.3). Make up to 50 mL with demineralised water (4.1) and mix.

Sparkling wine samples must be subjected to degassing using an ultrasound bath for example, for at least 10 minutes.

Particularly for samples rich in sugar, mineralisation by microwave digestion in nitric acid is used to destroy organic compounds. Finally, a higher dilution may need to be considered due to a concentration which is too high for certain elements. In this case, the ethanol content may be adjusted accordingly in the solutions and standards.

 

Note 4: Depending on the robustness of the instrument used and given the use of the ionic buffer and internal standards, it is possible to work with a 1:2 dilution factor in order to improve the sensitivity of the method for trace elements. As a result, the calibration ranges, ethanol content and possibly the experimental parameters (power) must be modified.

 

6.2.2.      Preparing test samples for analysing major elements only (1:50 dilution)

Using a graduated pipette or micropipette (5.2), introduce 1 mL of wine sample and 0.5 mL of nitric acid (4.4) into a 50 mL flask (5.3). Make up to 100 mL with demineralised water (4.1) and mix.

7. Procedure

7.1.  Experimental parameters

The optimal instrument parameters that have enabled us to achieve the specificity for this method in terms of repeatability and reproducibility are described below. They are presented here as an example and may be modified depending on the instrument used.

Power: 1.3 kW

Plasma gas flow: 15 L/min

Auxiliary gas flow: 1.5 L/min

Nebuliser pressure: 200 kPa

Stabilisation period: 20 s

Measurement time per replicate: 5 s

Pump speed: 15 rpm

Rinsing time: 30 s

Internal standard inlet internal diameter: 0.51 mm

Sample inlet internal diameter: 0.8 mm

Turn the unit on (pump operational and plasma switched on) and clean the system for at least 20 minutes with 1% nitric acid (4.6).

Analyse a blank following the series of standards in increasing order of concentration. A reference sample (4.3) can be used as internal quality control to verify that the calibration is satisfactory. Next, analyse the blank again to ensure the absence of memory effect. Next, conduct the analysis of the samples by inserting a quality control every 10 samples and at the end of the analysis series.

A control chart can be drawn up from the results obtained in relation to the control sample in order to define the acceptance criteria and actions to be performed in the event of drift.

The analyses will be performed for each element with a minimum of 3 replicates.

Lines that can be used for the various elements (other lines may be used depending on the equipment).

 

Elements	Main line ()	Associated internal standard	Secondary line ()	Associated internal standard
K	769.897 (I) (1.6 eV)	Cs 697.327	766.491 (I) (1.6 eV)	Cs 697.327
Ca	317.933 (II) (10 eV)	Sc 335.372	315.887 (II) (10.1 eV)	Sc 335.372
Mg	285.213 (I) (4.3 eV)	Cs 697.327	279.800 (II) (10.6 eV)	Sc 335.372
Na	589.592 (I) (2.1 eV)	Cs 697.327
Fe	259.940 (II) (12.7 eV)	Sc 335.372	239.563 (II) (11.4 eV)	Sc 335.372
Cu	327.395 (I) (3.8 eV)	Cs 697.327	324.754 (I) (3.8 eV)	Cs 697.327
Zn	213.857 (I) (5.8 eV)	Cs 697.327	206.200 (II) (12.2 eV)	Sc 335.372
Mn	257.61 (II) (12.3 eV)	Sc 335.372	260.568 (II) (11 eV)	Sc 335.372
Sr	421.552 (II) (8.6 eV)	Sc 335.372	407.771 (II) (8.7 eV)	Sc 335.372
Al	396.152 (I) (3.1 eV)	Cs 697.327	167.019 (I) (7.4 eV)	Cs 697.327
Rb	780.026 (I) (1.6 eV)	Cs 697.327
Li	670.783 (I) (1.9 eV)	Cs 697.327
Ba	455.403 (II) (7.9 eV)	Sc 335.372
Sc	335.372 (II) (10.3 eV)
Cs	697.327 (I) (1.8 eV)

8. Calculation

Calculate the concentration of the elements in the sample using the following equation:

Where:

C: concentration of the element in the wine sample (mg/L)

Cm: concentration of the element in the diluted solution (mg/L)

Vt: volume of the dilution flask (mL) (here V=50 mL)

Vm: volume of the sample taken for dilution (mL) (here V=1 or 10 mL)

9. Precision

Elements	Repeatability (RSD %)	Reproducibility (RSD %)	LD (mg/L)	LQ (mg/L)	Recovery rate
K	2.3	5.5	major	major	Between 80% and 120%
Ca	3.5	11.3	major	major
Mg	2.4	8.9	major	major
Na	2.6	9.1	major	major
Fe	2.2	6.9	0.08	0.25
Cu	13.4	15.8	0.03	0.10
Zn	3.6	6.5	0.03	0.10
Mn	4.7	7.0	0.03	0.10
Al	5.6	17.0	0.03	0.10
Sr	2.1	9.9	0.03	0.10
Ba	8.2	20.8	0.03	0.10

APPENDIX:

Validation study – Results of the collaborative trials

A validation study was performed in November 2011 (pre-study) and in February 2012 (validation study) in accordance with ISO 5725 and resolution OENO 6/2000.

Pre-study:

3 samples (dry white wine, red wine and sweet white wine), spiked with Al, Fe,

Cu, Sr, Ba, Mn and Zn.

	Samples
Element (mg/L)	Red wine	Dry white wine	Sweet wine
K	1258	725	841
Ca	50	75	81
Na	20	28	24
Mg	78	70	66
Al	1.29	1.33	1.97
Fe	8.12	6.91	9.29
Cu	0.86	0.86	0.94
Sr	1.07	1.08	1.07
Ba	0.77	0.72	0.63
Mn	1.6	2.01	1.77
Zn	1.51	2.53	1.69

 

OIV-MA-AS322-13 Analysis of mineral elements in wines using ICP-AES (inductively coupled plasma/atomic emission spectrometry)

Type III method

1. Warning

 

Safety precautions - When handling acids, operators should protect their hands and eyes. Acids must be handled under a suitable hood.

2. Scope

 

This method specifies an inductively coupled plasma atomic emission spectroscopy (ICP-AES) method to determine the concentration of the following elements in wines:

Major mineral elements:

• Potassium (up to 1500 mg/L)
• Calcium (up to 250 mg/L)
• Magnesium (up to 150 mg/L)
• Sodium (up to 100 mg/L)

Minor mineral elements:

• Iron (1 to 10 mg/L)
• Copper (0.1 to 5 mg/L)
• Zinc (0.5 to 5 mg/L)
• Manganese (0.5 to 5 mg/L)
• Strontium  (0.1 to 3 mg/L)
• Aluminium  (0.75 to 7.5 mg/L)
• Barium (0.1 to 5 mg/L)

3. Principle

3.1.  Simultaneous analysis of major and minor elements

A 1:5 dilution is used to prepare the samples in this method in order to be able to analyse both the major and minor elements.

The calibration range contains ethanol (2.5%) to take into account the matrix effects related to its presence during nebulisation and at the plasma temperature, along with nitric acid (HN - 1%) which is used to stabilise the solutions.

The lines (scandium at 5 mg/L) and (caesium as 1% in CsN₎ proposed in this method can be used as an internal standard in order to minimise the impact of other non-spectral interferences.

Other internal standards, chosen wisely, may also be used in order to optimise the method, such as .

Caesium, in the form of CsN_. also serves as an ionic buffer when used as an internal standard. The presence of this buffer therefore sets the ionisation balances of the other components. Caesium chloride, CsCl, can also be used as an ionic buffer.

The internal standards and ionic buffer are prepared in the same flask and then introduced into the sample through the addition of a third channel in the peristaltic pump before entering the nebuliser as a homogenous mixture.

3.2.  Analysis of the major elements only

The analysis of the major elements only can also be performed by carrying out a 1:50 dilution of the sample. Nitric acid (HNO₃ - 1%) is added into the standards and the samples in order to stabilise the solutions.

Given the dilution performed, the matrix effects are considered negligible. The use of internal standards will not be necessary. Likewise, there will be no need to add ethanol to the calibration range.

 

4. Reagents and solutions

Unless otherwise specified, all the reagents used must be of a recognised analytical quality.

4.1.  Ultra-pure, demineralised water with a resistivity (greater than 18 MΩ), in accordance with the ISO 3696 standard.

4.2.  Certified mono-element solution(s) (to 1000 or 10,000 mg/L) for the mineral elements analysed and the internal standard (scandium for example).

4.3.  Internal control: certified reference material (wine) or sample from an intercomparison programme between laboratories, comprising the elements analysed.

4.4.  Nitric acid of a concentration greater than 60% (for trace analysis) (CAS No. 7697-37-2).

4.5.  Ethanol of a concentration greater than 95% (for trace analysis) (CAS No. 64-17-5).

4.6.  A solution of 1% nitric acid

Prepare a 1% nitric acid solution by adding 10 mL of nitric acid (4.4) into a 1000 mL flask.

5. Apparatus and equipment

 

5.1.  Optical emission spectrometer with excitation by induced argon plasma and dispersive system (for wavelength analysis, see table in section 7) with axial, radial or dual configuration and preferably sequential PM, CCD, CID or SCCD type detector.

Note 1: Multi-element analysis using a simultaneous type spectrometer is strongly advised if an internal standard is used in the method.

Note 2: Other systems for introducing the sample may be used in order to increase the sensitivity and robustness of the method (continuous flow injection system, microwave desolvation system (MWDS, etc.).

5.2.  Calibrated micropipettes making it possible to take volumes from 200 µL to 5 mL and/or class A 1.5 and 10 mL graduated pipettes.

5.3.  Class A volumetric flasks

Note 3: The equipment in contact with the sample must remain in the nitric acid solution (4.4) at a concentration of 10% for 12 hours and then be rinsed several times with the demineralised water (4.1).

In order to assess the robustness of the method on the instrument used, it is recommended that the Mg 279.800/Mg 285.213 intensity ratio is calculated; Mg 285.213 being an atomic line and Mg 279.800 being an ionic line.

6. Sample preparation

6.1.  Preparing the calibration range

The number of calibration solutions depends on the reliability required. At least five calibration solutions are needed. The reliability and accuracy of the results can be verified by analysing a reference material.

The range will be chosen according to the dilution performed. It should cover the scope of the various elements. It is important that the nitric acid concentration is the same in the standards and samples.

6.1.1.      Preparing a standard solution for simultaneous analysis of major and minor elements (1:5 dilution):

Using a micropipette (5.2), introduce the desired volume of standard, 2.5 mL of ethanol (4.5) and 1 mL of nitric acid (4.4) into a 100 mL flask (5.3). Make up to 100 mL with demineralised water (4.1) and mix.

6.1.2.      Preparing a standard solution for analysing major elements only (1:50 dilution):

Using a micropipette (5.2), introduce the desired volume of standard into a 100 mL flask (5.3), make up to 100 mL with nitric acid solution (4.6) and mix.

6.2.  Preparing the test samples

6.2.1.      Preparing test samples for simultaneous analysis of major and minor elements (1:5 dilution):

Using a graduated pipette or micropipette (5.2), introduce 10 mL of sample and 1 mL of nitric acid (4.4) into a 50 mL flask (5.3). Make up to 50 mL with demineralised water (4.1) and mix.

Sparkling wine samples must be subjected to degassing using an ultrasound bath for example, for at least 10 minutes.

Particularly for samples rich in sugar, mineralisation by microwave digestion in nitric acid is used to destroy organic compounds. Finally, a higher dilution may need to be considered due to a concentration which is too high for certain elements. In this case, the ethanol content may be adjusted accordingly in the solutions and standards.

Note 4: Depending on the robustness of the instrument used and given the use of the ionic buffer and internal standards, it is possible to work with a 1:2 dilution factor in order to improve the sensitivity of the method for trace elements. As a result, the calibration ranges, ethanol content and possibly the experimental parameters (power) must be modified.

6.2.2.      Preparing test samples for analysing major elements only (1:50 dilution)

Using a graduated pipette or micropipette (5.2), introduce 1 mL of wine sample and 0.5 mL of nitric acid (4.4) into a 50 mL flask (5.3). Make up to 100 mL with demineralised water (4.1) and mix.

7. Procedure

Experimental parameters

 

The optimal instrument parameters that have enabled us to achieve the specificity for this method in terms of repeatability and reproducibility are described below. They are presented here as an example and may be modified depending on the instrument used.

Power: 1.3 kW

Plasma gas flow: 15 L/min

Auxiliary gas flow: 1.5 L/min

Nebuliser pressure: 200 kPa

Stabilisation period: 20 s

Measurement time per replicate: 5 s

Pump speed: 15 rpm

Rinsing time: 30 s

Internal standard inlet internal diameter: 0.51 mm

Sample inlet internal diameter: 0.8 mm

Turn the unit on (pump operational and plasma switched on) and clean the system for at least 20 minutes with 1% nitric acid (4.6).

Analyse a blank following the series of standards in increasing order of concentration. A reference sample (4.3) can be used as internal quality control to verify that the calibration is satisfactory. Next, analyse the blank again to ensure the absence of memory effect. Next, conduct the analysis of the samples by inserting a quality control every 10 samples and at the end of the analysis series.

A control chart can be drawn up from the results obtained in relation to the control sample in order to define the acceptance criteria and actions to be performed in the event of drift.

The analyses will be performed for each element with a minimum of 3 replicates.

Lines that can be used for the various elements (other lines may be used depending on the equipment).

 

Elements	Main line ()	Associated internal standard	Secondary line ()	Associated internal standard
K	769.897 (I) (1.6 eV)	Cs 697.327	766.491 (I) (1.6 eV)	Cs 697.327
Ca	317.933 (II) (10 eV)	Sc 335.372	315.887 (II) (10.1 eV)	Sc 335.372
Mg	285.213 (I) (4.3 eV)	Cs 697.327	279.800 (II) (10.6 eV)	Sc 335.372
Na	589.592 (I) (2.1 eV)	Cs 697.327
Fe	259.940 (II) (12.7 eV)	Sc 335.372	239.563 (II) (11.4 eV)	Sc 335.372
Cu	327.395 (I) (3.8 eV)	Cs 697.327	324.754 (I) (3.8 eV)	Cs 697.327
Zn	213.857 (I) (5.8 eV)	Cs 697.327	206.200 (II) (12.2 eV)	Sc 335.372
Mn	257.61 (II) (12.3 eV)	Sc 335.372	260.568 (II) (11 eV)	Sc 335.372
Sr	421.552 (II) (8.6 eV)	Sc 335.372	407.771 (II) (8.7 eV)	Sc 335.372
Al	396.152 (I) (3.1 eV)	Cs 697.327	167.019 (I) (7.4 eV)	Cs 697.327
Rb	780.026 (I) (1.6 eV)	Cs 697.327
Li	670.783 (I) (1.9 eV)	Cs 697.327
Ba	455.403 (II) (7.9 eV)	Sc 335.372
Sc	335.372 (II) (10.3 eV)
Cs	697.327 (I) (1.8 eV)

 

8. Calculation

Calculate the concentration of the elements in the sample using the following equation:

Where:

C: concentration of the element in the wine sample (mg/L)

Cm: concentration of the element in the diluted solution (mg/L)

Vt: volume of the dilution flask (mL) (here V=50 mL)

Vm: volume of the sample taken for dilution (mL) (here V=1 or 10 mL)

9. Precision

 

Elements	Repeatability (RSD %)	Reproducibility (RSD %)	LD (mg/L)	LQ (mg/L)	Recovery rate
K	2.3	5.5	major	major	Between 80% and 120%
Ca	3.5	11.3	major	major
Mg	2.4	8.9	major	major
Na	2.6	9.1	major	major
Fe	2.2	6.9	0.08	0.25
Cu	13.4	15.8	0.03	0.10
Zn	3.6	6.5	0.03	0.10
Mn	4.7	7.0	0.03	0.10
Al	5.6	17.0	0.03	0.10
Sr	2.1	9.9	0.03	0.10
Ba	8.2	20.8	0.03	0.10

 

Appendix :Validation study – Results of the collaborative trials

A validation study was performed in November 2011 (pre-study) and in February 2012 (validation study) in accordance with ISO 5725 and resolution OENO 6/2000.

Pre-study:

3 samples (dry white wine, red wine and sweet white wine), spiked with Al, Fe,

Cu, Sr, Ba, Mn and Zn.

 

	Samples
Element (mg/L)	Red wine	Dry white wine	Sweet wine
K	1258	725	841
Ca	50	75	81
Na	20	28	24
Mg	78	70	66
Al	1.29	1.33	1.97
Fe	8.12	6.91	9.29
Cu	0.86	0.86	0.94
Sr	1.07	1.08	1.07
Ba	0.77	0.72	0.63
Mn	1.6	2.01	1.77
Zn	1.51	2.53	1.69

SAMPLES

	White wine 1			White wine 2
Element	Ref value (mg/L)	Spike (mg/L)	Recovery %	Ref value (mg/L)	Spike (mg/L)	Recovery %
K	754	0	98	1080	351	96
Ca	83	11	98	76	0	102
Na	50	28	105	24	0	100
Mg	65	0	98	72	7	102

Al	0.50	0	100	1.19	1	104
Fe	2.86	1	94	1.71	0	97
Cu	0.04	0	no add.	0.71	1	103
Sr	1.27	1	105	0.22	0	108
Ba	0.08	0	102	0.64	1	96
Mn	1.84	1	98	1.12	0	102
Zn	1.40	0	100	2.12	1	102

 

 

	Red wine 1			Red wine 2
Element	Ref value (mg/L)	Spike (mg/L)	Recovery %	Ref value (mg/L)	Spike (mg/L)	Recovery %
K	1160	70	100	1371	316	95
Ca	62	1	103	67	7	101
Na	71	56	100	19	0	100
Mg	82	7	102	80	0	99
Al	0.81	0	105	1.82	1	103
Fe	4.90	0	101	4.55	0	101
Cu	0.46	0	102	0.12	0	65
Sr	0.28	0	102	1.32	1	105
Ba	0.12	0	102	0.62	1	97
Mn	1.81	1	100	1.10	0	101
Zn	0.95	0	107	1.68	1	101

 

	Sweet wine 1			Sweet wine 2
Element	Ref value (mg/L)	Spike (mg/L)	Recovery %	Ref value (mg/L)	Spike (mg/L)	Recovery %
K	1105	246	96	832	0	102
Ca	85	4	99	92	10	101
Na	68	42	98	21	0	100
Mg	63	0	97	66	6	101
Al	1.65	1	101	0.80	0	96
Fe	3.03	0	97	4.63	0	101
Cu	0.73	1	101	0.12	0	94
Sr	1.73	1	106	0.22	0	96
Ba	0.11	0	94	0.34	0	90
Mn	1.01	0	99	1.62	1	102
Zn	1.53	1	102	1.18	0	100

 

Participant laboratories had the choice to carry out the analysis of elements

• either in two steps: high dilution for major elements and low dilution for minor elements, preferably with internal standards.
• or in one step: the same dilution for all elements with internal standards.

For each sample number and for each determination, the first individual value was used. The two individual portions of blind identical replicas per laboratory are considered as a single material.

Outlier elimination was performed using a sequential application of the Cochran (applied to variances) and Grubbs (applied to mean values) tests (at a 2.5% probability (P) level, 1-tail for Cochran and 2-tail for Grubbs) until no further outliers were flagged or until a drop of 22.2% in the original number of laboratories providing valid data occurred.

With the exception of the element calcium in the "sweet wine 2" sample, which exhibits a Horrat R value of 2.2, all the elements were compliant. For this sample, 93% of the laboratories have a satisfactory Z-score (14 results) and 7% of the laboratories have a questionable Z-score (1 result). Consequently, as the five other samples were compliant for the determination of calcium, including another sweet wine sample with the same calcium concentration, it was decided to validate this element and to include it in the analytical method.

For the determination of major elements, 9 laboratories used a high dilution and 6 laboratories used a single dilution for all (major and minor) elements. There were no differences between the results of both groups.

Tableau 1 - Potassium

Statistical parametres	White Wine 1	White Wine   2	Red wine 1	Red wine 2	Sweet wine 1	Sweet wine 1
Total	15,00	15,00	15,00	15,00	15,00	15,00
Accepted	13,00	13,00	14,00	11,00	14,00	14,00
Repetitions	2,00	2,00	2,00	2,00	2,00	2,00
Vréf (mg/L)	754,38	1079,82	1160,33	1370,96	1105,46	831,62
Limit of repeatability - r	22,45	47,32	132,68	50,64	124,78	42,92
RSD r (%)	1,10	1,50	4,00	1,30	4,00	1,80
RSD r Horwitz	3,90	3,69	3,65	3,56	3,68	3,84
r Horrat	0,30	0,40	1,10	0,40	1,10	0,50
Limite de reproductibility - R	139,25	182,82	165,46	147,56	176,10	142,93
RSD R (%)	6,50	6,00	5,00	3,80	5,60	6,10
RSD R Horwitz	5,90	5,59	5,53	5,39	5,57	5,82
R Horrat	1,10	1,10	0,90	0,70	1,00	1,00

Tableau 2 - Calcium

Statistical parametres	White Wine 1	White Wine 2	Red wine 1	Red wine 2	Sweet wine 1	Sweet wine 1
Total	15,00	15,00	15,00	15,00	15,00	15,00
Accepted	10,00	10,00	13,00	10,00	13,00	15,00
Repetitions	2,00	2,00	2,00	2,00	2,00	2,00
Vréf (mg/L)	85,37	73,43	67,68	66,00	78,35	92,39
Limit of repeatability - r	3,30	4,12	4,60	2,86	7,96	26,66
RSD r (%)	2,10	2,00	2,40	1,50	3,60	10,20
RSD r Horwitz	5,85	5,53	5,60	5,62	5,48	5,34
r Horrat	0,30	0,40	0,40	0,30	0,70	1,90
Limite de reproductibility - R	10,68	10,45	42,58	9,51	29,85	45,60
RSD R (%)	4,40	5,00	22,20	5,10	13,50	17,40
RSD R Horwitz	8,19	8,38	8,48	8,52	8,30	8,10
R Horrat	0,50	0,60	2,60	0,60	0,60	2,20

Tableau 3 - Sodium

Statistical parametres	White Wine 1	White Wine   2		Red wine 1	Red wine 2	Sweet wine 1	Sweet wine 1
Total	15,00	15,00		15,00	15,00	15,00	15,00
Accepted	15,00	13,00		12,00	12,00	14,00	15,00
Repetitions	2,00	2,00		2,00	2,00	2,00	2,00
Vréf (mg/L)	50,50		24,09	71,43	18,76	67,91	21,42
Limit of repeatability - r	3,00		1,32	2,53	1,73	5,20	1,85
RSD r (%)	2,10		1,90	1,20	3,30	2,70	3,00
RSD r Horwitz	5,85		6,54	5,55	6,79	5,60	6,6
r Horrat	0,30		0,30	0,20	0,50	0,50	0,50
Limite de reproductibility - R	9,41		6,09	15,19	6,72	13,09	6,49
RSD R (%)	6,60		9,90	7,50	12,70	6,80	10,70
RSD R Horwitz	8,87		9,91	8,42	10,29	8,48	10,09
R Horrat	0,70		0,90	0,90	1,20	0,80	1,10

Tableau 4 - Magnésium

Statistical parametres	White Wine 1	White Wine   2	Red wine 1	Red wine 2	Sweet wine 1	Sweet wine 1
Total	15,00	15,00	15,00	15,00	15,00	15,00
Accepted	15,00	15,00	14,00	14,00	13,00	14,00
Repetitions	2,00	2,00	2,00	2,00	2,00	2,00
Vréf (mg/L)	65,30	72,0	82,15	80,01	62,63	65,53
Limit of repeatability - r	3,43	4,29	10,27	7,25	5,32	2,27
RSD r (%)	1,90	2,10	4,40	3,20	3,00	1,20
RSD r Horwitz	5,63	5,55	5,44	5,46	5,67	5,63
r Horrat	0,30	0,40	0,80	0,60	0,50	0,20
Limite de reproductibility - R	15,26	16,33	29,80	20,23	15,86	13,74
RSD R (%)	8,30	8,00	12,80	8,90	8,90	7,40
RSD R Horwitz	8,53	8,40	8,24	8,2	8,58	8,53
R Horrat	1,00	1,00	1,60	1,10	1,00	0,90

Tableau 5 - Aluminium

Statistical parametres	White Wine 1	White Wine   2	Red wine 1	Red wine 2	Sweet wine 1	Sweet wine 1
Total	15,00	15,00	15,00	15,00	15,00	15,00
Accepted	10,00	9,00	8,00	8,00	9,00	8,00
Repetitions	2,00	2,00	2,00	2,00	2,00	2,00
Vréf (mg/L)	0,50	1,19	0,81	1,82	1,65	0,80
Limit of repeatability - r	0,19	0,11	0,22	0,15	0,15	0,05
RSD r (%)	13,10	3,30	9,40	2,80	3,20	2,10
RSD r Horwitz	11,71	10,29	10,89	9,65	9,79	10,93
r Horrat	1,10	0,30	0,90	0,30	0,30	0,20
Limite de reproductibility - R	0,42	0,33	0,33	0,46	0,97	0,41
RSD R (%)	29,80	10,00	14,20	8,90	20,80	18,10
RSD R Horwitz	17,75	15,59	16,50	14,61	14,84	16,56
R Horrat	1,70	0,60	0,90	0,60	1,40	1,10

Tableau 6 - Fer

Statistical parametres	White Wine 1	White Wine   2	Red wine 1	Red wine 2	Sweet wine 1	Sweet wine 1
Total	10,00	10,00	10,00	10,00	10,00	10,00
Accepted	6,00	7,00	7,00	6,00	7,00	7,00
Repetitions	2,00	2,00	2,00	2,00	2,00	2,00
Vréf (mg/L)	2,86	1,71	4,90	4,55	3,03	4,63
Limit of repeatability - r	0,19	0,06	0,57	0,33	0,21	0,70
Limit of repeatability - r	0,19	0,06	0,57	0,33	0,21	0,70
RSD r (%)	2,30	1,30	4,10	2,60	2,40	0,50
RSD r Horwitz	9,02	9,74	8,31	8,41	8,94	8,38
r Horrat	0,30	0,10	0,50	0,30	0,30	0,10
Limite de reproductibility - R	0,20	0,29	0,99	0,34	0,34	2,52
RSD R (%)	2,50	6,10	7,10	2,60	3,90	19,20
RSD R Horwitz	13,66	14,76	12,59	12,74	13,54	12,70
R Horrat	0,20	0,40	0,60	0,20	0,30	1,50

Tableau 7 - Cuivre

Statistical parametres	White Wine 1		White Wine   2	Red wine 1	Red wine 2	Sweet wine 1	Sweet wine 1
Total	9,00		10,00	10,00	10,00	10,00	10,00
Accepted	7,00		10,00	8,00	10,00	8,00	10,00
Repetitions	2,00		2,00	2,00	2,00	2,00	2,00
Vréf (mg/L)	0,04		0,71	0,46	0,12	0,73	0,12
Limit of repeatability - r	0,03		0,10	0,08	0,05	0,03	0,10
RSD r (%)	24,30	4,80		6,00	14,40	1,70	29,00
RSD r Horwitz	16,95	11,12		11,87	14,62	11,07	14,55
r Horrat	1,40	0,40		0,50	1,00	0,20	2,00
Limite de reproductibility - R	0,03	0,21		0,09	0,05	0,14	0,10
RSD R (%)	24,30	10,40		6,80	16,40	6,80	30,10
RSD R Horwitz	25,68	16,84		17,98	22,15	16,77	22,05
R Horrat	0,90	0,60		0,40	0,70	0,40	1,40

Tableau 8 – Strontium

Statistical parametres	White Wine 1	White Wine   2	Red wine 1	Red wine 2	Sweet wine 1	Sweet wine 1
Total	8,00	8,00	8,00	8,00	8,00	8,00
Accepted	7,00	7,00	7,00	6,00	7,00	6,00
Repetitions	2,00	2,00	2,00	2,00	2,00	2,00
Vréf (mg/L)	1,27	0,22	0,28	1,32	1,73	0,22
Limit of repeatability - r	0,03	0,01	0,04	0,06	0,12	0,00
RSD r (%)	1,00	1,70	5,50	1,70	2,60	0,50
RSD r Horwitz	10,19	13,25	12,76	10,13	9,72	13,30
r Horrat	0,01	0,10	0,40	0,20	0,30	0,00
Limite de reproductibility - R	0,18	0,07	0,12	0,09	0,24	0,12
RSD R (%)	5,10	11,40	15,30	2,50	5,00	20,00
RSD R Horwitz	15,44	20,08	19,34	15,34	14,73	22,15
R Horrat	0,30	0,60	0,80	0,20	0,30	1,00

Tableau 9 - Barium

Statistical parametres	White Wine 1	White Wine   2	Red wine 1	Red wine 2	Sweet wine 1	Sweet wine 1
Total	8,00	8,00	8,00	8,00	8,00	8,00
Accepted	7,00	8,00	8,00	7,00	8,00	8,00
Repetitions	2,00	2,00	2,00	2,00	2,00	2,00
Vréf (mg/L)	0,08	0,64	0,12	0,62	0,11	0,34
Limit of repeatability - r	0,01	0,38	0,01	0,16	0,01	0,06
RSD r (%)	5,70	21,00	3,60	9,20	3,30	6,30
RSD r Horwitz	15,33	11,30	14,52	11,34	14,73	12,41
r Horrat	0,40	1,90	0,20	0,80	0,20		0,50
Limite de reproductibility - R	0,04	0,38	0,05	0,54	0,05		0,24
RSD R (%)	18,80	21,00	13,90	30,07	15,80		24,50
RSD R Horwitz	23,23	17,12	22,00	17,18	22,32		18,80
R Horrat	0,80	1,20	0,60	1,80	0,70		1,30

Tableau 10 - Manganèse

Statistical parametres	White Wine 1	White Wine   2	Red wine 1	Red wine 2	Sweet wine 1	Sweet wine 1
Total	10,00	10,00	10,00	10,00	10,00	10,00
Accepted	9,00	10,00	9,00	10,00	8,00	8,00
Repetitions	2,00	2,00	2,00	2,00	2,00	2,00
Vréf (mg/L)	1,84	1,12	1,81	1,10	0,11	1,62
Limit of repeatability - r	0,09	0,21	0,49	0,14	0,13	0,60
RSD r (%)	1,60	6,50	9,60	4,50	4,60	1,30
RSD r Horwitz	9,64	10,38	9,66	10,41	10,55	9,82
r Horrat	0,20	0,60	1,00	0,40	0,40	0,10
Limite de reproductibility - R	0,25	0,21	0,49	0,22	0,22	0,38
RSD R (%)	4,80	6,50	9,60	7,10	7,10	8,30
RSD R Horwitz	14,60	15,73	14,63	15,78	15,98	14,88
R Horrat	0,30	0,40	0,70	0,50	0,30	0,60

Tableau 11 - Zinc

Statistical parametres	White Wine 1		White Wine   2	Red wine 1	Red wine 2	Sweet wine 1	Sweet wine 1
Total	10,00		10,00	10,00	10,00	10,00	10,00
Accepted	7,00		8,00	9,00	8,00	7,00	7,00
Repetitions	2,00		2,00	2,00	2,00	2,00	2,00
Vréf (mg/L)	1,40		2,12	0,95	1,68	1,53	1,18
Limit of repeatability - r	0,09		0,16	0,22	0,10	0,18	0,05
RSD r (%)	2,40		2,60	8,40	2,20	4,20	1,60
RSD r Horwitz	10,03		9,43	10,65	9,77	9,91	10,30
r Horrat	0,20		0,30	0,80	0,20	0,40	0,20
Limite de reproductibility - R	0,10		0,39	0,29	0,36	0,22	0,22
RSD R (%)	2,40	6,50	10,70	7,60	5,10	6,70
RSD R Horwitz	15,20	14,28	16,13	14,80	15,01	15,61
R Horrat	0,20	0,50	0,70	0,50	0,30	0,40

2/ Laboratoires participants :

• State General Laboratory, NMR Lab, Nicosia Chypre
• ANALAB CHILE S.A., Santiago Chile
• CISTA, National Reference Laboratoty Brno Czech Republic
• Laboratório de Análises- REQUIMTE- FCT/UNL, Caparica Portugal
• Laboratório Central de Análises - Universidade de Aveiro Portugal
• Laboratory of National Center of Alcoholic Beverages Testing, Chisinau Republic of Moldova
• National Research Institute of Brewing, Higashihiroshima Japon
• Instituto Nacional de Vitivinicultura, Laboratorio General, Mendoza Argentine
• LFZ Wein und Obstbau, Klosterneuburg Autriche
• Laboratorio Arbitral Agroalimentario, Madrid Spain
• Laboratoire SCL de Bordeaux-Pessac France