Validation of sorbic acid assay method in wines using liquid chromatography (OENO 6/2006)
RESOLUTION OIV-OENO 687-2023
VALIDATION OF SORBIC ACID ASSAY METHOD IN WINES USING LIQUID CHROMATOGRAPHY (OENO 06/2006)
|
WARNING: this resolution modifies the following resolution: - OENO 6/2006 |
THE GENERAL ASSEMBLY,
IN VIEW of article 2, paragraph 2 iv of the Agreement of 3rd April 2001 establishing the International Organisation of Vine and Wine,
CONSIDERING the proposal of the “Methods of Analysis” Sub-commission,
CONSIDERING the resolution OENO 06/2006 “Determination of sorbic, benzoic and salicylic acid content in wine by the use of high-performance liquid chromatography”, adopted in 2006
CONSIDERING that this validation concerns only the sorbic acid,
DECIDES to add the annex A: Validation of Sorbic Acid Assay Method in Wines Using Liquid Chromatography, and to change the sorbic acid method from type IV to type II.
DECIDES to modify the resolution OENO 06/2006 “Determination of sorbic, benzoic and salicylic acid content in wine by the use of high-performance liquid chromatography” and consequently method OIV-MAAS313-20 with the following modifications, where the additions can be seen in bold letters and the deleted parts are strikethrough:
2. Scope
All wines and grape musts, especially those likely to contain only traces of sorbic, benzoic or salicylic acid. (demonstration from 1 mg/l).
3. Principle
The antiseptics are determined using HPLC by direct injection of the sample into a column functioning by isocratic reversed-phase partition chromatography with ultraviolet detection at a wavelength of 235 nm [1].
4.11. 50% vol. hydro-alcohol solution or other suitable concentration: put 500 ml of absolute alcohol (4.10) into a 1-litre flask and dilute to volume with distilled water (4.1)
5.7. Detector capable of functioning at an ultraviolet rating of 235 nm (1) and fitted with a circulating tank for HPLC (for example, 8 μl for 1 cm of optical thickness)
A 5- μm stationary phase HPLC column of the silica-type with immobilisation by octadecyl groups (C18), length 20 cm, inside diameter 4 mm (1)
6.2. Degas the elution solvent (4.6) for 5 minutes using the ultrasonic bath (5.2) or any other suitable way.
6.3. Filter the solvent using the device in (5.43)
8. Calculation
Having located the peaks of the acids to be determined in the sample, compare the peak area with those of the acids of a surrogate solution (4.13) with a known concentration C.
For example, let s be the peak area of the acid to be determined, and S is the peak area of the solution (4.13) with concentration C
 |
It is also possible to use a calibration curve and determine the concentration by interpolation.
9. Characteristics of the method
9.1. For Sorbic acid
Interlaboratory trial and correspondent results are described in annex A.
- r = 0.0148 x + 0.5498
- R = 0.0936 x + 1.5542
- x: sorbic acid concentration (mg/l)
9.2. For Benzoic and Salicylic acids
|
Sorbic acid |
Benzoic acid |
Salicylic acid |
|
|
Linearity range |
0 to 200 mg/l |
0 to 200 mg/l |
0 to 200 mg/l |
|
Accuracy (rate of recuperation) |
> 90 % |
> 90 % |
> 90 % |
|
Répétabilité : r* |
2% |
3% |
8% |
|
Reproducibility: R* |
8% |
9% |
12% |
|
Detection limit |
3 mg/l |
3 mg/l |
3 mg/l |
|
Quantification limit |
5 mg/l |
6 mg/l |
7 mg/l |
|
Uncertainty |
11% |
12% |
13% |
ANNEX A - Statistic data obtained from the results of the interlaboratory trials
The following parameters have been defined during an interlaboratory trial. This trial has been conducted by the laboratory “ Instituto dos Vinhos do Douro e do Porto (Portugal). “
Year of interlaboratory trial: 2020
1. Laboratories: 23 laboratories from 14 different countries
|
HBLA und Bundesamt für Wein- und Obstbau Klosterneuburg |
Austria |
|
Department of Agriculture |
Cyprus |
|
Czech Agriculture and Food Inspection Authority |
Czech Republic |
|
Comité Interprofessionnel du Vin de Champagne |
France |
|
Laboratoires Dubernet |
France |
|
Service Commun des Laboratoires-Laboratoire de Montpellier |
France |
|
Service Commun des Laboratoires-Laboratoire de Bordeaux |
France |
|
Landesuntersuchungsamt, Institut für Lebensmittelchemie |
Germany |
|
Lebensmittel- u. Veterinärinstitut Braunschweig/Hannover |
Germany |
|
National Food Chain Safety Office |
Hungary |
|
Unione Italiana Vini Servizi |
Italy |
|
Vassanelli Lab s.r.l. |
Italy |
|
AsureQuality Ltd Laboratory Services |
New Zealand |
|
Arcus Norway AS |
Norway |
|
ASAE-Autoridade de Segurança Alimentar e Económica |
Portugal |
|
Instituto dos Vinhos do Douro e do Porto |
Portugal |
|
RUDN University |
Russian Federation |
|
National Laboratory of Health, Environment and Food (Novo Gorica) |
Slovenia |
|
National Institute of Chemistry |
Slovenia |
|
National Laboratory of Health, Environment and Food (Novo Mesto) |
Slovenia |
|
Laboratorio Arbitral Agroalimentario. |
Spain |
|
Estación Enológica de Haro- La Rioja |
Spain |
|
Cukurova University Food Engineering Dept. |
Turkey |
2. Number of samples: 6 samples in duplicate
- 2 white wines: A/G, C/K
- 1 white wine - late harvest: I/O
- 1 red wine: D/M
- 1 rosé wine: B/F
- 1 red fortified wine (alcoholic strength - 19 % vol.): E/N
3. Analytical conditions
The analytical conditions are summarized in Table 1.
4. Individual results
The individual results for Sorbic Acid (mg/L) are summarized in Table 2.
5. Data Analysis
- Statistical analysis was performed according to the recommendations of the OIV to obtain precision data
- The values below the quantification limit were treated as normal values.
- Determination of outliers was assessed by Cochran and Grubbs test
- The results are summarized in tables 3 and 4.
- Repetibility and reproducibility limit according to sorbic acid concentration are represented in figure 1.
- The Z-score for each laboratory was evaluated against the global values for the different samples.The results are in figure 2.
TABLE 1 – ANALYTICAL CONDITIONS
|
Calibration Curve |
Column |
Detection |
Mobile phase |
Flow rate (mL/min) |
Column temperature (°C) |
Injection volume (µL) |
|
|
1 |
yes |
Altima C18LL 5 µm 250 x 4.6 mm |
λ = 235 nm |
Water pH=2.0 / MeOH/ THF (650/280/70) |
1 |
ambient |
20 |
|
2 |
yes |
C18 250 x 4.6 Luna Phenomenex |
λ = 235 nm |
0.389 Ammonium acetate in 1L water + 250 mL ACN (pH=4 adjusted w/ CH3COOH) |
1.25 |
35 |
20 |
|
3 |
yes |
Poreshell 120 EC-C18 .150 x 4.4 mm; 2.7 µm |
λ = 235 nm |
A: H2O 0.7 % THF (pH=2) /B: MeOH (80 % A e 20 % B) |
1.5 |
40 |
5 |
|
4 |
yes |
RP-18 (250-4) |
λ = 254 nm |
Ammonium acetate buffer (pH 4.4): MeOH = 70:30 |
1 |
40 |
20 |
|
6 |
yes |
PerfectSil Target ODS-3 HD. 5 µm. 250 x 4.6 mm |
λ = 235 nm |
ACN:Buffer solution (35:65); Buffer solution = Ammonium acetate (1.8 g/l) + Acetic acid. pH=4.3 |
1 |
40 |
2 |
|
7 |
yes |
PoroShell C18 4.6 x 75 mm; 2.7 µm |
λ = 235 nm |
Isocratic: 80 % H2O acid. with sulfuric acid; 20 % ACN |
1.5 |
25 |
20 |
|
8 |
yes |
Rezex-ROA- Organic acid H+ (8 %) -300 x 7.8 mm |
λ = 254 nm |
Elution solvent Sulfuric acid = 0.025M |
1 |
90 |
50 |
|
9 |
yes |
HICROM Ultrasphere 5 µm ODS column. 250 x 4.6 mm |
λ = 235 nm |
650 mL H2O pH 2 with 280 mL MeOH + 7 mL THF |
0.6 |
25 |
20 |
|
10 |
yes |
Teknokroma Trace Excel 120 ODSB 5 µm. 20 x 0.4 cm |
λ = 235 nm |
650 mL H2O pH 2 (HCl 0.1M) + 280 mL MeOH + 7 mL THF |
1 |
24 |
20 |
|
11 |
yes |
C18 5 µm. 200x4 mm |
λ = 235 nm |
||||
|
12 |
yes |
RP18 Chromolith 100 x 4.6 mm; 5 µm |
λ = 235 nm |
770 Water pH=2.3 (0.8 mL H3PO4): isopropanol 200 mL. ACN 30 mL |
1 |
25 |
10 |
|
13 |
yes |
Phenomenex Gemini 5 µm. C18; 150 x 2 mm |
λ = 240 nm |
0.925 g ammonium acetate + 1.2 L H2O + 0.8 L MeOH (pH 5.5 acetic acid) |
0.4 |
40 |
10 |
|
15 |
yes |
C18 5 µm. 200 x4 mm |
λ = 235 nm |
90 % v/v Water 15mL Acetic acid+ 15 g ammonium acetate 10 % v/v MeOH |
1 |
40 |
10 |
|
16 |
yes |
Prodigy 5 μm ODS-3 100. 150 x 4.6 mm w/ C18 guard column |
λ = 261 nm |
80 % v/v H2O pH=4 (pure acetic acid) + 0.005M ammonium acetate 20 % v/v ACN |
1.2 |
40 |
50 |
|
17 |
Kinetex; RP-C18 150x4.6 mm; 5 µm |
λ = 230 nm |
11/89. MeOH: Buffer (Buffer = 3.0 g KH2PO4 +3.0 g K2HPO4+ 100 mL water) |
0.6 |
40 |
6 |
|
|
18 |
yes |
C18 Luna. Phenomenex |
λ = 224 nm |
95 % phosphate buffer: 5 % ACN |
1.2 |
ambient |
20 |
|
19 |
yes |
Phenomenex Aqua C18 125A 250 x 4.6 mm; 5 µm |
λ = 235 nm |
0.005M ammonium acetate (pH 4): ACN = 8:2 |
1 |
25 |
2 |
|
20 |
yes |
Zorbax Eclipse XDB-C18 4.6 x 150 mm. 5 µm |
λ = 235 nm |
650 mL H2O pH 2 (HCl 0.1M) + 280 mL MeOH + 7 mL THF |
1 |
ambient |
5 |
|
21 |
yes |
RP-18 Nucloedur 100-C18. 3 µm. 50 mm |
λ = 262 nm |
A:B = 80:20; A: ammonium acetate. 0.002 mol/l. pH= 4.1 (adjusted by conc. Acetic acid); B: MeOH/ACN 2:1 |
1 |
60 |
6 |
|
22 |
yes |
HYPERSIL ODS 250X4.6 mm. 5 µm |
λ = 235 nm |
1.8 |
40 |
20 |
|
|
23 |
yes |
RP-C18 . 150 x 4.6 mm; 5 µm |
λ = 235 nm |
1 |
25 |
20 |
|
|
24 |
yes |
RP-C18 Purospher .125 x 4 mm; 5 µm |
λ = 235 nm |
MeOH / 0.02M sodium acetate buffer pH 4.4 = (30/70 v/v) |
0.8 |
40 |
5 |
|
26 |
yes |
Kinetex XB-C18 100 x 4.6 mm; 2.6 µm |
λ = 254 nm |
Water 0.1 % TFA. ACN 0.1 % TFA |
1.5 |
30 |
10 |
TABLE 2 - INDIVIDUAL RESULTS FOR SORBIC ACID (mg/L)
|
White wine (A) |
Rosé (B) |
White Wine (C) |
Red wine (D) |
Fortified wine (E) |
Rosé (F) |
White wine (G) |
White wine (I) |
White wine (K) |
Red wine (M) |
Fortified wine (N) |
White wine(O) |
|||||||||||||
|
Laboratory code |
1 |
2 |
1 |
2 |
1 |
2 |
1 |
2 |
1 |
2 |
1 |
2 |
1 |
2 |
1 |
2 |
1 |
2 |
1 |
2 |
1 |
2 |
1 |
2 |
|
1 |
36.3 |
35.5 |
226.0 |
221.0 |
88.0 |
86.0 |
5.2 |
5.3 |
1.7 |
1.8 |
226,0 |
224.0 |
36.1 |
35.9 |
125.0 |
124.0 |
90.0 |
87.0 |
4.7 |
4.6 |
1.8 |
2.0 |
126.0 |
126.0 |
|
2 |
33.1 |
33.2 |
210.7 |
208.3 |
80.9 |
81.4 |
4.5 |
4.4 |
1.7 |
2.4 |
210.4 |
209.5 |
33.0 |
32.5 |
116.0 |
114.9 |
81.2 |
80.6 |
4.3 |
5.7 |
2.0 |
2.4 |
116.3 |
116.1 |
|
3 |
34.1 |
34.5 |
216.8 |
215.5 |
84.7 |
84.5 |
5.3 |
5.2 |
2.5 |
2.3 |
216.3 |
217.2 |
34.5 |
34.3 |
119.8 |
120.1 |
84.5 |
84.3 |
5.7 |
5.7 |
2.4 |
2.4 |
120.5 |
120.2 |
|
4 |
34.7 |
35.0 |
223.1 |
224.7 |
89.3 |
88.6 |
5.1 |
5.1 |
2.1 |
2.2 |
220.0 |
221.6 |
34.5 |
34.8 |
123.1 |
123.2 |
86.7 |
86.4 |
5.2 |
5.2 |
2.1 |
2.1 |
123.1 |
123.5 |
|
6 |
34.3 |
34.6 |
214.2 |
215.2 |
83.9 |
84.0 |
5.5 |
5.6 |
1.9 |
2.0 |
215.0 |
215.6 |
34.6 |
34.7 |
120.6 |
120.7 |
83.6 |
83.9 |
6.2 |
6.5 |
2.0 |
2.1 |
120.1 |
121.1 |
|
7 |
34,0 |
35.0 |
217.0 |
218.0 |
84.0 |
85.0 |
5.0 |
6.0 |
3.0 |
3.0 |
218.0 |
218.0 |
35.0 |
35.0 |
122.0 |
123.0 |
86.0 |
84.0 |
5.0 |
5.0 |
2.0 |
2.0 |
122.0 |
122.0 |
|
8 |
33.9 |
33.4 |
216.8 |
218.5 |
86.2 |
83.8 |
4.5 |
4.5 |
2.0 |
2.0 |
218.8 |
215.5 |
35.2 |
33.9 |
122.0 |
118.9 |
84.2 |
84.3 |
4.3 |
4.1 |
2.0 |
2.0 |
124.5 |
123.3 |
|
9 |
32.5 |
32.5 |
197.4 |
198.2 |
81.0 |
80.7 |
3.4 |
3.4 |
1.4 |
1.4 |
197.0 |
195.8 |
32.1 |
32.2 |
112.5 |
112.2 |
79.3 |
79.4 |
3.3 |
3.3 |
1.3 |
1.2 |
113.5 |
113.7 |
|
10 |
34.1 |
34.1 |
216.0 |
217.0 |
83.7 |
83.6 |
5.7 |
5.6 |
2.2 |
2.1 |
216.0 |
216.0 |
34.2 |
34.0 |
118.0 |
119.0 |
83.4 |
83.4 |
5.6 |
5.8 |
2.1 |
2.1 |
120.0 |
119.0 |
|
11 |
36.8 |
37.0 |
227.2 |
229.9 |
90.2 |
90.4 |
4.6 |
4.8 |
2.1 |
1.9 |
224.2 |
225.6 |
37.1 |
36.8 |
127.4 |
127.0 |
88.4 |
89.0 |
4.0 |
4.3 |
2.1 |
1.9 |
128.0 |
128.5 |
|
12 |
31.0 |
31.0 |
207.0 |
202.0 |
78.0 |
78.0 |
4.0 |
3.0 |
2.0 |
2.0 |
209.0 |
209.0 |
32.0 |
32.0 |
111.0 |
111.0 |
79.0 |
78.0 |
4.0 |
5.0 |
2.0 |
2.0 |
109.0 |
109.0 |
|
13 |
35.0 |
35.0 |
219.0 |
220.0 |
86.0 |
87.0 |
6.0 |
6.0 |
3.0 |
3.0 |
220.0 |
220.0 |
35.0 |
36.0 |
124.0 |
124.0 |
85.0 |
87.0 |
7.0 |
7.0 |
3.0 |
3.0 |
123.0 |
123.0 |
|
15 |
32.0 |
32.0 |
200.0 |
199.0 |
79.0 |
78.0 |
4.0 |
4.0 |
1.7 |
1.6 |
200.0 |
199.0 |
32.0 |
32.0 |
111.0 |
111.0 |
79.0 |
78.0 |
4.0 |
4.0 |
1.7 |
1.6 |
111.0 |
111.0 |
|
16 |
31.3 |
29.1 |
213.1 |
214.2 |
84.7 |
84.2 |
4.3 |
4.3 |
1.9 |
1.9 |
217.3 |
216,0 |
30.3 |
31.0 |
120.1 |
119.6 |
83.5 |
84.2 |
4.2 |
4.6 |
2.0 |
2.0 |
119.3 |
120.1 |
|
17 |
35.6 |
35.4 |
217.8 |
221.4 |
87.0 |
86.0 |
5.2 |
5.4 |
2.3 |
2.4 |
215.5 |
219.5 |
35.6 |
35.3 |
122.2 |
123.4 |
85.9 |
86.5 |
5.4 |
5.5 |
2.7 |
2.5 |
122.3 |
123.9 |
|
18 |
35.0 |
37.0 |
235.0 |
246.0 |
88.0 |
85,0 |
6.1 |
5.2 |
7.5 |
7.7 |
220.0 |
209.0 |
36.0 |
37.0 |
124.0 |
125.0 |
94.0 |
88.0 |
6.5 |
6.6 |
7.8 |
7.4 |
127.0 |
128.0 |
|
19 |
31.0 |
30.0 |
183.0 |
187.0 |
71.0 |
72.0 |
8.0 |
8.0 |
-2.0 |
0.0 |
177.0 |
179.0 |
30.0 |
27.0 |
105.0 |
106.0 |
67.0 |
71.0 |
4.0 |
5.0 |
-1.0 |
-1.0 |
116.0 |
115.0 |
|
20 |
36.2 |
34.8 |
217.4 |
217.0 |
84.9 |
84.4 |
7.1 |
8.9 |
1.9 |
2.7 |
219.0 |
217.1 |
35.1 |
34.4 |
121.2 |
119.0 |
85.8 |
84.3 |
5.6 |
5.9 |
2.4 |
2.3 |
121.9 |
119.2 |
|
21 |
32.2 |
32.2 |
204.1 |
204.2 |
79.3 |
79.1 |
4.3 |
4.4 |
1.9 |
2.0 |
204.9 |
204.4 |
32.6 |
32.3 |
111.9 |
112.4 |
78.6 |
78.7 |
4.3 |
4.4 |
1.9 |
2.0 |
115.0 |
114.2 |
|
22 |
34.0 |
34.0 |
216.0 |
216.0 |
83.0 |
83.0 |
6.0 |
6.0 |
3.0 |
3.0 |
216.0 |
217.0 |
34.0 |
34.0 |
121.0 |
121.0 |
83.0 |
83.0 |
6.0 |
6.0 |
3.0 |
3.0 |
121.0 |
121.0 |
|
23 |
35.3 |
35.0 |
219.3 |
217.6 |
87.3 |
86.1 |
4.1 |
4.5 |
1.6 |
1.7 |
219.3 |
217.9 |
35.4 |
35.9 |
124.3 |
123.0 |
87.0 |
86.0 |
3.9 |
4.1 |
1.6 |
1.8 |
124.6 |
123.5 |
|
24 |
34.2 |
34.0 |
214.0 |
216.0 |
81.8 |
82.1 |
4.1 |
4.1 |
2.7 |
2.8 |
215.0 |
215.0 |
33.7 |
33.8 |
117.0 |
118.0 |
83.7 |
83.4 |
4.1 |
4.1 |
2.8 |
2.7 |
119.0 |
119.0 |
|
26 |
35.1 |
35.2 |
214.4 |
214.5 |
86.2 |
86.2 |
5.0 |
5.1 |
2.2 |
2.2 |
214.9 |
214.2 |
35.0 |
35.1 |
122.3 |
122.5 |
86.0 |
86.3 |
5.1 |
5.1 |
2.2 |
2.2 |
122.2 |
122.5 |
TABLE 3- RESULTS FOR SORBIC ACID (mg/L)
|
White wine |
Rosé |
White wine |
Red wine |
Fortified wine |
White wine |
|||||||
|
Laboratory code |
A |
G |
B |
F |
C |
K |
D |
M |
E |
N |
I |
O |
|
1 |
35.90 |
36.00 |
223.50 |
225.00 |
87.00 |
88.50 |
5.25 |
4.65 |
1.75 |
1.90 |
124.50 |
126.00 |
|
2 |
33.15 |
32.25 |
209.50 |
209.95 |
81.15 |
80.80 |
4.45 |
5.00 |
2.05 |
2.20 |
115.45 |
116.20 |
|
3 |
34.30 |
34.40 |
216.15 |
216.75 |
84.60 |
84.40 |
5.25 |
5.70 |
2.40c) |
2.40c) |
119.95 |
120.35 |
|
4 |
34.85 |
34.65 |
223.90 |
221.00 |
88.95 |
86.55 |
5.10 |
5.20 |
2.15 |
2.10 |
123.15 |
123.30 |
|
6 |
34.45 |
34.65 |
214.70 |
215.30 |
83.95 |
83.75 |
5.58c) |
6.34 |
1.95c) |
2.08c) |
120.65 |
120.60 |
|
7 |
34.50 |
35.00 |
217.50 |
218.00 |
84.50 |
85.00 |
5.50 |
5.00 |
3.00b) |
2.00b) |
122.50 |
122.00 |
|
8 |
33.65 |
34.55 |
217.65 |
217.15 |
85.00 |
84.25 |
4.50 |
4.20 |
2.00 |
2.00 |
120.45 |
123.90 |
|
9 |
32.49 |
32.16 |
197.83 |
196.38 |
80.81 |
79.40 |
3.42 |
3.32 |
1.41 |
1.25 |
112.38 |
113.56 |
|
10* |
34.10 |
34.10 |
216.50 |
216.00 |
83.65 |
83.40 |
5.66 |
5.68 |
2.15c) |
2.13c) |
118.50 |
119.50 |
|
11* |
36.90 |
36.95 |
228.55 |
224.90 |
90.30 |
88.70 |
4.70 |
4.15 |
2.00c) |
2.00c) |
127.20 |
128.25 |
|
12 |
31.00 |
32.00 |
204.50 |
209.00 |
78.00 |
78.50 |
3.50 |
4.50 |
2.00 |
2.00 |
111.00 |
109.00 |
|
13 |
35.00 |
35.50 |
219.50 |
220.00 |
86.50 |
86.00 |
6.00 |
7.00 |
3.00 |
3.00 |
124.00 |
123.00 |
|
15* |
32.00 |
32.00 |
199.50 |
199.50 |
78.50 |
78.50 |
4.00 |
4.00 |
1.65 |
1.65 |
111.00 |
111.00 |
|
16 |
30.20 |
30.65 |
213.65 |
216.65 |
84.45 |
83.85 |
4.28 |
4.38 |
1.94 |
1.96 |
119.85 |
119.70 |
|
17 |
35.53 |
35.44 |
219.61 |
217.53 |
86.51 |
86.19 |
5.30 |
5.47 |
2.38 |
2.61 |
122.82 |
123.12 |
|
18 |
36.00 |
36.50 |
240.50b) |
214.50b) |
86.50b) |
91.00b) |
5.65 |
6.55 |
7.60a) |
7.60a) |
124.50 |
127.50 |
|
19 |
30.50b) |
28.50b) |
185.00a) |
98.00a) |
71.50a) |
69.00a) |
8.00b) |
4.50c)b) |
-1.00c)a) |
-1.00c)a) |
105.50b) |
115.50b) |
|
20 |
35.50 |
34.75 |
217.20 |
218.05 |
84.65 |
85.05 |
8.00b) |
5.75b) |
2.30c) |
2.35c) |
120.10 |
120.55 |
|
21 |
32.20 |
32.45 |
204.15 |
204.65 |
79.20 |
78.65 |
4.36 |
4.36 |
1.94 |
1.94 |
112.15 |
114.60 |
|
22 |
34.00 |
34.00 |
216.00 |
216.50 |
83.00 |
83.00 |
6.00 |
6.00 |
3.00 |
3.00 |
121.00 |
121.00 |
|
23 |
35.15 |
35.65 |
218.45 |
218.60 |
86.70 |
86.50 |
4.30 |
4.00 |
1.65c) |
1.70c) |
123.65 |
124.05 |
|
24 |
34.10 |
33.75 |
215.00 |
215.00 |
81.95 |
83.55 |
4.10 c) |
4.10c) |
2.75c) |
2.75 c) |
117.50 |
119.00 |
|
26 |
35.13 |
35.06 |
214.45 |
214.58 |
86.21 |
86.15 |
5.07 |
5.07 |
2.17 |
2.17 |
122.37 |
122.35 |
a) Values rejected by Grubbs test on mean outliers
b) Values rejected by Cochran test variance outliers
c) Value identified by the laboratory below Quantification Limit
TABLE 4 - PRECISION DATA
|
Indicators |
White wine (A/G) |
Rosé (B/F) |
White wine (C/K) |
Red wine (D/M) |
Fortified wine (E/N) |
White wine (I/O) |
|
Number of laboratories |
22 |
21 |
21 |
21 |
20 |
22 |
|
Number of repetitions |
2 |
2 |
2 |
2 |
2 |
2 |
|
Minimum (mg/L) |
30.20 |
196.38 |
78.00 |
3.32 |
1.25 |
109.00 |
|
Maximum (mg/L) |
36.95 |
228.55 |
90.30 |
7.00 |
3.00 |
128.25 |
|
Repeatability variance sr2 |
0.0942 |
1.5249 |
0.4191 |
0.1201 |
0.0037 |
0.9397 |
|
Intergroup variance sL2 |
2.6370 |
55.1140 |
9.7049 |
0.6418 |
0.1793 |
22.4914 |
|
Reproducibility variance sR2 |
2.7312 |
56.6389 |
10.1240 |
0.7619 |
0.1830 |
23.4311 |
|
Average (mg/L) |
34.16 |
214.72 |
83.96 |
4.92 |
2.15 |
120.07 |
|
Repeatability standard deviation (mg/L) |
0.31 |
1.23 |
0.65 |
0.35 |
0.06 |
0.97 |
|
Repeatability limit (mg/L) |
0.869 |
3.495 |
1.832 |
0.981 |
0.172 |
2.743 |
|
Repeatability RSD % |
0.9 |
0.6 |
0.8 |
7.0 |
2.8 |
0.8 |
|
Reproducibility standard deviation (mg/L) |
1.65 |
7.53 |
3.18 |
0.87 |
0.43 |
4.84 |
|
Reproducibility limit (mg/L) |
4.677 |
21.298 |
9.005 |
2.470 |
1.211 |
13.699 |
|
Reproducibility RSD % |
4.8 |
3.5 |
3.8 |
17.7 |
19.9 |
4.0 |
|
HORRAT |
0.5 |
0.5 |
0.5 |
1.4 |
1.4 |
0.5 |
FIGURE 1 – CORRELATION BETWEEN SORBIC ACID CONCENTRATION AND PRECISION
 |
FIGURE 2 - Z-SCORES REPRESENTATION WITHOUT OUTLIERS
 |
*LAI -lower action limit; LAS - upper action limit; LSI - lower warning limit; LSS - upper warning
[1] For sorbic acid analysis the column and the wavelength are given as an example.