Determination of Free (pH 2.2) Sulfite in Wines by Flow Injection Analysis: Collaborative Study

Abstract A method for the determination of free sulfite In wine by flow injection analysis (FIA) is described. The method Involves liberation of sulfur dioxide from the wine at pH 2.2, with detection by decolorlzation of a malachite green solution. The method was collaboratively studied, and the results indicated an average reproducibility of 12% for white wine samples (average level 12.1 ppm S02) and 26% for red wine samples (average level 3.1 ppm). When the FIA method was compared to an aeration/oxidation method, the results Indicated a high degree of correlation between the 2 methods. The FIA method has been adopted by AOAC official first action.

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Determination Of Total Sulfite In Shrimp, Potatoes, Dried Pineapple, And White Wine By Flow Injection Analysis: Collaborative Study

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/73.1.35 ◽

1990 ◽

Vol 73 (1) ◽

pp. 35-42 ◽

Cited By ~ 2

Author(s):

John J Sullivan ◽

Thomas A Hollingworth ◽

Marleen M Wekell ◽

Victor A Meo ◽

Haytham H Saba ◽

...

Keyword(s):

Malachite Green ◽

Flow Injection ◽

Flow Injection Analysis ◽

Collaborative Study ◽

White Wine ◽

Gas Diffusion ◽

Sample Solution ◽

Green Is ◽

Teflon Membrane

Abstract A method for the determination of total sulfite in shrimp, potatoes, dried pineapple, and white wine by flow injection analysis (FIA) was collaboratively studied by 8 laboratories. In the method, the sample solution Is reacted with sodium hydroxide to liberate aldehyde-bound sulfite. The sample stream is acidified to produce S02 gas, which diffuses across a Teflon membrane in the gas diffusion cell into a flowing stream of malachite green. The degree of discoloration of the malachite green is proportional to the amount of sulfite in the sample solution. Red wine was included in the study but Interlaboratory precision for these samples was not satisfactory and correlation with Monier-Williams results was poor. The present method is not recommended for use with these samples. For shrimp, potatoes, dried pineapple, and white wine, average reproducibility (RSDR) of results was 25% for samples at 10 ppm S02 and 10% for samples at >50 ppm. Overall average reproducibility was 14%. Recoveries of sulfite added to samples averaged 80%. Comparison of FIA with the Monier-Williams method indicated comparable results by the 2 methods. The FIA method has been adopted official first action for determination of ≥5 ppm total sulfite in shrimp, potatoes, dried pineapple, and white wine.

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Determination of Total Carbohydrates in Wine and Wine-Like Beverages by HPLC with a Refractive Index Detector: First Action 2013.12

Journal of AOAC International ◽

10.5740/jaoacint.13-320 ◽

2014 ◽

Vol 97 (2) ◽

pp. 498-505 ◽

Cited By ~ 2

Author(s):

Steve Kupina ◽

Mark Roman ◽

D Anderson ◽

S Bhandari ◽

M S Cardozo ◽

...

Keyword(s):

Refractive Index ◽

Reference Material ◽

Organic Acids ◽

Red Wine ◽

Collaborative Study ◽

Ion Exchange Resin ◽

White Wine ◽

Negative Control ◽

Total Carbohydrates

Abstract An international collaborative study was conducted of an HPLC-refractive index (RI) detector method for the determination of the combined amounts of sugars, glycerol, organic acids, and phenolic compounds in wines and wine-like beverages. Nine collaboratinglaboratories representing major winery, contract laboratories, and government laboratories tested eight different materials as blind duplicates using the proposed method. Sample materials included red and white wines, port, wine cooler, and nonalcoholic wine. One material was a negative control, and one material was a reference material. Samples were either treated with an ion-exchange resin to remove interferingorganic acids prior to analysis or left untreated toinclude organic acids and phenolics. Red wine samples were treated with polyvinylpolypyrrolidone to remove potential interferences from phenolics prior to analysis. The HPLC analyses were performed on a Bio-Rad Fast Acid Analysis Column using RI detection. Reproducibility (RSDR) for untreated samples(sugars + phenolics + organic acids) ranged from 6.6% for Titrivin AA4 reference material to 11.0% for dry red wine. RSDR for treated samples (sugars only) ranged from 6.8% for white zinfandel to 18.9% for dry white wine. RSDR for treatedsamples (sugars only) + glycerol ranged from 6.4% for white zinfandel to 19.8% for dry red wine. Based on these results, the method was adopted as Official First Action status for determination of total carbohydrates in wine and wine-like beverages.

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Determination of Ochratoxin A in Wine and Beer by Immunoaffinity Column Cleanup and Liquid Chromatographic Analysis with Fluorometric Detection: Collaborative Study

Journal of AOAC International ◽

10.1093/jaoac/84.6.1818 ◽

2001 ◽

Vol 84 (6) ◽

pp. 1818-1827 ◽

Cited By ~ 70

Author(s):

Angelo Visconti ◽

Michelangelo Pascale ◽

Gianluca Centonze ◽

E Anklam ◽

A M Betbeder ◽

...

Keyword(s):

Ochratoxin A ◽

Red Wine ◽

Collaborative Study ◽

White Wine ◽

Fluorometric Detection ◽

Immunoaffinity Column ◽

Relative Standard ◽

Standard Deviations ◽

Liquid Chromatographic

Abstract The accuracy, repeatability, and reproducibility characteristics of a liquid chromatographic method for the determination of ochratoxin A (OTA) in white wine, red wine, and beer were established in a collaborative study involving 18 laboratories in 10 countries. Blind duplicates of blank, spiked, and naturally contaminated materials at levels ranging from ≤0.01 to 3.00 ng/mL were analyzed. Wine and beer samples were diluted with a solution containing polyethylene glycol and sodium hydrogen carbonate, and the diluted samples were filtered and cleaned up on an immunoaffinity column. OTA was eluted with methanol and quantified by reversed-phase liquid chromatography with fluorometric detection. Average recoveries from white wine, red wine, and beer ranged from 88.2 to 105.4% (at spiking levels ranging from 0.1 to 2.0 ng/mL), from 84.3 to 93.1% (at spiking levels ranging from 0.2 to 3.0 ng/mL), and from 87.0 to 95.0% (at spiking levels ranging from 0.2 to 1.5 ng/mL), respectively. Relative standard deviations for within-laboratory repeatability (RSDr) ranged from 6.6 to 10.8% for white wine, from 6.5 to 10.8% for red wine, and from 4.7 to 16.5% for beer. Relative standard deviations for between-laboratories reproducibility (RSDR) ranged from 13.1 to 15.9% for white wine, from 11.9 to 13.6% for red wine, and from 15.2 to 26.1% for beer. HORRAT values were ≤0.4 for the 3 matrixes.

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