Enzymatic method for the determination of acetic acid. Based on the spectrophotometric measurement of NADH produced through the reactions, after addition of Acetyl-Co A synthetase (ACS), Citrate synthase (CS) and L-malate dehydrogenase (L-MDH).
Acetic acid is a very important metabolite since it is the end product of fermentation processes and the oxidation product of acetaldehyde and ethanol. Acetic acid is the main component of the "volatile acids" in wine and one of the most important parameters of its quality control. A high concentration of acetic acid in wine results in spoilage of the product. Thus, there may be legal limitations in the acetic acid content. Acetic acid is used in food production as a preservative and a taste improver. Acetic acid is the compound determining the monetary value of vinegar.
This rapid and simple specific enzymatic method is used for the determination of acetic acid (acetate) in foodstuffs such as wine, vinegar, beer, dairy products, bread, fruit, fish, meat and vegetable, as well as in paper, animal feed (silages), pharmaceuticals and biological samples.
Solution 1. TEA buffer (30 mL, 0.8 M, pH 8.4), L-malic acid (60 mM), MgCl2 (20 mM) and sodium azide (0.02% w/v) as a preservative. Stable for 2 years at 4 °C. Solution 2 (x2). NAD+ (67 mg), ATP (137 mg), PVP (30 mg) and CoA (9.8 mg). Stable for 2 years at -20 °C. Dissolve in 5.5 mL of distilled water, divide into appropriately sized aliquots and store in PP tubes at -20 °C between use (stable for 2 years) and keep cool during use. The content of the second bottle should be dissolved only when required. Suspension 3. L-Malate dehydrogenase (L-MDH, 950 U/mL) and citrate synthase (CS, 112 U/mL) in 3.2 M ammonium sulphate (1.1 mL). Stable for 2 years at 4 °C. Suspension 4. Acetyl-CoA synthetase (ACS, 290 U/mL) in 3.2 M ammonium sulphate (1.1 mL). Stable for 2 years at 4 °C. Solution 5. Acetic acid standard solution (5 mL, 0.10 mg/mL). Stable for 2 years at 4 °C. This standard can be used when there is doubt about the method accuracy (NADH,340 nm = 6300 L×mol-1×cm-1).
Compatible Sample Types:
Wine, beer, vinegar, fish, meat, fruit and vegetables, dairy products, animal feed (silages), pharmaceuticals and biological samples.
Features & Benefits:
Stable ACS suspensionPrevention of tanins inhibition (PVPP included)
Reaction volume: 2.84 mLRange: 0.15-200 mg/LDetection limit: 0.14 mg/L