The HI83740-20 reagents are a high-quality, pre-measured set designed for the rapid and accurate colorimetric determination of copper. These reagents are formulated to work seamlessly with the compatible HI83740 photometer to provide precise copper analysis in wine samples. The test method is straightforward: simply add the specified amounts of Copper Reagents A, B, C, and D to your sample, and a reaction will occur, producing a purple coloration. The intensity of this purple color is directly proportional to the copper concentration. The HI83740 photometer measures this color intensity and displays the results in mg/L. This reagent kit is suitable for samples with an expected copper concentration ranging from 0.00 to 1.50 mg/L.
Grapes naturally accumulate only minimal amounts of copper from the soil. Therefore, elevated copper levels in wine are typically a result of contamination during post-fermentation processing, often from contact with non-stainless steel equipment or impurities in fining agents. The copper content in finished wine is usually very low, generally ranging from 0.10 to 0.30 mg/L, because excess copper is naturally adsorbed and precipitated by yeast cells during fermentation, which can reduce the initial concentration by up to 89%. While small amounts of copper can catalyze oxidation reactions, it is critical to monitor its concentration. Levels exceeding 9 mg/L are metabolically toxic and can inhibit or delay fermentation, and concentrations above 1 mg/L can be sensorially detected, affecting the wine's taste. High copper content can also lead to the formation of a white haze in white wines, which can later form a reddish-brown amorphous precipitate known as 'copper casse.' This precipitation only occurs under the highly reducing conditions found in bottled wine and is a complex mixture of copper compounds and proteins.
