Liquor Testing

Zhu, Xiaochun, Shuang Chen, and Yan Xu. Food Control 140 (2022): 109101.

Non-glycosidic cyanogens present in sorghum, wheat, and fermented grains during the fermentation process of Chinese liquor can easily decompose and release toxic cyanide ions, affecting the quality and safety of liquor and potentially posing a threat to public health.

In this study, a simple and practical method for determining non-glycosidic cyanogens was developed using QuEChERS sample preparation combined with spectrophotometry. The recovery rates of analytes in spiked samples were optimized by adjusting the QuEChERS extraction solvent, buffer solution, and SPE adsorbent. Under optimal conditions, the linear range for cyanide determination was 0.02–0.44 μg/mL, with a correlation coefficient of 0.99 and a limit of detection (LOD) of 0.0023 μg/mL. The recoveries of spiked samples (82.11–115.12%) and relative standard deviations (RSD; 4.87–9.62%) were considered satisfactory.

Somboon, Titikan, et al. LWT 154 (2022): 112593.

To ensure the quality and authenticity of beverage products, it is necessary to assess the ethanol content in alcoholic drinks.

A simple and environmentally friendly method for the quantitative determination of ethanol concentration is introduced, based on conductivity measurements and a non-catalytic esterification reaction. The reaction progress between ethanol and acetic acid is monitored by measuring conductivity, which corresponds to the amount of hydrogen ions and acetate anions produced by the dissociation of acetic acid. By fixing the concentration of acetic acid, a decrease in conductivity was observed as ethanol concentration increased. A successful inverse linear relationship between conductivity and ethanol concentration in the range of 0.0-99.9% v/v was established. This method allows for the effective quantification of ethanol content with good intra- and inter-day precision (RSD < 3.45%). The method has been successfully applied to determine ethanol concentration in alcoholic beverage samples and validated using gas chromatography.

Han, Y., Song, L., Liu, S., Zou, N., Li, Y., Qin, Y., ... & Pan, C. (2018). Food Chemistry, 241, 258-267.

Liquor is one of the oldest distilled spirits in the world, typically made from grains, with sorghum as a primary ingredient. However, in modern agriculture, due to the occurrence of pests, diseases, and weeds, large amounts of pesticides are inevitably used during the sorghum growing process to ensure high yield and quality. This can lead to pesticide residues in sorghum, which may transfer into liquor, posing potential risks to human health. Therefore, monitoring pesticide residues in liquor and its brewing raw materials (sorghum and rice husks) is crucial for human health.

A multi-residue analytical method was developed for the determination of 124 pesticide residues in Chinese liquor and brewing raw materials (sorghum and rice husks) using rapid multi-plug filtration cleanup (m-PFC) and GC-MS/MS detection. The dispersive solid-phase extraction (d-SPE) procedure was optimized for each matrix by adjusting different combinations and ratios of adsorbents. The 124 pesticides exhibited good linearity with regression coefficients (R²) greater than 0.9901. Except for cycloprothrin, pyraclonil, and prothioconazole, the average recoveries for the other 121 pesticides ranged from 71% to 121%, with relative standard deviations (RSD) below 16.8%. The limits of quantification (LOQ) for the 124 pesticides in the matrices ranged from 1.0 × 10^-4 to 5.0 × 10^-3 mg/kg, and the limits of detection (LOD) ranged from 3.0 × 10^-5 to 1.5 × 10^-3 mg/kg. The results demonstrated that the m-PFC procedure is superior to the d-SPE method and can be used for routine monitoring of pesticide residues in market samples.