METHOD FOR DETECTION OF ETHANOL OF NON-GRAPES ORIGIN IN GRAPE DISTILLATES AND DRINKS ON THEIR BASIS Russian patent published in 2010 - IPC G01N33/14 

FIELD: food industry.

SUBSTANCE: sample is distilled at the temperature of 50, 78 and 90°C. Aliquots of distilled fractions of distillate are placed into ampoules, where oxidised copper oxide is previously placed, frozen, ampoules are vacuumised and sealed. Aliquot of each fraction is burnt to produce carbon dioxide, which is quantitatively collected and exposed to isotopic mass spectrometric analysis. In process of analysis, currents provided by quantity of ions with m/z 44(¹²C¹⁶O₂ ⁺), m/z 45(¹³C¹⁶O₂ ⁺) and m/z 46(¹²C¹⁶O¹⁸O) are alternately registered in mass spectra of carbon dioxide sample and laboratory standard. Characteristics of isotopic composition of carbon dioxide produced when each fraction of distillate is burnt, relative to international carbon standard V-PDB, are defined in relative units δ¹⁶C (‰), using formula, included into software for mass-spectrometer Delta V plus Thermo Finnigan, of the following type: δ¹³C=(R_s/R_st-1)·1000(‰), where R_s=([¹³C¹⁶O₂]/[¹²C¹⁶O₂])_s, R_st=([¹³C¹⁶O₂]/[¹²C¹⁶O₂])_st, R_s and R_st - ratios of abundances of stable isotopes ¹³C and ¹²C in analysed carbon dioxide, produced when fraction of distillate and standard are burnt. Isotopic characteristics of carbon composition are defined in reference samples produced using available samples of ethanol. Produced ratios of abundances of stable isotopes ¹³C and ¹²C are compared to each other and to characteristics of reference sample, and extent of match or deviation is used to justify origin of ethanol. Difference in values of quantitative isotopic characteristics of carbon in all fractions of distillate that exceeds 0.5‰ is used to detect availability of ethanol of non-grape origin in sample.

EFFECT: increased accuracy and validity of method.

2 tbl, 6 ex