Investigation On The Potential Adulteration Determination Method Of Cognac Based On The Technique Of Gas And Liquid Chromatography

Brandy is one of the well-known distilled liquor in the world and widely favored by the peoples of the world.Brandy brewing spread all around the world,especially the brandies from Cognac area,France are widely recognized as the superior products.Because of the high price of brandy,but the low cost of liquor making,the profits of making faked brand brandy are significantly high which results in the market glutted with adulterated brandy.Its severity has attracted more and more attention,especially the wine management department.Therefore,it is urgent to develop the available methods to identify the authenticity of brandy sold in the market.The study firstly determined the three kinds of characteristic volatile substances,including esters,aldehydes and higher alcohols,in three brands,eleven grades of Cognac Brandies including Remy Martin,Hennessy,and Martell using gas chromatography,and the precision and reproducibility of the method were also investigated.The results showed that the determination of the three groups of volatile substances in Cognac Brandies using the gas chromatography was reliable.The determination results found that the contents of these three groups of volatile substances including esters,aldehydes and higher alcohols in different brands and grades had significant differences.Therefore,this method was variable for authentication identification of faked Cognac Brandy.Fourteen faked brandies were found in 210 samples including three brands,eleven grades of Remy Martin,Hennessy,and Martell Cognac Brandies marketed in Guangdong Province based on the contents of esters,aldehydes and higher alcohols and the Characteristic concentration level of gas chromatography.Because the contents of esters,aldehydes and higher alcohols in Cognac Brandy were just available for authentication identification.Therefore,the study developed a liquid chromatography-diode array method to simultaneous determined ten aromatic hydrocarbons chemicals including gallic acid,5-hydroxymethylfurfural,vanillic acid,syringic acid,5-methyl furfural,vanillic aldehyde,syringaldehyde,coniferyl aldehyde,and mustard aldehyde.The conditions of the method were also optimized and the optimal conditions of liquid chromatography were: detection wavelength 280 nm,gradient elution,mobile phase 10% acetonitrile aqueous solution(0.1 % acetic acid),(C): 90 % acetonitrile aqueous solution(0.1% acetic acid)(D)= 100 :0(adjust pH to 3 using acetic acid),flowing rate 0.8 m L/min,run time(min): 3.5,4.6,25,26,35,50,C(%): 100,90,85,40,100,100,column temperature 40 °C.The results of methodological investigation showed that the determination method had good precision and accuracy when it was employed to measure the concentration levels of 10 aromatic hydrocarbons chemicals in Cognac Brady using liquid chromatography-diode array method.Total 205 Cognac Brandy consisting of Remy Martin,Hennessy,and Martell in different grades were detected the concentrations of 10 aromatic hydrocarbons chemicals,and the evaluation criteria was established to identify the grades and authentication.The adulterated identification and grade evaluation were feasible for Remy Martin,Hennessy,and Martell using the content of the three groups of esters,aldehydes and higher alcohols and the concentration levels of 10 aromatic hydrocarbons chemicals.