Papers by Author: Xin Hua Zhang

Abstract: A Reversed-Phase High Performance Liquid Chromatographic method was developed for determining free Amino Acids in Burley Tobacco. The test was done by OPA/3-mercaptopropionic Acid as the pre-column derivatising reagent. Chromatographic column was Elitte C₁₈ column (4.6mm×250mm i.d., 5um). Mobile phase A was 18mmol/L NaAc (PH=7.2) including 0.002% (v/v) triethylamine and 0.3% (v/v) furanidine. Mobile phase B was 100 mmol/L NaAc (PH=7.2) -Acetonitrile- methanol (v/v=1:2:2). The column temperature was 40°C and the flow rate was 1.0ml/min. The fluorescence detector was used with 350nm excitation wave length and 450nm emission wave length. The average recoveries of the method ranged 95.3% to 100.7% with the relative standard deviation of 2.32%~9.24%. The method is simple, accurate and has good repeatability. The results of the determination of seventeen kinds of free amino acids in burley leaves which were produced by way of different ratio of cake fertilizer and inorganic fertilizer. The results show that aspartic acid has the highest content however ratio of cake fertilizer and inorganic fertilizer. The most contents of free amino acids are increased and then gradually decreased with the increase of organic manure. The most contents of free amino acids are very close at the ratio of 15%:85% ratio and 30%:70% between cake fertilizer and inorganic fertilizer. The total content of free amino acids is the highest at the ratio of 30%: 70% between cake fertilizer and inorganic fertilizer. Considering comprehensively, the quality of burley leaves is the best at the ratio of 30%:70% between cake fertilizer and inorganic fertilizer.

Abstract: Inder order to determine Benzopyrene (BaP) in Mainstream and Sidestream Smoke, a Solid phase extraction (SPE) cartridge was used to isolate the BaP fraction from the total particulate matter of mainstream cigarette smoke and sidestream cigarette smoke and the BaP were measured by RP-HPLC with ultraviolet detection. The result showed that the recovery rate of BaP extracted is 94.5%, compared with the relative standard of 6.95%. The yields of BaP in mainstream smoke for Virginia cigarette are higher than those for blended cigarettes. The yields of BaP in sidestream smoke are much higher than those in mainstream smoke. The proposed method involves an solid phase extract and HPLC-UV analysis procedure. With this method, the BaP yields in mainstream and sidestream cigarette smoke can be measured fast, easily and precisely using readily available apparatus and instruments.