Analysis of nitrate compounds and N-nitrosamines in mustard pickles separately by high performance liquid chromatography and supercritical fluid extraction with gas chromatography-thermal energy analyzer

• Main Authors: Meei-Jiuan Bai, 白美娟
• Other Authors: Yuan-Tay Shyu
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/16679835609277738956

碩士 === 國立臺灣大學 === 園藝學研究所 === 89 === ABSTRACT A simple C18 reverse-phase high performance liquid chromatographic method (HPLC) with ultraviolet detector was developed for simultaneous determination of nitrate and nitrite in mustard pickle. The method made use of slightly alkaline solution for extraction, C18 cartridge for clean-up, 0.010 M octylammonium orthophosphate of 20 % aqueous methanol (pH 7.0±0.02) as mobile phase and UV 213 nm for detection. The average recoveries of nitrate and nitrite spiked to samples were 98.8∼100.5% and 95.4∼101.8%. The coefficients of variation were 0.9∼3.4% and 1.2∼4.5%, respectively. The detection limits both were 0.001μg/g。 A carbon dioxide supercritical fluid extraction (SFE) with gas chromatography-thermal energy analyzer (GC-TEA) was developed for simultaneous determination of N-nitrosamines in mustard pickle. The chosen SFE conditions were 60℃, 6000 psi, 5% ethanol modifier, 5 mins static time, dynamic extraction with 25 mL of CO2 in flow rate 1.5 mL/min, 45℃ and collection in 5 mL dichloromethane. The Stabliwax capillary column was required for gas chromatography-thermal energy analyzer。The average recoveries of NMEA, NDEA, NDBA, NPIP, NPYR and NMOR spiked to samples were greater than 90%, except NDMA was 83.4%. The coefficients of variation were below 13%. The detection limits of method were 5 ng/g。 The quantitative results of average content of nitrate and nitrite in 20 mustard pickles were 701.6 and 23.0μg/g, in 10 mustards were 4716.9 and 13.6 μg/g. N-nitrosamines were not detected in 20 mustard pickles.