气相色谱法对水果样品中三碘苯甲酸残留的测定

分别选取了苹果、梨等6种水果基质,样品经1%硫酸酸化,用二氯甲烷提取,提取液蒸干后用三甲基硅重氮甲烷进行甲酯化衍生,经弗罗里硅土固相萃取柱净化后上机测定.采用气相色谱,程序升温,电子捕获检测器测定,保留时间定性,外标法定量.优化了衍生条件,并对方法的灵敏度、准确度、精密度和回收率进行了实验,三碘苯甲酸的检出限可达0.000 8 mg/kg,方法在0.01 ～20 mg/L范围内线性关系良好.各浓度水平的添加回收率为63% ～107%,相对标准偏差为1.8% ～9.3%.建立的方法符合国家标准对食品中农药残留测定的要求,可用于对食品安全的监测.

Determination of Residues of 2,3,5-Triiodobenzoic Acid in Fruit Samples by Gas Chromatography method

A method was developed for separation and determination of 2, 3, 5-triiodobenzoic acid (T1BA) in fruits samples by gas chromatography (GC) with electron capture detector. The fruits samples was extracted with methylene chloride after acidification with 1% sulfuric acid. The extract was methylated with (trimethylsilyl) diazometha, and then cleaned up with a florisil solid phase extraction (SPE) column. The confirmation of TTBA was performed by using retention time, and the quantitative analysis of TIBA was carried out by external standard method. The result indicated that the calibration curve was linear in the range of 0. 01 -20 mg/L for TIBA concentration with a detection limit of 0. 000 8 mg/kg. The spiked recoveries ranged from 63% to 107% with RSDs of 1. 8% -9. 3% . The method met the requirement of the national standard for determination of pesticide residues in food,and could used for monitoring food safety.