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分别采用电子轰击电离(EI)源和正化学电离(PCI)源两种离子源技术建立了气相色谱-质谱(GC-MS)同时测定白菜和苹果中苯丁锡、三苯锡和三环锡含量的方法,并对这两种方法进行了比较。样品经氢溴酸消解、丙酮-正己烷(1∶2,v/v)提取,四乙基硼化钠衍生后用Florisil固相萃取柱净化,分别在EI源和PCI源下以选择离子监测模式进行测定。结果表明,方法的检出限(S/N=3)分别为0.01~0.05 mg/kg(EI源)和0.01~0.02 mg/kg(PCI源),定量限(S/N=10)分别为0.03~0.16 mg/kg(EI源)和0.02~0.06 mg/kg(PCI源)。三苯锡、三环锡和苯丁锡分别在各自的线性范围内线性关系良好,相关系数(r~2)≥0.997。在50、100、200μg/kg 3个添加水平下,采用GC-EI/MS和GC-PCI/MS时,阴性样品中3种有机锡的平均回收率分别为59.24%~97.36%(苹果)、50.54%~94.54%(白菜)和65.38%~95.86%(苹果)、62.56%~90.44%(白菜),相对标准偏差(RSD)均不超过6.9%(n=6)。该方法简单、灵敏,PCI源的选择性优于EI源,两种方法可以相互结合提高检测结果的可靠性。
Gas chromatography-mass spectrometry (GC-MS) was developed for simultaneous determination of dibutyltin, triphenyltin and tricyclic tin in Chinese cabbage and apple by ion bombardment (EI) and positive ionization (PCI) Method, and compared these two methods. Samples were digested with hydrobromic acid, extracted with acetone-n-hexane (1: 2, v / v), derivatized with tetraethyl sodium boride and cleaned up using a Florisil solid phase extraction column with selective ion monitoring Mode for determination. The results showed that the limit of detection (S / N = 3) was 0.01-0.05 mg / kg (EI source) and 0.01-0.02 mg / kg (PCI source) 0.03 to 0.16 mg / kg (EI source) and 0.02 to 0.06 mg / kg (PCI source). Triphenyltin, tricyclotine and dibenzyl tin in a good linear relationship within their respective linear range, the correlation coefficient (r ~ 2) ≥ 0.997. The average recoveries of the three organotin compounds in the negative samples were 59.24% -97.36% (apple) at GC-EI / MS and GC-PCI / MS at the three levels of 50, 100 and 200μg / The relative standard deviations (RSDs) of 50.54% ~ 94.54% (cabbage) and 65.38% ~ 95.86% (apples) and 62.56% ~ 90.44% (cabbage) did not exceed 6.9% (n = 6). The method is simple and sensitive, the selectivity of PCI source is better than EI source, and the two methods can be combined to improve the reliability of the detection results.