Mizuishi K, Takeuchi M, Hobo T
Tokyo Metropolitan Research Laboratory of Public Health, Japan.
J Chromatogr A. 1998 Mar 27;800(2):267-73. doi: 10.1016/s0021-9673(97)01153-9.
An analytical gas chromatography-mass spectrometry (GC-MS) method using negative ion chemical ionization (NICI) has been investigated for the determination of trace tributyltin (TBT) and triphenyltin (TPhT) compounds in sea water. TBT and TPhT were extracted from samples as chloride under the acidic condition of HCl. Doping of the GC system with a dilute HBr-methanolic solution resulted in direct detection of the chlorides of TBT, TPhT and tripentyltin (TPenT, internal standard). As the result of HBr doping, a sharp peak of the respective organotin bromides appeared: during GC analysis, halogen exchange from the chloride to the bromide occurred. NICI-MS was highly selective and sensitive for the detection of TBT. TPhT and TPenT bromides. In the selected ion monitoring mode of NICI-MS, the minimum detectable amounts defined as the signal equal to three times the standard deviation (3 sigma) of the baseline noise were 20 and 25 pg ml-1 for TBT and TPhT, respectively. These amounts are approximately 250-400 times better than those in electron impact mode. The combination of GC using an apolar capillary column doped with a dilute HBr-methanolic solution and NICI-MS made it possible to determine TBT and TPhT at less than the ng l-1 level in sea water.
已研究了一种采用负离子化学电离（NICI）的分析气相色谱 - 质谱（GC - MS）方法，用于测定海水中的痕量三丁基锡（TBT）和三苯基锡（TPhT）化合物。在盐酸的酸性条件下，TBT和TPhT以氯化物形式从样品中萃取出来。向GC系统中加入稀HBr - 甲醇溶液可直接检测TBT、TPhT和三戊基锡（TPenT，内标）的氯化物。由于加入了HBr，各自的有机锡溴化物出现了尖锐的峰：在GC分析过程中，发生了从氯化物到溴化物的卤素交换。NICI - MS对TBT、TPhT和TPenT溴化物的检测具有高选择性和高灵敏度。在NICI - MS的选择离子监测模式下，定义为信号等于基线噪声标准偏差三倍（3σ）的最低检测量，TBT和TPhT分别为20和25 pg ml-1。这些量比电子轰击模式下的量约好250 - 400倍。使用填充有稀HBr - 甲醇溶液的非极性毛细管柱的GC与NICI - MS相结合，使得能够测定海水中低于ng l-1水平的TBT和TPhT。
