Mattern G C, Singer G M, Louis J, Robson M, Rosen J D
Rutgers University, Cook College, Department of Food Science, New Brunswick, NJ 08903.
J Assoc Off Anal Chem. 1989 Nov-Dec;72(6):970-4.
A convenient method for the determination of the N-methyl,N-methoxy-phenylurea herbicide (linuron) in potatoes has been developed. The herbicide is extracted from potatoes using a slightly modified Luke multiresidue procedure. The extract is analyzed directly by gas chromatography with cold on-column injection, using an ion trap mass spectrometer in the chemical ionization mode as the detector. Quantitation is performed using p-bromonitrobenzene as the internal standard. The limit of detection is 0.1 ppm. Recoveries of linuron in potatoes averaged 112 +/- 6% at the 0.5 ppm level, and 110 +/- 2% at the 0.2 ppm level. No linuron residues were found in 25 potato samples that were analyzed by this method. Two other N-methyl,N-methoxy-phenylurea herbicides, metobromuron and chlorbromuron, are also sufficiently stable to be determined by this method, but the N,N-dialkyl-phenylurea herbicides neburon, diuron, and monuron are too thermally unstable and degrade in the gas chromatograph.
已开发出一种测定马铃薯中N-甲基，N-甲氧基苯基脲类除草剂（利谷隆）的简便方法。采用略有改进的卢克多残留方法从马铃薯中提取该除草剂。提取物通过冷柱头进样气相色谱直接分析，使用化学电离模式的离子阱质谱仪作为检测器。使用对溴硝基苯作为内标进行定量。检测限为0.1 ppm。利谷隆在马铃薯中的回收率在0.5 ppm水平时平均为112±6%，在0.2 ppm水平时平均为110±2%。用该方法分析的25个马铃薯样品中未发现利谷隆残留。另外两种N-甲基，N-甲氧基苯基脲类除草剂，甲氧隆和氯溴隆，也足够稳定，可以用该方法测定，但N，N-二烷基苯基脲类除草剂绿谷隆、敌草隆和灭草隆热稳定性太差，会在气相色谱仪中降解。
