Barceló D, Maris F A, Geerdink R B, Frei R W, de Jong G J, Brinkman U A
J Chromatogr. 1987 May 8;394(1):65-76. doi: 10.1016/s0021-9673(01)94160-3.
Positive and negative chemical ionization (PCI and NCI, respectively) have been used for the characterization of ten organophosphorus pesticides in on-line liquid chromatography-mass spectrometry (LC-MS). LC analyses were performed on a 20 cm X 0.7 mm I.D. C8-bonded phase using acetonitrile-water (70:30) or acetonitrile-water-chloroacetonitrile (69:30:1) as eluent. With PCI, molecular weight information was obtained with both eluents. For NCI considerable differences in the spectra were found using the two eluents. Without chloroacetonitrile the spectra were dominated by the functional group fragment and with chloroacetonitrile the base peak was [M - R]- with R being methyl or ethyl, while the spectra further contained the functional group ions. Special emphasis was devoted to the occurrence of chloride attachment at different source temperatures. With several compounds the [M + Cl]- ion was formed and its relative intensity strongly increased when the source temperature decreased. With NCI the sensitivity was about one order of magnitude better than with PCI. This advantage was partly lost when 1% of chloroacetonitrile was used in the eluent; on the other hand, complementary structural information was obtained. As an application, the determination of three organophosphorus pesticides in sediment is reported.
正化学电离和负化学电离（分别为PCI和NCI）已用于在线液相色谱-质谱联用（LC-MS）中十种有机磷农药的表征。液相色谱分析在一根20 cm×0.7 mm内径的C8键合相柱上进行，使用乙腈-水（70:30）或乙腈-水-氯乙腈（69:30:1）作为洗脱剂。采用PCI时，两种洗脱剂均能获得分子量信息。对于NCI，使用这两种洗脱剂时在光谱上发现了相当大的差异。不使用氯乙腈时，光谱以官能团碎片为主；使用氯乙腈时，基峰为[M - R]-，其中R为甲基或乙基，而光谱中还包含官能团离子。特别关注了在不同源温度下氯附着的情况。对于几种化合物，形成了[M + Cl]-离子，且当源温度降低时其相对强度显著增加。使用NCI时的灵敏度比使用PCI时约高一个数量级。当洗脱剂中使用1%的氯乙腈时，这一优势部分丧失；另一方面，获得了互补的结构信息。作为应用实例，报道了沉积物中三种有机磷农药的测定。
