Abstract LC–MS/MS analytical performance characteristics of chloride adduct ions [M + Cl]− of thiamphenicol (TAP) and florfenicol (FFC) as precursor ions for quantification were studied. The calculations were based on a THF/Water solvent system to which dichloromethane was added as an additive at a composition of 2 % to generate chloride (Cl−) ions during electrospray ionization (ESI) of the solutions. The selectivity and signal to noise (S/N) ratio when the [M + Cl]− adduct ions were used as precursor ions were excellent compared to deprotonated [M−H]− ions that are traditionally used to determine the two analytes. The S/N ratios in the total ion chromatogram (TIC) of TAP and FFC were 577 and 3062 respectively, compared to 167 and 452 when [M−H]− were used at the same spike levels of 50 and 100 μg/kg respectively. The limits of detection (LODs) for TAP and FFC were 4.0 and 3.7 μg/kg respectively using [M + Cl]− as opposed to 2.1 and 4.3 μg/kg respectively when [M−H]− were used. [M + Cl]− adduct ions proved to be excellent substitutes for [M−H]− especially where identity and selectivity would be the key drivers of the analytical method before quantification of the two analytes.

中文翻译：

---

氯化物加合物串联质谱法定量牛肌肉中的噻吩苯尼考和氟苯尼考

摘要 研究了作为定量前体离子的噻吩尼考 (TAP) 和氟苯尼考 (FFC) 的氯化物加成离子 [M + Cl]- 的 LC-MS/MS 分析性能特征。计算基于 THF/水溶剂系统，其中以 2% 的组成添加二氯甲烷作为添加剂，以在溶液的电喷雾电离 (ESI) 期间生成氯 (Cl-) 离子。与传统上用于测定两种分析物的去质子化 [MH]- 离子相比，使用 [M + Cl]- 加合离子作为母离子时的选择性和信噪比 (S/N) 非常出色。TAP 和 FFC 的总离子色谱图 (TIC) 中的 S/N 比分别为 577 和 3062，而在 50 和 100 μg/kg 的相同加标水平下使用 [M−H]− 时，S/N 比分别为 167 和 452 . 使用 [M + Cl]- 时，TAP 和 FFC 的检测限 (LOD) 分别为 4.0 和 3.7 μg/kg，而使用 [M-H]- 时分别为 2.1 和 4.3 μg/kg。[M + Cl]- 加合离子被证明是 [M-H]- 的极好替代品，尤其是在两种分析物定量之前，身份和选择性将成为分析方法的关键驱动因素的情况下。