A liquid chromatography tandem mass spectrometric method was developed for the determination of two β-agonists (ractopamine and salbutamol) in pig hair samples. An isotope of ractopamine-d5 or salbutamol-d6 as an internal standard was used to carry out quantitative analysis. Concentrated sodium hydroxide was used to pretreat hair samples and then purified by the solid phase extraction (SPE) procedure. The extracted solution was evaporated and reconstituted for injection in the instrument with electrospray ionization (ESI) operating in a positive multiple-reaction-monitoring (MRM) mode. Ractopamine and salbutamol separation were performed on C18 analytical column under gradient condition. The internal standard calibration curve was linear in the range of concentration from 0.5 to 100 ng mL-1 (R2 > 0.995). Recoveries of this method estimated at three spiked concentrations of 100, 250 and 500 ng mL-1 in pig hair samples, were 79-82% for ractopamine and 77-96% for salbutamol. The corresponding inter-day and intra-day precisions expressed as relative standard deviation (RSD %) were 3.8-6.4% and 3.8-8.6%, respectively. The analytical time for one sample was 8 min. The detection limit of this method was 0.6 and 8.3 ng mL-1 for ractopamine and salbutamol, respectively. This developed method can be applied for monitoring the use of the β-agonists salbutamol and ractopamine in swine feed incurred pig hair.

中文翻译：

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液相色谱串联质谱法测定猪毛中莱克多巴胺和沙丁胺醇

建立了一种液相色谱串联质谱法，用于测定猪毛样品中的两种 β-受体激动剂（莱克多巴胺和沙丁胺醇）。使用莱克多巴胺-d5或沙丁胺醇-d6的同位素作为内标进行定量分析。浓氢氧化钠用于预处理头发样品，然后通过固相萃取 (SPE) 程序进行纯化。将提取的溶液蒸发并重新配制用于在仪器中进行注射，电喷雾电离 (ESI) 以正向多反应监测 (MRM) 模式运行。莱克多巴胺和沙丁胺醇在梯度条件下在 C18 分析柱上进行分离。内标校准曲线在 0.5 至 100 ng mL-1 的浓度范围内呈线性（R2 > 0.995）。该方法在猪毛样品中的三种加标浓度分别为 100、250 和 500 ng mL-1 时，莱克多巴胺和沙丁胺醇的回收率分别为 79-82% 和 77-96%。以相对标准偏差 (RSD %) 表示的相应日间和日内精度分别为 3.8-6.4% 和 3.8-8.6%。一个样品的分析时间为 8 分钟。该方法对莱克多巴胺和沙丁胺醇的检测限分别为 0.6 和 8.3 ng mL-1。这种开发的方法可用于监测猪饲料中产生的猪毛中β-激动剂沙丁胺醇和莱克多巴胺的使用。分别为 6%。一个样品的分析时间为 8 分钟。该方法对莱克多巴胺和沙丁胺醇的检测限分别为 0.6 和 8.3 ng mL-1。这种开发的方法可用于监测猪饲料中产生的猪毛中β-激动剂沙丁胺醇和莱克多巴胺的使用。分别为 6%。一个样品的分析时间为 8 分钟。该方法对莱克多巴胺和沙丁胺醇的检测限分别为 0.6 和 8.3 ng mL-1。这种开发的方法可用于监测猪饲料中产生的猪毛中β-激动剂沙丁胺醇和莱克多巴胺的使用。