按NY/T 468-2006所述方法在碱性条件下,用乙酸乙酯提取和用盐酸溶液反萃取制得含有盐酸克伦特罗的试样溶液,调节溶液的酸度至pH 4.5后,经SCX固相萃取柱净化。在经净化后的试液中加入1.6 mg·L-1美托洛尔溶液40 μL作为内标。将溶液置于60 ℃水浴中吹氮蒸干,加入甲苯200 μL和BSTFA衍生试剂100 μL,于80 ℃烘箱中衍生1 h。冷却后再加甲苯200 μL,经DB-5MS毛细管柱分离,在SIM模式下进行MS测定,选择监测离子为m/z 86(定量离子)和m/z 262,243,187(定性离子)。内标法定量。盐酸克伦特罗的线性范围为16~512 μg·L-1,其检出限(3S/N)为1.0 μg·kg-1。以空白样品为基体进行加标回收试验,测得回收率在79.7%~86.6%之间,测定值的相对标准偏差(n=6)在4.8%~6.7%之间。

Pork sample was extracted under alkaline condition with ethyl acetate and back-extracted with HCl solution as described in NY/T 468-2006. The solution obtained was adjusted to pH 4.5 and purified by passing through SCX SPE column. After adding 40 μL of 1.6 mg·L-1 metoprolol solution as internal standard, the sample solution was evaporated to dryness by N2-blowing in a water bath at 60 ℃, 200 μL of toluene and 100 μL of BSTFA were added to the residue, and derivatized for 1 h in an oven at 80 ℃. After cooling, 200 μL of toluene were added, and derivates in the solution were separated on DB-5MS capillary column. MS determination was performed under SIM mode and quantification was carried out by the internal standard method. The monitoring ions of m/z 86 (as quantitative ion) and of m/z 262, 243 and 187 (as qualitative ions) were selected in the analysis. Linearity range for clenbuterol was kept between 16 μg·L-1 and 512 μg·L-1, and detection limits (3S/N) found was 1.0 μg·kg-1. On the base of blank sample, test for recovery was made by standard addition method, giving values of recovery in the range of 79.7%-86.6%, with values of RSD′s (n=6) in the range of 4.8%-6.7%.