Preparation of a teicoplanin-bonded chiral stationary phase for simultaneous determination of clenbuterol and salbutamol enantiomers in meat by LC-MS/MS

Abstract

We reported a new preparation method of teicoplanin-bonded chiral stationary phase(TCSP) by the “thiol-ene” addition reaction for the first time. Teicoplanin was first methacrylated, and then the methacryl and mercaptopropyl silica gel were subjected to the “thiol-ene” addition reaction to prepare TCSP. The high resolution (Rs) 2.72 for clenbuterol (CLEN) and 1.91 for salbutamol (SAL) enantiomers on homemade TCSP were simultaneously achieved by a optimal polar organic mobile phase (methanol/acetonitrile/ammonium formate/acetic acid, 480/120/0.3/0.04, v/v/m/v), with a flow rate of 0.5 mL min−1 at 35°C within 20 min. After the solid-phase extraction, a fast and sensitive LC-MS/MS method for the enantiomeric quantitation of the β2-agonists CLEN and SAL in 200 meat sampleswas established by multiple reaction monitoring (MRM) of positive ion. The precision, accuracy, stability, linearity and limits of detection (LODs) of the method were investigated, separately. This new method has good linear relationship for all enantimers over ranges of 0.5-50 μg L−1 (r≥0.995), high recoveries (87-103% for CLEN, 93-103% for SAL) and high reproducibilities (RSDs, 2.65-7.98% for intra-day, 4.23-9.29% for inter-day). The enantiomeric LODs were below 0.018 for CLEN and 0.076 μg kg−1 for SAL. The results showed that all positive samples contained unequal enantiomers, especially the R/S isomerization ratio in pork liver was as high as 1.3, which revealed that the β2-agonists were enantioselectively metabolized in animal bodies. It is important to scientifically evaluate the toxicity of β2-agonists to humans. The preparation of TCSP by thiol-ene addition was not only simple and convenient, but also could greatly reduce analytical cost.