Chemometric Optimization of Cation-Selective Exhaustive Injection Sweeping Micellar Electrokinetic Chromatography for Quantification of Ractopamine in Porcine Meat

Abstract

An online stacking capillary electrophoresis (CE) method, cation-selective exhaustive injection sweeping micellar electrokinetic chromatography (CSEI-sweep-MEKC), is developed and optimized for analysis of ractopamine (RP) and its homologue dehydroxyractopamine (DRP) in porcine meat. Chemometric experimental design was used to achieve the best possible optimization and reduce the number of trials and errors. The CSEI-sweep-MEKC method enables nanogram per gram level analysis, with limits of detection (LODs) in meat of 5 ng/g for RP and 3 ng/g for DRP (S/N = 3). A higher conductivity buffer (HCB) zone was injected into the capillary, allowing for the analytes to be electrokinetically injected at a voltage of 9 kV for 12 min. Using 125 mM sodium dodecyl sulfate and 15% methanol in the sweeping buffer, RP and DRP were well-separated. The method was validated with a linear calibration curve of 10-300 ng/g (r > 0.994). In comparison to the normal capillary zone electrophoresis method (1 psi for 10 s), this stacking strategy resulted in 900 times sensitivity enhancement. This technique was further applied for analyzing seven kinds of commercial meats, and the residual RP was detected in one (5.76 ng/g of RP). The data were corresponding to the data analyzed by the commercial testing kit and mass spectrometry spectra. This method was successfully used on real samples and is considered feasible for serving as a tool for routine examination in markets.

Advances in the Analysis of Veterinary Drug Residues in Food Matrices by Capillary Electrophoresis Techniques

“…The method was an on-line stacking method, including exhaustive CSEI and sweeping with a 900 fold higher sensitivity (ng/g level) in comparison to CZE-UV. The capillary was filled with a long plug of a higher conductivity buffer and an electrokinetic injection of the sample was then performed; at the end, the compounds were separated by a sweeping buffer with SDS, whose electrostatic forces contributed to the mobility and resolution of the two analytes [104]. Similarly, FASI-sweep-MEKC improved the MEKC sensitivity by 400-2000 times (ng/mL), allowing the analysis of eight β-agonists (R-albuterol hydrochloride, cimaterol, clenbuterolhydrochloride, colterol, TER, tulobuterol, ractopamine hydrochloride, and zilpaterol) in animal feed samples.…”

Recent advances in the application of capillary electromigration methods for food analysis and Foodomics

“…Matrix interferences are often the major problem encountered in most of the analytical solutions developed for the determination of RP in meat samples. The quantitative determination of RP and its homologue dehydroxyractopamine has been recently approached using cation‐selective exhaustive injection (CSEI) sweeping‐MEKC . Using CSEI‐sweeping‐MEKC, samples are dissolved in a low‐conductivity matrix and are electrokinetically injected in to a higher conductivity buffer zone for a long time.…”

Therapeutic deferoxamine and deferiprone monitoring in β‐thalassemia patients’ plasma by field‐amplified sample injection and sweeping in capillary electrophoresis

“…FASI‐sweeping CE is widely used for enhancing the sensitivity . In this study, several parameters were investigated to optimize the separation, including phosphate buffer (60–120 mM) and pH values (2.0–4.0), SDS concentration (0–200 mM), and TEA concentration (0–100 mM).…”