Application of capillary zone electrophoresis with large‐volume sample stacking to the sensitive determination of sulfonamides in meat and ground water

Abstract

A CZE method with UV-Vis detection has been established and validated for the determination of nine sulfonamides: sulfapyridine, sulfamethazine, sulfamerazine, sulfamether, sulfadiazine, sulfadimethoxine, sulfamethoxazole, sulfachlorpyridazine, and sulfamethizole. Optimum separation was obtained on a 64.5 cm x 75 microm bubble cell capillary using a buffer containing 45 mM sodium phosphate and 10% methanol at pH 7.3, with temperature and voltage of 27 degrees C and 25 kV, respectively. p-Aminobenzoic acid was used as an internal standard . Taking into account the lack of sensitivity of the UV-Vis detection, the application of an on-line preconcentration methodology, such as large-volume sample stacking with polarity switching has been proposed. This procedure combined with a solvent extraction/SPE method applied for off-line preconcentration and cleanup provides a significant improvement in the LODs, ranging from 2.59 to 22.95 mug/L for the studied compounds; the quantification of these residues being possible below the levels established by EU legislation in animal food products, such as meat. Satisfactory recoveries were also obtained in the analysis of these compounds in ground water.

Simultaneous determination of different classes of antibiotics in fish and livestock by CE‐MS

“…The optimum buffer pH for the separation would be in the range of 5-6 [21,22]. However, Soto-Chinchilla et al [26] separated nine sulfonamides, including the four determined in the present study, using a buffer containing 45 mM sodium phosphate and 10% of methanol at pH 7.3. To find the best running buffer suitable for the separation of the analytes they checked different buffers in a pH range of 2-10.…”

Determination of additives and organic contaminants in food by CE and CEC

“…The LODs were reported to be less than 10 mg/kg for the antibiotics studied. Soto-Chinchilla et al [84] investigated the determination of nine sulphonamides (several common to the previous reports) in meat using CZE and UV-Vis detection. In this instance, both online preconcentration (LVSS) and offline preconcentration/cleanup (liquid-liquid extraction and SPE) was investigated as a means of improving sensitivity.…”

Analytical methods for multiresidue determination of sulfonamides and trimethoprim in meat and ground water samples by CE‐MS and CE‐MS/MS

“…Also, in order to consider the compatibility of a CE method with MS, a volatile buffer of low conductivity (i.e., electric current below 50 mA) must be used to avoid plugging of the dielectric capillary between the spray chamber and the mass spectrometer, as well as to obtain a stable electrospray. Satisfactory separations for sulfonamides can be achieved with alkaline buffers [43]; for this reason, only ammonium acetate and ammonium carbonate buffers were tested, selecting the former, as it provided better resolutions. As a summary, the studied ranges and selected values of all the parameters concerning the electrophoretic separation are shown in Table 2.…”

“…Different aliquot of 40 mL of filtered water sample were spiked with different concentrations of sulfonamides and TMP, following a treatment previously reported [43]. The final residue was reconstituted with 500 mL of 1 N NH 3 solution containing 1 mg/mL LOM as IS.…”

“…Different portions of 4g of meat were accurately weighed and spiked with different concentration levels of sulfonamides and TMP. For extraction and preconcentration, a sample treatment with some modifications from other previously reported method [43] was used, based on the use of ACN for extraction and Oasis HLB SPE cartridges for cleanup and preconcentration. The final extract was reconstituted in 500 mL of 1 N NH 3 solution in water containing 1 mg/mL LOM as internal standard (IS).…”