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Improved nonaqueous capillary electrophoresis for tetracyclines at subparts per billion level
Author(s) -
Ma TzuYi,
Vickroy Thomas W.,
Shien JuiHung,
Chou ChiChung
Publication year - 2012
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201100485
Subject(s) - chromatography , capillary electrophoresis , detection limit , chemistry , urine , analyte , oxytetracycline , extraction (chemistry) , sample preparation , antibiotics , biochemistry
A NACE method with laser‐induced fluorescence detection was modified for sensitive detection of 4 tetracyclines (TCs) in biological samples and feeds. The changes in injection mode, injection times, id of capillary, excitation wavelength, and the use of surfactant and sample stacking technique all contributed to improved LODs of TCs to sub‐ng/mL level. With the optimized conditions, the instrumental LODs could reach 1.33 ng/mL for chlorotetracycline (CTC) and 13.3 ng/mL for TC, oxytetracycline (OTC), and doxycycline (DC), an improvement of 10–100‐fold over past studies. A simple SPE procedure was further developed for the extraction and concentration of TCs in plasma, urine, feed, and milk. Taken together, the instrumental LOD and feasible SPE concentration factors the overall LODs for CTC could reach 65 pg/mL in feed and milk and 260 pg/mL in plasma and urine. Detection limits for TC, OTC, and DC at sub‐ng/mL level were also achieved. The modified CE‐LIF method was found to be less complicated and more sensitive than the best current methods using UV or LIF detection, and has been applied successfully to assess oral absorption of DC in swine and chickens and to confirm suspected TC‐positive bovine serum samples.