Use of SDS micelles for improving sensitivity, resolution, and speed in the analysis of β‐lactam antibiotics in environmental waters by SPE and CE

Abstract

This study dealt with the potential of MEKC with LIF detection involving derivatization with sulfoindocyanine succinimidyl ester (Cy5) for the separation and determination of beta-lactam antibiotics (ampicillin, amoxicillin, cephradine, and cephalexin) in environmental water samples. Water samples of 50 mL were enriched by SPE by passage through a weak base-cation Amberlite(R) IRA-93 exchange column. SDS micelles play important roles in the whole analytical process by improving the yield (sensitivity) and the kinetics of the labeling reaction, the elution of the retained antibiotics from the SPE preconcentration system and the electrophoretic resolution of their Cy5-derivatives. The optimum procedure includes a derivatization step of the antibiotics at 25 degrees C for 10 min and direct injection for MEKC analysis, which is conducted within about 15 min using 15 mM SDS in the running buffer (35 mM sodium borate at pH 9.3). LODs from 30 to 45 ng/L and RSDs (within-day precision) from 3.5 to 5.9% were obtained for the antibiotics in water samples with average recoveries ranging from 96.4 to 99.4%. These results indicate that the method proposed is a straightforward and sensitive tool for the determination of these antibiotics in environmental water samples providing similar quantitative results to those using more expensive equipment like LC-electrospray MS/MS.

Determination of pharmaceuticals classified as emerging pollutants using capillary electrophoresis with capacitively coupled contactless conductivity detection

“…In this study, the emerging pollutants such as antiinflammatory and analgesic drugs (ibuprofen, diclofenac, naproxen, indomethacine and oxaprozin), antibiotics (cephalexin and penicillin G), beta-blockers (atenolol and metoprolol), lipid regulators (gemfibrozil and clofibric acid), an anticonvulsant (sodium valproate) and an antihistamine (diphenhydramine), were chosen as a representative target group of analytes [9,[16][17][18][19][20][21][22][23][24] (http://sofia.usgs.gov/projects/ scopesofwork03/epocs.html, http://www.epa.gov/nerlesd1/ bios/daughton/book-summary.htm, http://toxics.usgs.gov/ highlights/pharm_soils/listing.html). Structures and the pK a values of these analytes are given in Table 1.…”

“…(1) Atenolol, (2) metoprolol, (3) diphenhydramine, (4) cephalexin, (5) oxaprozin, (6) penicillin G, (7) indomethacine, (8) gemfibrozil, (9) ibuprofen, (10) diclofenac, (11) naproxen, (12) clofibric acid, (13) Subsequently, the optimum composition of n-PA in BGE was investigated. Different concentrations of n-PA ranging from 2.5 to 15% were studied.…”

“…These effects might include endocrine disrupting activities and the strengthening of the bacterial resistance exposed to subtherapeutic concentrations of antibiotics [4][5][6]. Hence, highly sensitive and accurate analysis technique, such as capillary electrophoresis (CE) is essential to monitor the presence and the concentrations of pharmaceutical compounds in the environment [7][8][9][10].…”

Fast investigations from biological matrices using CE – Test of a blood–brain barrier model

“…While CZE is particularly suitable for highly polar and charged compounds [15], MEKC is often the method of choice for uncharged analytes [18], In cases when CZE does not provide the desired results, e.g. for selectivity shortcomings, MEKC is often a suitable alternative [19,20]. As the surfactant breaks the drug-protein complexes while denaturising the proteins [21], the total amount of drug can be determined [18].…”

Separation of flavonoids and phenolic acids in complex natural products by microemulsion electrokinetic chromatography using surfactant‐coated and carboxylic single‐wall carbon nanotubes as additives

“…CE has attracted considerable attention on account of their different modes of separations that can be employed to address a broad range of applications under the influence of an electric field 9, 10. To improve the efficiency of separation, a variety of approaches for optimizing resolution in CE have been pursued vigorously by research groups in recent times, including the use of additives 11, 12, the modification of pseudostationary phase (PSP) 13, 14 and using coated capillaries 15. More recently, a novel analytical technique based on CNTs has been increasingly developed to enlarge the versatility of CE system and boost the performance of electrokinetic separation by altering solute partition coefficients 16, 17.…”