Field-amplified on-line sample stacking for separation and determination of cimaterol, clenbuterol and salbutamol using capillary electrophoresis

Tong

et al. 2008

Self Cite

A simple, rapid, sensitive and specific method using capillary electrophoresis (CE) coupled with electrostacking and amperometric detection (AD) has been developed for the simultaneous separation and determination of clenbuterol (CLB), terbutaline (TER), salbutamol (SAL) and formoterol (FMT). In this paper, the CE separation and AD conditions were investigated in detail. The optimum conditions were: pH 8.6 Na(2)B(4)O(7)-H(3)BO(3) buffer solution (20.0 mmol/L), 9 kV for the separation voltage, and 1000 mV (versus Ag/AgCl) for the detection potential. When the sample which was dissolved in 70% ACN-water mixture solution was injected 60 s by 15 kV electrokinetic injection, the best stacking effects was obtained. Under the optimum conditions, the enhancement factors of these beta(2)-agonists had been greatly improved more than 5500-fold compared with the conventional electrokinetic injection. And then an excellent linear response was obtained with LODs (S/N = 3) of 0.098, 0.024, 0.063 and 0.920 pmol/L for CLB, TER, SAL and FMT in urine, respectively. The precision was determined in both intra-day (n = 5) and inter-day (n = 15) assays, and the RSDs were not more than 2.1 and 3.4% for migration time and peak current, respectively. The proposed method has been applied to analyze human urine samples successfully.

mentioning

confidence: 96%

Electrostacking online sample pre‐concentration capillary electrophoresis with amperometric detection for β₂‐agonists in human urine

Tong

et al. 2008

Self Cite

“…The presence of aprotic solvent such as acetonitrile in the background electrolyte enhances the solubility of most basic drugs by increasing their actual pK a values [39 -41], thus raising the pK a difference between such analytes and improving their separation selectivity in aqueousorganic and non-aqueous CZE [26]. Similarly, as implied by pertinent examples [42,43], electrokinetic injection with sample stacking was performed to improve the concentration sensitivity during detection of drugs in the CE system applied here by employing resistance (or conductivity) difference between the sample solvent and the used background solution. In addition, the low acidic background electrolyte significantly decreased the interactions of residual silanol groups on the walls of the fused-silica capillary with the fully protonated drugs [35,41].…”

Section: Migration Of Solutes In Ce Systemmentioning

confidence: 97%

“…In addition, the low acidic background electrolyte significantly decreased the interactions of residual silanol groups on the walls of the fused-silica capillary with the fully protonated drugs [35,41]. The acidic running electrolyte solution with low pH (2.0 -3.5) was frequently applied in non-chiral [36, 42 -44] and enantioselective [38] separation of catecholamines, beta-blockers, and beta-agonists with CE systems employing uncoated [36,42,43], coated [44,45], C18 covalently bonded [46] fused-silica capillaries or using titanium dioxide nanoparticles as additive in BGE [36]. Symbols: tm -migration time (mean l SD; n = 5); Rs -resolution of two subsequent analytes; lact -apparent solute mobility; leff -effective solute mobility; D -diffusion coefficient; pKa -first acidic ionisation constant; log P -n-octanol -water partition coefficient; MW -molecular weight; HBA -number of hydrogen bond acceptors in analyte molecule.…”

Section: Migration Of Solutes In Ce Systemmentioning

confidence: 99%

Hydrophobicity‐aided potentiometric detection of catecholamines, beta‐agonists, and beta‐blockers in a mixed‐solvent capillary electrophoresis system

Bazylak¹,

Monge

Everaert

et al. 2008

A series of cationic drug-like substances with distinct basicity, hydrogen-bonding ability, and hydrophobicity, including three catecholamines, two beta-agonists, and thirteen beta-blockers, was successfully detected in a capillary electrophoresis system using an end-capillary coupled potentiometric sensor consisting of a PVC-based liquid membrane deposited directly on a 100 mum diameter copper rod. The electrophoretic separation was performed on a 72 cm x 75 microm id uncoated fused-silica capillary with an acidic background electrolyte containing phosphoric acid in a water-acetonitrile mixture, pH* 2.8. Samples were injected electrokinetically at 5.0 kV for 10 s and a running voltage of 19.5 kV was applied. Excluding the bufuralol/practolol pair, baseline separation of all substances was achieved in the developed CE system within 9 minutes. A linear relationship (R(2) 0.8752) between the sensitivity of the applied potentiometric detector and the parameter log P characterising the hydrophobicity of the analytes was demonstrated. The best observable limits of detection (LODs) were obtained for the highly hydrophobic substances, i. e. bufuralol (8.10 x 10(-8) M injected concentration, S/N = 3), propranolol, alprenolol, and clenbuterol (ca. 1.10 x 10(-7) M). In the case of hydrophilic catecholamines and carbuterol their LODs with potentiometric detection were lowered by a factor of almost one thousand, reaching a value of 6.6 x 10(-5) M.

“…At present, several analytical methods have been reported for the determination of CLB in urine, including GC [4 -6], HPLC [6 -10], CE [11,12], and ELISA [7]. In addition, the complexity of urine samples requires an effective and efficient sample preparation technique for drug analysis.…”

Section: Introductionmentioning

confidence: 99%

Extraction of clenbuterol from urine using hydroxylated poly(glycidyl methacrylate‐co‐ethylene dimethacrylate) monolith microextraction followed by high‐performance liquid chromatography determination

Wang¹,

Feng²

2007

A hydroxylated poly(glycidyl methacrylate-co-ethylene dimethacrylate) (GMA-co-EDMA) monolithic capillary was prepared for polymer monolith microextraction (PMME). Coupled to HPLC with UV detection, this extraction medium was successfully applied to establish a simple and fast method for the analysis of clenbuterol (CLB) in urine. To obtain optimum extraction performance, the effects of pH value and ionic strength of the sample matrix on extraction efficiency were investigated. The linearity of the method was evaluated over a concentration range of 10-2000 ng/mL and the correlation coefficient (R2 value) was 0.9985. The detection limit and quantification limit were 2.3 and 7.7 ng/mL, respectively. Good reproducibility of the method was obtained, yielding the intra- and interday RSDs less than 5.1 and 9.1%, respectively. Moreover, the hydroxylated poly(GMA-co-EDMA) monolithic capillary exhibited good preparation reproducibility and long-term extraction life. When applied to the determination of CLB in urine samples, an effective removal of interfering compounds was achieved and recoveries were in the range of 87.6-106%. The determination of CLB from one real sample including pretreatment, extraction, and analysis could be finished within 30 min.