On-line preconcentration and determination of ketamine and norketamine by micellar electrokinetic chromatography

Jen, Hsiu Ping; Tsai, Yuan Chien; Su, Hsiu Li; Hsieh, You‐Zung

doi:10.1016/j.chroma.2005.05.019

Cited by 39 publications

(8 citation statements)

References 19 publications

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“…At a longer HCB length, the cations stacked into a narrower zone, thereby enhancing the efficiency; nevertheless, in terms of the resolution of cocaine and norcocaine, an injection HCB length of 36.3 cm provided optimal improved sensitivity and separation efficiency. A few papers have suggested that inserting a plug of water after injecting the HCB zone can improve the sample stacking as a result of the different electric field strengths accelerating the cations into the capillary [23,25]. In our hands, however, this process did not have any obvious effect and, therefore, we did not inject water in our subsequent experiments.…”

Section: Optimizing the Hcb Injection Lengthmentioning

confidence: 79%

“…If sweeping-MEKC concentration is employed, the detection limit can be improved by ca. 10-1000-fold [22,23]; if, however, sweeping-MEKC is coupled with selective electrokinetic injection, the sensitivity can be further enhanced by up to 10 6 -fold [24]. Among the many on-line preconcentration methods available, one of the best preconcentration efficiencies is provided by the cation-selective exhaustive injection (CSEI)-sweeping-MEKC technique -used for the detection of cationic analytesperformed in conjunction with selective electrokinetic injection, followed by the addition of surfactants to perform the sweeping process.…”

Section: Introductionmentioning

confidence: 99%

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Determination of cocaine and its metabolites using cation‐selective exhaustive injection and sweeping‐MEKC

Feng

Jen

et al. 2008

Electrophoresis

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We have employed a high-sensitivity on-line preconcentration method, cation-selective exhaustive injection (CSEI) and sweeping MEKC, for the analysis of cocaine, benzoylecgonine, norcocaine, and cocaethylene. We monitored the effects of several of the CSEI-sweeping-MEKC parameters - including the pH, the concentrations of SDS and organic modifier, the injection length of the high-conductivity buffer, and the injection time of the sample - to optimize the separation process. The optimal BGE was 100 mM phosphoric acid (pH 1.8) containing 75 mM SDS with 10% 2-propanol and 10% tetrahydrofuran as the organic modifier. In addition, electrokinetic injection of the sample at 15 kV for 900 s provided both high separation efficiency and enhanced sweeping sensitivity. The sensitivity enhancements for cocaine, norcocaine, and cocaethylene ranged from 2.06 x 10(4) to 3.96 x 10(4); for benzoylecgonine it was 1.75 x 10(3); the coefficients of determination exceeded 0.9958. The LODs, based on an S/N ratio of 3:1, of sweeping-MEKC ranged from 33.5 to 52.8 ng/mL; in contrast, when using CSEI-sweeping-MEKC the sensitivity increased to range from 29.7 to 236 pg/mL. Under the optimal conditions, we analyzed cocaine in a human urine sample prepared using off-line SPE to minimize the influence of the matrix. The recovery of the SPE efficiency was satisfactory (ca. 74.9-87.6%). Our experimental results suggest that, under the optimal conditions, the CSEI-sweeping-MEKC method can be used to determine cocaine and its metabolites with high sensitivity in human urine.

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Section: Optimizing the Hcb Injection Lengthmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Determination of cocaine and its metabolites using cation‐selective exhaustive injection and sweeping‐MEKC

Feng

Jen

et al. 2008

Electrophoresis

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“…Jen et al . (2006) cites the high number of theoretical plates and low sample consumption as an advantage of CE separation; however, comparable sensitivity to GC‐MS when measuring KET and NOR from urine (5 µg/mL vs 10 ng/mL with GC‐MS) was not achieved.…”

Section: Discussionmentioning

confidence: 99%

Trends in bioanalytical methods for the determination and quantification of club drugs: 2000–2010

Brown

Melton

2010

Biomedical Chromatography

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The term 'club drug' can be loosely defined as any substance used to enhance social settings. Such drugs are commonly found at raves or similar all-night dance parties and include methamphetamine, 3,4-methylenedioxymethamphetamine, gamma-hydroxybutyrate (GHB), ketamine (KET), and flunitrazepam (FLU). These drugs have potentially dangerous side effects including hallucinations, paranoia, amnesia and hyperthermia. In addition, GHB, KET and FLU are considered predatory drugs due to their roles in drug-facilitated sexual assault. Forensic and regulatory agencies routinely have the need for determination and accurate quantification of these drugs in biological fluids, especially in cases of mortality or criminal investigations. This review presents the chromatographic and spectroscopic methods published for such analyses over the last decade, including sample preparation techniques and validation data.

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“…In this study, they comprehensively examined the influence of buffer composition on the electrophoretic pattern of the mixture of negatively charged C-dots by varying buffer type, pH, and concentration. Although CE is a powerful technique that is simple to perform and achieves satisfactory separation efficiency, the benefits provided by the high number of theoretical plates obtained with CE for C-dots separation are overshadowed by its low sensitivity of the UV detection systems owning to the small injection volumes of sample [185]. To overcome the limitation of the low sensitivity and ensure the accuracy for C-dots analysis, our research group separated C-dots by use of commercial CZE apparatus coupled with a diode array detector (1), (2), and (3) are positively charged, neutral, and negatively charged C-dots, respectively [94].…”

Section: Capillary Zonementioning

confidence: 99%

Characterization and Analytical Separation of Fluorescent Carbon Nanodots

Gong

Liu

et al. 2017

Journal of Nanomaterials

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Carbon nanodots (C-dots) are recently discovered fluorescent carbon nanoparticles with typical sizes of <10 nm. The C-dots have been reported to have excellent photophysical and chemical characteristics. In recent years, the advances in the development and improvement in C-dots synthesis, characterization, and applications are burgeoning. In this review, we introduce the most commonly used techniques for the characterization of C-dots. The characterization techniques for C-dots are briefly classified, described, and illustrated with applied examples. In addition, the analytical separation methods for C-dots (including electrophoresis, chromatography, density gradient centrifugation, differential centrifugation, solvent extraction, and dialysis) are included and discussed according to their analytical characteristics. The review concludes with an outlook towards the future developments in the characterization and the analytical separation of C-dots. The comprehensive overview of the characterization and the analytical separation techniques will safeguard people to use each technique more wisely.

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On-line preconcentration and determination of ketamine and norketamine by micellar electrokinetic chromatography

Cited by 39 publications

References 19 publications

Determination of cocaine and its metabolites using cation‐selective exhaustive injection and sweeping‐MEKC

Determination of cocaine and its metabolites using cation‐selective exhaustive injection and sweeping‐MEKC

Trends in bioanalytical methods for the determination and quantification of club drugs: 2000–2010

Characterization and Analytical Separation of Fluorescent Carbon Nanodots

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