Determination of endo- and exogenous corticosteroids by cyclodextrin-modified micellar electrokinetic chromatography with the use of on-line preconcentration

Карцова, Л. А.; Стрельникова, Е. Г.

doi:10.1134/s1061934807080035

Cited by 5 publications

(12 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The concentration of 50 mM was recognized as the most effective. Moreover, the pH of the buffer is another crucial parameter, affecting the velocity of the EOF and the migration times of analytes . Our study confirmed that the BGE at pH 8.8 containing borax and boric acid at concentrations of 5 mM and 150 mM, respectively, proved to be the best compromise between a good resolution and analysis time.…”

Section: Resultssupporting

confidence: 76%

“…For all hormones, the LOD was 15 ng/mL with a S/N of 3, whereas the LOQ, expressed as the lowest concentration in the calibration plot that can be detected with the precision expressed by RSD% below 15%, with accuracy expressed as a percentage of the nominal concentration within 80–120%, and a S/N better than 10, was 50 ng/mL (Supporting Information Table 1). The obtained results indicated that the elaborated method was sensitive, with LOQ values comparable or lower than for the earlier published MEKC methods .…”

Section: Resultsmentioning

confidence: 59%

“…On the other hand, the determination of steroid hormones is very analytically challenging because of the similarity in the physicochemical properties, the need for the hydrolysis of conjugated forms in urine, and the low levels in this body fluid. In recent years, studies enabling an assessment of steroid levels in urine samples were carried out by LC‐MS , GC‐MS , and CE with spectrophotometric detection (CE‐UV) or MS (CE‐MS) .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evaluation of various approaches to the isolation of steroid hormones from urine samples prior to FASS‐MEKC analysis

et al. 2017

View full text Add to dashboard Cite

The goal of this study was to assess various analytical approaches for the simultaneous and efficient extraction of steroid hormones (cortisone, cortisol, prednisolone, corticosterone, testosterone, 17α-methyltestosterone, epitestosterone, progesterone) from urine samples prior to separation based on field-amplified sample stacking MEKC (FASS-MEKC). FASS-MEKC successfully allowed the compounds to be separated within 12 min using a BGE composed of 5 mM sodium tetraborate, 150 mM boric acid, 50 mM SDS, and 15% methanol. Therefore, many procedures such as solid-phase microextraction, SPE, and dispersive liquid-liquid microextraction (DLLME) were tested and compared using a multivariate tool, namely, cluster analysis. Finally, DLLME-FASS-MEKC was validated and proved a good linearity of calibration curves (R above 0.9948) in a concentration range from 50 to 1000 ng/mL for all analytes. The LOD was established at 15 ng/mL, whereas the LOQ was 50 ng/mL. The intra- and interday precision, expressed as RSD%, did not exceed 9.97%. The DLLME-FASS-MEKC method was successfully applied to the analysis of urine samples from healthy volunteers and sportsmen. This methodology could prove to be useful in clinical studies and/or doping control depending on the steroid concentrations required in biomedical applications.

show abstract

Section: Resultssupporting

confidence: 76%

Section: Resultsmentioning

confidence: 59%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Evaluation of various approaches to the isolation of steroid hormones from urine samples prior to FASS‐MEKC analysis

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The appropriate choice of the type of buffer, the ionic strength (concentration), and the pH value can have a major impact on the quality and efficiency of electrophoretic separations. For the determination of steroid hormones alkaline buffers containing borax [1,25], ammonium acetate [21], sodium cholate [16] and containing small amounts of methanol (up to 20%) in each buffer have been mostly used. Kartsova et al [25] conducted a comparative study on the impact of the pH of the running buffer on the separation of steroid hormones by MEKC.…”

Section: Resultsmentioning

confidence: 99%

“…For the determination of steroid hormones alkaline buffers containing borax [1,25], ammonium acetate [21], sodium cholate [16] and containing small amounts of methanol (up to 20%) in each buffer have been mostly used. Kartsova et al [25] conducted a comparative study on the impact of the pH of the running buffer on the separation of steroid hormones by MEKC. The application of the reversed polarity of the electrodes and acidic buffer (pH = 2.5) allows for the separation of nine analytes while the use of the normal polarity and alkaline buffer (pH = 9.2) enabled the separation of only seven steroid hormones.…”

Section: Resultsmentioning

confidence: 99%

Optimization of a Pre-MEKC Separation SPE Procedure for Steroid Molecules in Human Urine Samples

et al. 2013

View full text Add to dashboard Cite

Many steroid hormones can be considered as potential biomarkers and their determination in body fluids can create opportunities for the rapid diagnosis of many diseases and disorders of the human body. Most existing methods for the determination of steroids are usually time-and labor-consuming and quite costly. Therefore, the aim of analytical laboratories is to develop a new, relatively low-cost and rapid implementation methodology for their determination in biological samples. Due to the fact that there is little literature data on concentrations of steroid hormones in urine samples, we have made attempts at the electrophoretic determination of these compounds. For this purpose, an extraction procedure for the optimized separation and simultaneous determination of seven steroid hormones in urine samples has been investigated. The isolation of analytes from biological samples was performed by liquid-liquid extraction (LLE) with dichloromethane and compared to solid phase extraction (SPE) with C 18 and hydrophilic-lipophilic balance (HLB) columns. To separate all the analytes a micellar electrokinetic capillary chromatography (MECK) technique was employed. For full separation of all the analytes a running buffer (pH 9.2), composed of 10 mM sodium tetraborate decahydrate (borax), 50 mM sodium dodecyl sulfate (SDS), and 10% methanol was selected. The methodology developed in this work for the determination of steroid hormones meets all the requirements of analytical methods. The applicability of the method has been confirmed for the analysis of urine samples collected from volunteers-both men and women (students, amateur bodybuilders, using and not applying steroid doping). The data obtained during this work can be successfully used for further research on the determination of steroid hormones in urine samples.

show abstract

Micellar electrokinetic chromatography: Methodological and instrumental advances focused on practical aspects

Silva

2009

Electrophoresis

View full text Add to dashboard Cite

This article reviews the latest methodological and instrumental improvements for enhancing sensitivity and resolution in MEKC-based determinations. On-line sample concentration (stacking, sweeping and combination of two protocols) and other on-capillary approaches such as in-capillary derivatization and the coupling of flow-injection systems with MEKC are the most relevant methodological approaches discussed for improving sensitivity. At the same time, changes in the BGE through the use of organic modifiers, ionic liquids, cations, CDs, non-ionic and zwitterionic surfactants, mixed micelles, vesicles and carbon nanostructures as well as 2-D CE and chemometric techniques for enhancing resolution are also considered in detail. Two instrumental approaches such as MS and LIF are also discussed, covering the proposals for overcoming the difficulties arising from the direct coupling of MEKC with MS and the excellent detection sensitivity achieved by LIF using the typical argon-ion laser and recent growth in the use of diode lasers as excitation sources. Some thoughts on potential future directions are also expressed.

show abstract

Determination of endo- and exogenous corticosteroids by cyclodextrin-modified micellar electrokinetic chromatography with the use of on-line preconcentration

Cited by 5 publications

References 11 publications

Evaluation of various approaches to the isolation of steroid hormones from urine samples prior to FASS‐MEKC analysis

Evaluation of various approaches to the isolation of steroid hormones from urine samples prior to FASS‐MEKC analysis

Optimization of a Pre-MEKC Separation SPE Procedure for Steroid Molecules in Human Urine Samples

Micellar electrokinetic chromatography: Methodological and instrumental advances focused on practical aspects

Contact Info

Product

Resources

About