Solvent bar microextraction combined with HPLC-DAD for simultaneous determination of diuretics in human urine and plasma samples

Background: A simple and powerful microextraction procedure, the solvent bar microextraction (SBME), was used for the simultaneous determination of two diuretics, furosemide and spironolactone in human urine and plasma samples, using high-performance liquid chromatography coupled with diode array detection (HPLC-DAD). Methods: The appropriate amount (2 µL) of 1-octanol as an organic solvent confined within (2.5 cm) of a porous hollow fiber micro-tube, sealed at both ends was used for this procedure. The conditions for the SBME were optimized in water and the analytical performance were examined in spiked human urine and plasma samples. Results: The optimized method exhibited good linearity (R2 > 0.997) over the studied range of higher than 33 to 104 µg L-1 for furosemide and spironolactone in urine and plasma samples, illustrating a satisfactory precision level with RSD values between 2.1% and 9.1%. Discussion: The values of the limits of detection were found to be in the range of 6.39 to 9.67 µg L-1, and extraction recovery˃ 58.8% for both diuretics in urine and plasma samples. The applicability and effectiveness of the proposed method for the determination of furosemide and spironolactone in patient urine samples were tested. Conclusion: In comparison with reference methods, the attained results demonstrated that SBME combined with HPLC-DAD was proved to be simple, inexpensive, and promising analytical technology for the simultaneous determination of furosemide and spironolactone in urine and plasma samples.

Trace Determination of Tamoxifen using Optimized Solvent Bar Microextraction and HPLC-UV

Background: Tamoxifen (Soltamox) is an antineoplastic agent and an estrogen receptor antagonist used to treat breast cancer, but have severe side effects such as hot flashes, vaginal discharge, etc. Dose monitoring is a necessity for optimum treatment, to prevent severe adverse effects. Methods: In this study, the solvent bar microextraction method (SBME) was used for preconcentration and microextraction coupled with High-performance liquid chromatography-ultraviolet (HPLC-UV) analysis of tamoxifen. Results: The limit of detection and limit of quantification were 13.3 and 40 μgL-1, respectively. The linear range was between 40 and 10000 μgL-1 with a correlation coefficient of 0.999. The enrichment factor was 169 and the relative standard deviation within-day and between-day were 3.6 and 4.0, respectively. Conclusion: The use of sensitive SBME method coupled with HPLC-UV analysis for detection of tamoxifen at trace level proved to be successful, offering a desirable preconcentration factor, and a costeffective and green set-up for determining its rate of elimination from cancer patients and wastewater.

The application of three-phase solvent bar microextraction based on a deep eutectic solvent coupled with high-performance liquid chromatography for the determination of flavonoids from vegetable and fruit juice samples

In the present study, a new three-phase solvent bar microextraction based on a deep eutectic solvent (SBME-DES) was developed for the preconcentration and extraction of quercetin (Qu) and morin (Mo) from vegetable and fruit juice samples.

Ephedrine Analysis in Real Urine Sample via Solvent Bar Microextraction Technique Coupled with HPLC-UV and Chemometrics

Background: Ephedrine, an alpha/beta-adrenergic agonist, is one of the most common doping agents not only among athletes but also the ordinary people, therefore its detection at low trace levels with a sensitive and cost effective method has become a priority to investigate many analytical methods. Objective: In this work, solvent bar microextraction followed by high-performance liquid chromatography (HPLC-UV) was used for extraction and determination of ephedrine at low trace levels from urine samples at optimum condition. Methods: In this study, a designed experiment was carried out using solvent bar microextraction technique, which has been proved to be a green method. This method requires three phases consisting of a donor phase with an alkaline pH, an acceptor phase with an acidic pH, and organic solvent to impregnate the pores of the hollow fiber. The obtained results were used for estimating the optimum ranges for each parameter, analyzing the effect of different parameters, simultaneously. Results: Under optimized circumstances, the preconcentration factor was 129. The calibration curves represented good linearity for urine sample with coefficient estimations higher than 0.9991. The limit of detection and quantitation for ephedrine were 16.7 µg L-1 and 50 µg L-1, respectively. The relative standard deviations of analysis were 3.5% within a day (n=3) and 4.1% between days (n=9). Conclusion: According to the results and previous studies, it can be concluded that the preconcentration factor for ephedrine was the best result ever reported considering selectivity and cost-effectiveness.

Carrier-mediated solvent bar microextraction coupled with HPLC-DAD for the quantitative analysis of the hydrophilic antihypertensive peptide VLPVPR in human plasma

Aliquat-336, an anion carrier, facilitates the extraction of hydrophilic VLPVPR peptide by Solvent-Bar-Micro-Extraction, achieving sensitive peptide analysis in biological samples.