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

Magnetic molecularly imprinted polymers coupled with UPLC-MS/MS for simultaneous detection of 19 steroid hormones in human plasma

Steroid hormones constitute a group of hormones with molecular weights ranging from 200 to 400 daltons, characterized by their highly similar chemical structures. Each hormone within this group holds significant value for the diagnosis of various diseases. Accurate clinical measurement of the levels of each hormone is crucial for the diagnosis in clinical settings. Due to the wide variety and different properties of steroid hormones in organisms, sample pretreatment is the rate-limiting step for analysis and detection. In this paper, magnetic molecule-imprinting polymers (MMIPs) were prepared by surface imprinting on silicon coated magnetic spheres, and a detection method of MMIPs-combined with liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for 19 steroid hormones in plasma was developed and verified. Fourier transform infrared spectroscopy, field emission scanning electron microscopy and transmission electron microscopy were used to confirm the formation of MMIPs materials, and the conditions of material synthesis and pretreatment of steroid hormones from plasma were optimized. The detection method was evaluated by using linearity, LOD and LOQ, precision, accuracy and matrix effect. The linearity of 19 steroid hormones was good, and the linear correlation coefficient was greater than 0.995. The coefficients of variation were 2.1-9.8 % and 1.1-9.7 % for intra-day and inter-day, respectively, and the recoveries were 83.6 %-118.2 % at low concentration, and the recoveries of medium and high concentrations were 94.6 %-113.8 % and 89.5 %-113.6 %, respectively. The coefficient of variation of Relative matrix effect of 19 steroid hormones measured in different batches of plasma was 2.1-5.4 % after isotope internal standard correction, which eliminated the influence of matrix effect.

A simple and green offline-online capillary electrophoresis stacking strategy for the simultaneous determination of hydrophobic compounds in complicated samples using sodium dodecyl sulfate as the solubilizer and pseudophase

BACKGROUND

Capillary electrophoresis is a powerful analytical method featured with high separation efficiency, minimal sample requirements, and reduced organic solvents consumption. However, its low sensitivity hinders its wide application in determination of trace analytes especially for the weakly ionized hydrophobic compounds. Offline and Online capillary electrophoresis stacking methods are more favored to enhance detection sensitivity of analytes. The determination of two sesquiterpenes and an alkaloid from the dried root of Lindera aggregata merged as an example for developing a simple, sensitive and green method for the simultaneous determination of two hydrophobic compounds in complicated matrix samples.

RESULTS

An offline-online capillary electrophoresis stacking strategy by integrating micro matrix solid phase dispersion with field-amplified sample stacking and micelle to cyclodextrin stacking has been developed for the simultaneous determination of dehydrocostus lactone, linderane, norisoboldine in complex matrices. The optimized parameters were set at 65 mM sodium dihydrogen phosphate, 35 % methanol, 180 s for sample injection and 210 s for cyclodextrin injection, 20 mM sodium dodecyl sulfate of sample matrix for online stacking; 1:1 sample to MCM-48, 180 s grinding time, and 1000 μL of 20 mM sodium dodecyl sulfate elution for offline procedure. Under the optimum conditions, the method showed good linearity with correlation coefficients (R2 ≥ 0.9927), low limits of detection within the range of 25-50 ng mL-1, satisfactory repeatability and reproducibility below 3.98 %, and acceptable recoveries between 94 % and 97 %. The developed method was successfully applied to two real samples, the root of L. aggregata and rat feces.

SIGNIFICANCE

Sodium dodecyl sulfate is firstly used as an eluent in micro matrix solid phase dispersion and plays a dual role throughout the analytical procedure, including extraction solvent in sample preparation and micelle pseudophase during online stacking. It brings great procedure convenience to the method. The sensitivity of this method can improve up to 1283-folds compared with the normal mode. Moreover, the overall strategy indicates satisfied green potential evaluated by greenness assessment tools.

A Non-Instrumental Green Analytical Method Based on Surfactant-Assisted Dispersive Liquid-Liquid Microextraction-Thin-Layer Chromatography-Smartphone-Based Digital Image Colorimetry(SA-DLLME-TLC-SDIC) for Determining Favipiravir in Biological Samples

Favipiravir (FAV) has become a promising antiviral agent for the treatment of COVID-19. Herein, a green, fast, high-sample-throughput, non-instrumental, and affordable analytical method is proposed based on surfactant-assisted dispersive liquid-liquid microextraction (SA-DLLME) combined with thin-layer chromatography-digital image colourimetry (TLC-DIC) for determining favipiravir in biological and pharmaceutical samples. Triton X-100 and dichloromethane (DCM) were used as the disperser and extraction solvents, respectively. The extract obtained after DLLME procedure was spotted on a TLC plate and allowed to develop with a mobile phase of chloroform:methanol (8:2, v/v). The developed plate was photographed using a smartphone under UV irradiation at 254 nm. The quantification of FAV was performed by analysing the digital images' spots with open-source ImageJ software. Multivariate optimisation using Plackett-Burman design (PBD) and central composite design (CCD) was performed for the screening and optimisation of significant factors. Under the optimised conditions, the method was found to be linear, ranging from 5 to 100 µg/spot, with a correlation coefficient (R2) ranging from 0.991 to 0.994. The limit of detection (LOD) and limit of quantification (LOQ) were in the ranges of 1.2-1.5 µg/spot and 3.96-4.29 µg/spot, respectively. The developed approach was successfully applied for the determination of FAV in biological (i.e., human urine and plasma) and pharmaceutical samples. The results obtained using the proposed methodology were compared to those obtained using HPLC-UV analysis and found to be in close agreement with one another. Additionally, the green character of the developed method with previously reported protocols was evaluated using the ComplexGAPI, AGREE, and Eco-Scale greenness assessment tools. The proposed method is green in nature and does not require any sophisticated high-end analytical instruments, and it can therefore be routinely applied for the analysis of FAV in various resource-limited laboratories during the COVID-19 pandemic.

Development of the thin film solid phase microextraction (TF-SPME) method for metabolomics profiling of steroidal hormones from urine samples using LC-QTOF/MS

In the present study, the development and optimization of a thin film solid phase microextraction method (TF-SPME) was conducted for metabolomics profiling of eight steroid compounds (androsterone, dihydrotestosterone, dihydroepiandrosterone, estradiol, hydroxyprogesterone, pregnenolone, progesterone and testosterone) from urine samples. For optimization of extraction method, two extraction sorbents (PAN-C18 and PS-DVB) were used as they are known to be effective for isolation of low-polarity analytes. The stages of sample extraction and analyte desorption were considered as the most crucial steps in the process. Regarding the selection of the most suitable desorption solution, six different mixtures were analyzed. As a result, the mixture of ACN: MeOH (1:1, v/v) was chosen in terms of the highest analytes' abundances that were achieved using the chosen solvent. Besides other factors were examined such as the volume of desorption solvent and the time of both extraction and desorption processes. The analytical determination was carried out using the ultra-high performance liquid chromatography coupled with high resolution tandem mass spectrometry detection in electrospray ionization and positive polarity in a scan mode (UHPLC-ESI-QTOF/MS). The developed and optimized TF-SPME method was validated in terms of such parameters as extraction efficiency, recovery as well as matrix effect. As a result, the extraction efficiency and recovery were in a range from 79.3% to 99.2% and from 88.8% to 111.8%, respectively. Matrix effect, calculated as coefficient of variation was less than 15% and was in a range from 1.4% to 11.1%. The values of both validation parameters (recovery and matrix effect) were acceptable in terms of EMA criteria. The proposed TF-SPME method was used successfully for isolation of steroids hormones from pooled urine samples before and after enzymatic hydrolysis of analytes.

Doping in Racing Pigeons (Columba livia domestica): A Review and Actual Situation in Belgium, a Leading Country in This Field

Pigeon racing is a sport in which trained homing pigeons (Columba livia domestica) are released between 60 and 1200 km from their loft and then have to return home as quickly as possible. The first race was held in 1818 in Belgium and since then, Belgium has led the world in pigeon breeding. Unfortunately, as in other sports, doping has become a major issue and doping controls have been implemented. This review provides information about pigeon racing, rules from the Royal Federation Colombophile of Belgium, and laws applicable in Belgium as doping control issues cannot be understood without including them as part of pigeon racing. The main pharmacological data concerning corticoids, non-steroidal anti-inflammatory drugs, anabolic steroids, pain relievers and narcotic analgesics, bronchodilators and β-agonists, drugs acting on the central nervous system and other performance-enhancing drugs, in addition to methods relevant to doping in pigeons are presented. Moreover, the chosen matrix and analytical methods are described.

Recent applications of microextraction sample preparation techniques in biological samples analysis

Analysis of biological samples is affected by interfering substances with chemical properties similar to those of the target analytes, such as drugs. Biological samples such as whole blood, plasma, serum, urine and saliva must be properly processed for separation, purification, enrichment and chemical modification to meet the requirements of the analytical instruments. This causes the sample preparation stage to be of undeniable importance in the analysis of such samples through methods such as microextraction techniques. The scope of this review will cover a comprehensive summary of available literature data on microextraction techniques playing a key role for analytical purposes, methods of their implementation in common biological samples, and finally, the most recent examples of application of microextraction techniques in preconcentration of analytes from urine, blood and saliva samples. The objectives and merits of each microextration technique are carefully described in detail with respect to the nature of the biological samples. This review presents the most recent and innovative work published on microextraction application in common biological samples, mostly focused on original studies reported from 2017 to date. The main sections of this review comprise an introduction to the microextraction techniques supported by recent application studies involving quantitative and qualitative results and summaries of the most significant, recently published applications of microextracion methods in biological samples. This article considers recent applications of several microextraction techniques in the field of sample preparation for biological samples including urine, blood and saliva, with consideration for extraction techniques, sample preparation and instrumental detection systems.

Stepwise optimization and sensitivity improvement of green micellar electrokinetic chromatography method to simultaneously determine some fluoroquinolones and glucocorticoids present in various binary ophthalmic formulations

A sensitive micellar electrokinetic chromatography method is presented to simultaneously quantify ofloxacin, gatifloxacin, dexamethasone sodium phosphate and prednisolone acetate. The method has the advantages of being rapid, accurate, reproducible, ecologically acceptable and sensitive. The electrophoretic separation utilized 20 mm borate buffer as background electrolyte with pH 10.0 ± 0.1 and 50 mm sodium dodecyl sulfate as a micelle forming molecule. A capillary tube (50 μm i.d., 33 cm) of fused silica was used and on-column diode array detection at 243 nm for dexamethasone sodium phosphate and prednisolone acetate, and 290 nm for ofloxacin and gatifloxacin. Various factors were optimized such as the background electrolyte (type, concentration and pH), addition of sodium dodecyl sulfate and its concentration, detection wavelength, applied voltage and injection parameters. The studied drugs were efficiently separated in 6.2 min, at 20 kV with high resolution. The greenness of the method was estimated using an eco-scale tool and the presented method was found to have excellent green characteristics. The method was validated in conformance with International Conference on Harmonization guidelines, with acceptable accuracy, precision and selectivity. The suggested method can be employed for the economic analysis of the four drugs in dissimilar binary combinations of eye drops saving solvents and chemicals.

Recent progress of sample stacking in capillary electrophoresis (2016-2018)

Electrophoretic sample stacking comprises a group of capillary electrophoretic techniques where trace analytes from the sample are concentrated into a short zone (stack). This paper is a continuation of our previous reviews on the topic and brings a survey of more than 120 papers published approximately since the second quarter of 2016 till the first quarter of 2018. It is organized according to the particular stacking principles and includes chapters on concentration adjustment (Kohlrausch) stacking, on stacking techniques based on pH changes, on stacking in electrokinetic chromatography and on other stacking techniques. Where available, explicit information is given about the procedure, electrolyte(s) used, detector employed and sensitivity reached. Not reviewed are papers on transient isotachophoresis which are covered by another review in this issue.

Rapid and sensitive tapered-capillary microextraction combined to on-line sample stacking-capillary electrophoresis for extraction and quantification of two beta-blockers in human urine

A tapered-capillary microextraction (tCap-μEx) combining with field-amplified stacking (FASI) method for CE analysis was developed. The tCap-μEx method is based on the construction of a micro solid phase extraction (SPE) column by narrowing the end of a silica capillary from 530µm (inner diameter) to 20µm, enabling the packing of 45µm sorbent particles without a frit. Various parameters that may affect the microextraction and FASI-CE analysis have been investigated and optimized. This study shows that microextraction exhibits advantages of small sample and sorbent volumes (less than 200μL sample and 2μL sorbent) and fast extraction time of 6min. The method was successfully applied for efficient determination of atenolol and metoprolol in human urine samples, with recovery of 93.7-105.5% and RSD (n=3) lower than 8.5%. Twenty-one-fold and nineteen-fold average enhancement of detection sensitivity was achieved for atenolol and metoprolol, respectively, versus the CE method without tCap-μEx and FASI. The method is environmentally friendly and allows reuse of the sorbent at least 8 times without an obvious loss in performance. The results indicate that the proposed method could be potentially applied in a wide range of doping control, clinical, forensic toxicology, food analysis and environmental analyses.