Solid-phase Extraction Method Research Articles

High enrichment and measurement of heterocyclic aromatic hydrocarbons from environmental waters with magnetic resorcinol-formaldehyde nanocomposites coupled with high performance liquid chromatography

Heterocyclic aromatic hydrocarbons are concerned pollutants with carcinogenic toxicity, which exist universally in various environmental matrices and have great harm to environmental and human health. In present work, magnetic resorcinol-formaldehyde composites (Fe3O4@SiO2@R–F) were fabricated via aldol condensation reaction under alkaline condition. The prepared magnetic materials were examined and analyzed with Fourier transform infrared spectroscopy and other related instruments. The Fe3O4@SiO2@R–F composites were utilized to develop an efficient magnetic solid phase extraction (MSPE) method for extracting six heteropolyclic aromatic hydrocarbons from environmental water samples including carbazole (CB), 7-methylquinoline (7-MQL), 9-methylcarbazole (9-MCB), dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MDBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT). The analytes were analyzed by high performance liquid chromatography-ultraviolet variable wavelength detector (HPLC-VWD). The main factors affecting MSPE were optimized. With the optimal parameters, 9-MCB and 4-MDBT have good linearity over the concentration range of 0.1–300 μg L−1, and 7-MQL, CB, DBT and 4,6-DMDBT have good linearity over the concentration range of 0.5–300 μg L−1. The limits of detection were over the concentration range of 0.012–0.031 μg L−1. This method was successfully employed to measure real waters, and the spiked recoveries ranged from 89.4% to 99.9%. The results confirmed that the developed method was reliable, robust and could be employed as a usefully alternate way for analyzing such pollutants in waters.

High-throughput extraction and automatic purification of alternariol from edible and medicinal herbs based on aptamer-functionalized magnetic nanoparticles.

Mycotoxin contamination is widespread in plants and herbs, posing serious threats to the consumer and human health. Of them, alternariol (AOH) has attracted great attention as an "emerging" mycotoxin in medicinal herbs. However, a specific and high-throughput extraction method for AOH is currently lacking. Thus, developing an efficient pre-treatment technique for AOH detection is extremely vital. Here, a novel automated magnetic solid-phase extraction method was proposed for the highly efficient extraction of AOH. Combining the aptamer-functionalized magnetic nanoparticles (AMNPs) and the automatic purification instrument, AOH could be extracted in medicinal herbs in high throughput (20 samples) and a short time (30min). The main parameters affecting extraction were optimized, and the method was finally carried out by incubation AMNPs with 3mL of sample solution for 10min, and then desorption in 75% methanol for liquid-phase detection. Under optimal conditions, good reproducibility, stability, and selectivity were realized with an adsorption capacity of 550.84ng/mg. AOH extraction in three edible herbs showed good resistance to matrix interference with recovery rates from 86% to 111%. In combination with AMNPs and the automatic purification instrument, high-throughput and labor-free extraction of AOH in different complex matrices was achieved, which could be extended in other complex matrices.

Two-step dual-layer SPE method to separate antibacterial and antioxidant mushroom compounds

We developed a two-step dual-layer solid-phase extraction (SPE) method to separate and concentrate minor bioactive compounds of golden oyster mushroom (Pleurotus citrinopileatus) methanol extract. The mushroom extract is rich in fatty acids, including the highly abundant (20–35 %) and antibacterial linoleic acid. To eliminate the masking effect of linoleic acid in the bioassay, its removal was achieved by homemade dual-layer SPE that consisted of a lower C18 phase and an upper silica gel phase with the dried-on extract. In the first step the elution was performed with water (aqueous eluate), and then the dried C18 and silica gel phases were eluted separately with methanol (C18 methanol eluate and silica gel methanol eluate, respectively). Thin-layer chromatography (TLC)-effect-directed analysis demonstrated that the aqueous eluate contained sugars and antioxidants (TLC-DPPH); fatty acids were present in the silica gel methanol eluate, in the C18 methanol eluate the biologically active minor secondary metabolites were concentrated (TLC–Bacillus subtilis assay) beside 2 % remained linoleic acid according to HPLC-UV measurement. As a result, the antioxidant and antibacterial metabolites divided, and the low-abundant antibacterial compounds could be detected. Based on this study, the substance found at RF 0.25 by TLC-DPPH played the most significant role in generating the antioxidant effect of the aqueous eluate, equivalent to 5.07 ± 0.09 µg of gallic acid. Moreover, each SPE fraction and raw extract were tested for antibacterial effect using a microplate assay with a non-pathogenic Gram-positive Bacillus subtilis. The P. citrinopileatus extract (MIC-value – 50 µg/mL) and C18 methanol eluate (MIC-value - 25 µg/mL) inhibited the growth of B. subtilis while the other eluates did not.

Selective Extraction of Diazepam and Its Metabolites from Urine Samples by a Molecularly Imprinted Solid-Phase Extraction (MISPE) Method.

In this research, a molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization using oxazepam (OZ) as a template molecule and was subsequently applied as a selective sorbent for the extraction of diazepam (DZP) and its metabolites in urine samples using an SPE cartridge. OZ, temazepam (TZ), nordiazepam (NZ) and DZP were analyzed in the final extracts by high-performance liquid chromatography with diode array detection (HPLC-DAD). The SPE extraction steps were optimized, and the evaluation of an imprinting factor was carried out. The selectivity of the method for OZ versus structurally related benzodiazepines (BZDs), such as bromazepam (BRZ), tetrazepam (TTZ) and halazepam (HZ), was investigated. Under the optimum conditions, the proposed methodology provided good linearity in the range of 10-1500 ng/mL, with limit of detection values between 13.5 and 21.1 ng/mL and recovery levels for DZP and its metabolites from 89.0 to 93.9% (RSD ≤ 8%) at a concentration level of 1000 ng/mL. The proposed method exhibited good selectivity, precision and accuracy and was applied to the analysis of urine samples from a real case of DZP intake.

Trace Determination of Phenanthrene and Fluorene in Beverages Using D-μ-SPE and Liquid Chromatography Analysis

Dispersive micro solid phase extraction (D-μ-SPE) method using Graphene Oxide (GO) for the extraction and pre-concentration of selected polycyclic aromatic hydrocarbons (PAHs) from beverage samples prior to high-performance liquid chromatography - diode array detector (HPLC - DAD) is reported. Selected PAHs Fluorene (FLU) and Phenanthrene (PHE) were used as targeted analytes. An experimental design using Response Surface Methodology (RSM) and Box–Box–Behnken design (BBD) was performed to evaluate the interactive effects of three significant parameters: mass of sorbent, sample volume and extraction time. Under the optimum conditions, the method revealed good linearity (R2 = 0.9995 – 0.9998) over a concentration range of 0.5 – 5.0 mg L-1. The limit of detection (LOD) was in the range of 0.03 – 0.24 mg L-1 with satisfactory relative recoveries (81 – 99 %) and good relative standard deviation (RSD) of ≤ 3.80 % (n = 3). The method was successfully applied to tea, coffee, and milk samples and proved to be a simple, rapid, and reliable method with good extraction efficiencies for the detection of PAHs in beverage samples.

A new methodology to reveal potential nucleic acid modifications associated with the risk of endometrial cancer through dispersive solid-phase extraction coupled with UHPLC-QE-Orbitrap-MS/MS and HPLC-UV.

Nucleic acid modifications have attracted increasing attention in recent years since they have been found to be related to a number of diseases including cancer. Previous studies have shown that the early development of endometrial cancer (EC) is often accompanied by changes in methylation levels of related genes, and the expression of related proteins that regulate reactive oxygen species (ROS) shows significant differences in EC cells and tissues. However, it has not been reported whether nucleic acid modifications related to methylation or ROS can serve as biomarkers for EC. Accurate quantification of these nucleic acid modifications still has challenges because their amounts in urine are very low and the interferences in urine are complicated. In this study, a novel dispersive solid-phase extraction (DSPE) method based on chitosan-carbon nanotube-Al2O3 (CS-CNT-Al2O3) has been established for the analysis of 5-hydroxymethyluracil (5mU), 5-methyl-2'-deoxycytidine (5-mdC), 5-hydroxymethyl-2'-deoxycytidine (5-hmdC), 5-formyl-2'-deoxycytidine (5-fdC), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in EC patient urine samples coupled with UHPLC-QE-Orbitrap-MS/MS and HPLC-UV. Firstly, the synthesis of the CS-CNT-Al2O3 nanocomposite was conducted by a sono-coprecipitation method and was characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and Fourier transform infrared (FTIR). Under the optimal extraction conditions of DSPE, we successfully quantified 5mU, 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG in urine samples from 37 EC patients and 39 healthy controls. The results showed that there were significant differences in the levels of 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG in EC patients compared to the healthy control group. The receiver operator characteristic (ROC) curve analysis was carried out to evaluate the potential of 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG to distinguish EC patients from healthy volunteers. The area under the curve (AUC) for 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG was 0.7412, 0.667, 0.8438, and 0.7981, respectively. It indicated that 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG had certain potential in distinguishing between EC patients and healthy volunteers and they could act as potential non-invasive biomarkers for early diagnosis of EC. Moreover, the present study would stimulate investigations of the effects of nucleic acid modifications on the initiation and progression of EC.

Changes in Concentrations of Polyfluoroalkyl Substances in Human Milk Over Lactation Time and Effects of Maternal Exposure via Analysis of Matched Samples.

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are potentially related to many adverse health outcomes and could be transferred from maternal blood to human milk, which is an important exposure source for infants during a long-term period. In this study, the maternal blood of 76 women after delivery and their matched human milk samples obtained at 0.5, 1, and 3 months were analyzed by solid-phase extraction method with metal-organic framework/polymer hybrid nanofibers as the sorbents and ultrahigh-performance liquid chromatography-negative electrospray ionization mass spectrometric for quantitative analysis of 31 PFAS. The perfluorooctanoic acid, perfluorooctane sulfonate, and N-methyl perfluorooctane sulfonamido acetic acid (N-MeFOSAA) contributed to more than approximately 50% of the total PFAS concentrations in blood and human milk, while N-MeFOSAA (median: 0.274 ng/mL) was the highest PFAS in human milk at 3 months. The transfer efficiencies for PFAS from maternal blood to human milk at 0.5 months were generally lower, with medians ranging from 0.20% to 16.9%. The number of PFAS species detected in human milk increased as the lactation time went on from 0.5 to 3 months, and the concentrations of 10 PFAS displayed an increasing trend as the prolongation of lactation time (p < 0.05).

A Fast and Simple Solid Phase Extraction-Based Method for Glucosinolate Determination: An Alternative to the ISO-9167 Method.

Glucosinolates (GLSs) are a well-studied sulfur-containing compound found in Brassicaceae plants that play critical roles in plant resistance and human health. Correctly identifying and reliably quantifying the total and individual GLS content is of great importance. An improved method as an alternative to the ISO 9167-1 (ISO) method is developed in the present study. An efficient extraction and purification procedure is proposed with a commercially available dimethylaminopropyl (DEA)-based weak anion exchange solid-phase extraction (SPE) cartridge instead of using the self-prepared ion-exchange columns in the ISO method. The GLSs are identified and quantified by ultra high-performance liquid chromatography (UHPLC) high-resolution mass spectrometry (HRMS). The method demonstrates a comparable quantification of total and individual GLSs on certified rapeseeds and other Brassicaceae vegetables when compared to the ISO method. The developed SPE method is simpler and more efficient, thus allowing for applications to a large sample size with reduced analysis time, improved repeatability and accuracy, and possible automation.

Development of a continuous magnetic dispersive solid phase extraction method for the extraction of seven widely used pesticides from fruit juices

Generally, food safety monitoring is vital issue to preserve human health and guarantee a longer lifespan. In present study, a continuous mode of magnetic dispersive solid phase extraction method based on using magnetic covalent organic framework@metal organic framework nanocomposite as sorbent has been proposed. The developed method has been tested for the extraction of some pesticides (pirimicarb, terbutryn, fenthion, triticonazole, hexaconazole, diniconazole, and haloxyfop-R-methyl) from commercial fruit juices prior to their analysis by high performance liquid chromatography–tandem mass spectrometry. In the current research, the properties of nanocomposite were characterized by scanning electron microscopy, Fourier–transform infrared spectrophotometry and X–ray diffraction techniques. In the next step, the synthesized nanocomposite was employed as an efficient sorbent in the developed extraction procedure that was done in a narrow bore tube. Under optimum extraction conditions, extraction recoveries were in the ranges of 67–83 %. Moreover, the limits of detection and quantification of the selected analytes were in the ranges of 17–43 and 56–143 ng L−1, respectively. Finally, the proposed method was successfully applied in the analysis of the opted pesticides in sixty fruit juice samples.

Previtamin D2, vitamin D2, and vitamin D4 amounts in different mushroom species irradiated with ultraviolet (UV) light and occurrence of structurally related photoproducts

AbstractMushrooms are rich in ergosterol and ergosta‐5,7‐dienol, which can be partly converted into vitamin D2 and D4 through ultraviolet (UV) light exposure. Typically, mushrooms have very low vitamin D contents, but it can be increased by UV irradiation. This process generates additional photoisomers scarcely studied in mushrooms due to analytical challenges. Here, we developed a new solid phase extraction (SPE) method to separate vitamin D2, vitamin D4, and other tri‐ and pentacyclic photoisomers from the much higher abundant ergosterol. Subsequent GC/MS analysis enabled the detection of ten photoisomers in eight UV‐treated mushroom species, including vitamin D2 (previtamin D2, tachysterol2, two suprasterol2 and trans‐vitamin D2 isomers) and vitamin D4 (previtamin D4). Quantitated vitamin D2 contents of 10–540 µg/100 g dry weight agreed well with the sparse literature data available for the investigated mushroom species. In addition, previtamin D2 (nd–1950 µg/100 g dry weight) and vitamin D4 (10–140 µg/100 g dw) were quantified in the samples. The content and photoproduct compositions varied considerably between different mushroom species.Practical applications: The novel SPE method can be applied to study the vitamin D and photoisomer content of mushrooms.

First Report on a 1-Cycle Solid-Phase Extraction Method for Selective Separation of Am3+ and Eu3+: Use of BTP-Grafted Silica Decorated on Activated Carbon

First Report on a 1-Cycle Solid-Phase Extraction Method for Selective Separation of Am³⁺ and Eu³⁺: Use of BTP-Grafted Silica Decorated on Activated Carbon

Screening and confirmation of psilocin, mitragynine, phencyclidine, ketamine and ketamine metabolites by liquid chromatography-tandem mass spectrometry.

A safe and productive workplace requires a sober workforce, free from substances that impair judgment and concentration. Although drug monitoring programs already exist, the scope and loopholes of standard workplace testing panels are well known, allowing other substances to remain a source of risk. Therefore, a high-throughput urine screening method for psilocin, mitragynine, phencyclidine, ketamine, norketamine and dehydronorketamine was developed and validated in conjunction with a urine and blood confirmation method. There are analytical challenges to overcome with psilocin and mitragynine, particularly when it comes to drug stability and unambiguous identification in authentic specimens. Screening and confirmation methods were validated according to the American National Standards Institute/Academy Standards Board (ANSI/ASB) Standard 036, Standard Practices for Method Validation in Forensic Toxicology. An automated liquid handling system equipped with dispersive pipette extraction tips was utilized for preparing screening samples, whereas an offline solid-phase extraction method was used for confirmation sample preparation. Both methods utilized liquid chromatography-tandem mass spectrometry to achieve limits of detection between 1-5 ng/mL for the screening method and 1 ng/mL for the confirmation method. Automation allows for faster throughput and enhanced quality assurance, which improves turnaround time. Compared to previous in-house methods, specimen volumes were substantially decreased for both blood and urine, which is an advantage when volume is limited. This screening technique is well suited for evaluating large numbers of specimens from those employed in safety-sensitive workforce positions. This method can be utilized by workplace drug testing, human performance and postmortem laboratories seeking robust qualitative screening and confirmation methods for analytes that have traditionally been challenging to routinely analyze.

Evaluation of an Oral Fluid Collection Device and a Solid-Phase Extraction Method for the Determination of Coca Leaf Alkaloids by Gas Chromatography-Mass Spectrometry.

Some South American countries have ancient traditions that may pose legal problems, such as the consumption of coca leaves, as this can provide positive results for cocaine use after the analysis of biological samples. For this reason, it is necessary to find specific markers that help differentiate legal from illegal consumption, such as tropacocaine, cinnamoylcocaine, and especially hygrine and cuscohygrine. In this work, two techniques for collecting biological samples are compared: the Quantisal® Oral Fluid collection device and passive drooling. Once the samples were collected, they were subjected to solid-phase extraction for subsequent injection into GC-MS. Different validation parameters included in international guides have been studied to evaluate whether the proposed method is valid for the defined purpose, placing special emphasis on the study of the matrix effect and little value on GC-MS analyses. With respect to this parameter, an increase in the signal was found for CUS and t-CIN, but it was not significant for the rest of the substances studied. The recoveries have varied significantly depending on the way of working, being higher when working with standardized areas. After carrying out work with the oral fluid samples collected from laboratory volunteers, the method was applied to two real samples. The results obtained support the need for further research to overcome certain limitations presented by the device.

Simultaneous determination of multiple urine biomarkers for kidney injury using SPE combined with LC-MS/MS

Background and ObjectivesUrinary biomarkers such as low molecular weight proteins and small molecular weight metabolites are crucial in the diagnosis of kidney injury. The objective of this study was to develop and preliminarily validate a sensitive and specific method using solid-phase extraction (SPE) in conjunction with liquid chromatography–tandem mass spectrometry (LC-MS/MS) for the simultaneous measurement of these biomarkers in human urine. MethodThis study presents the development of a solid-phase extraction method integrated with LC-MS/MS analyzing biomarkers including creatinine, urea, β2-microglobulin, α1-microglobulin, and cystatin C in human urine. An enhanced solid-phase cartridge technique was employed for peptide purification and dilution of small molecule metabolites during sample preparation. ResultsThe developed LC-MS/MS method achieved satisfactory separation of the five analytes within 15 min. Accuracy levels ranged from −8.6% to 13.6%. Both intra-assay and inter-assay imprecision rates were maintained below 7.9% for all analytes. ConclusionsThe established LC-MS/MS method effectively quantifies creatinine, urea, β2-microglobulin, α1-microglobulin and cystatin C concurrently. This offers a viable alternative for the detection of kidney injury biomarkers in human urine, demonstrating potential for clinical application in kidney injury diagnosis.

Application of magnetic dispersive solid phase extraction combined with solidification of floating organic droplet-based dispersive liquid–liquid microextraction and GC-MS in the extraction and determination of polycyclic aromatic hydrocarbons in honey

A magnetic dispersive solid phase extraction method combined with solidification of floating organic droplet-based dispersive liquid–liquid microextraction has been validated for the extraction of polycyclic aromatic hydrocarbons from honey samples. For this purpose, a carbonised cellulose–ferromagnetic nanocomposite was used as a sorbent through the magnetic dispersive solid phase extraction. For preparation of the sorbent, first, carbonised cellulose nanoparticles were created by treating cellulose filter paper with concentrated solution of sulfuric acid. Then, the prepared nanoparticles were loaded onto Fe3O4 nanoparticles through coprecipitation. In the extraction process, first, a few mg of the sorbent was added to the diluted honey solution and dispersed in it using vortex agitation. The particles were then separated and the adsorbed analytes were eluted with an organic solvent. The eluent was taken and after mixing with a water–immiscible extraction solvent was used in the following solidification of floating organic droplet-based dispersive liquid–liquid microextraction procedure. By performing the extraction process under the obtained optimum conditions, low limits of detection (0.08–0.17 ng g−1) and quantification (0.27–0.57 ng g−1), satisfactory precision (relative standard deviations ≤ 5.0%), and wide linear range (0.57–500 ng g−1) with great coefficients of determination (r2≥ 0.9986) were obtained.

A novel removal of Ni2+ ions from water solutions using dispersive solid-phase extraction method with nano Fe3O4/chitosan-acrylamide hydrogel.

The effluent release containing heavy metals as Ni2+ ions has drastic risks to both the natural environment and human health. In this research, the nano Fe3O4/chitosan-acrylamide hydrogel was prepared as a novel nano sorbent for dispersive solid-phase extraction of Ni2+ ions and applied to the water sample solution. The pH, amount and type of elution solvent, the extraction time, etc. were optimized to improve the efficiency of the proposed method. Analytical parameters such as concentration factor and relative standard deviation (%) were achieved as 33.3 and 1.8%, respectively. The capacity in equilibrium sorption was calculated at 22.54 mg g-1. Furthermore, to estimate the adsorption mode, Freundlich, Langmuir, and Temkin models were fitted with experimental isotherm data. Besides, to check the basic process of the metal adsorption mechanism, pseudo-first-order, pseudo-second-order, and Roginsky-Zeldovich models were investigated and the results were fitted with the pseudo-second-order model. The value of change in entropy (⊿S) obtained is -65.24 (J(mol K)-1). Negative values of change in enthalpy, ⊿H in (kJ mol-1) is -24.45 (kJ mol-1) which indicates both physical and chemical adsorptions involved in the process of adsorption. Finally, the nano Fe3O4/chitosan-acrylamide hydrogel exhibited high performance to remove the Ni2+ ions from water sample solution.

Analysis of Vaccenic and Elaidic acid in foods using a silver ion cartridge applied to GC × GC-TOFMS.

Trans fatty acids (TFAs) are unsaturated fatty acids, with vaccenic acid (VA) and elaidic acid (EA) being the major constituents. While VA has been associated with beneficial effects on health and anti-cancer properties, EA is found in hardened vegetable oils and is linked to an increased risk of cardiovascular diseases. Therefore, this study aimed to develop a novel method for the quantitative measurement of VA and EA, aiming to accurately analyze individual TFA and apply it for the assessment of products containing TFAs. The ratio of VA to EA (V/E ratio) was evaluated using a silver ion cartridge (SIC) solid phase extraction method removing cis-fatty acids (cis-FAs). Additionally, comparative analysis of the V/E ratio was conducted by the two methods (SIC treatment and untreated) using comprehensive two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GC × GC-TOFMS). The removal efficiency of cis-FAs was greater than 97.8%. However, the total TFA contents were not so different from SIC treatment. Moreover, this approach not only allowed for a more precise determination of the V/E ratio but also revealed a significant distinction between natural trans fatty acids (N-TFAs) and hydrogenated trans fatty acids (H-TFAs). Therefore, the SIC coupled to the GC × GC-TOFMS presented in this study could be applied to discriminate N-TFA and H-TFA contents in dairy and fatty foods.

A simple and effective graphene oxide-zinc oxide nanocomposite based solid phase extraction method for the determination of cadmium in tea matrix at trace levels by flame atomic absorption spectrophotometry

In this study, an easy, environmentally friendly and fast approach was introduced for the synthesis of GO-ZnO nanocomposite (NC). Characterization tools including X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) were used to verify the synthesized nanomaterial. Afterward, the combination of GO-ZnO NC based dispersive solid phase microextraction (dSPME) and flame atomic absorption spectrophotometry (FAAS) was used to preconcentrate and determine Cd with high precision and accuracy. In the optimization experiments, all parameters that affecting extraction yield were optimized. Limit of quantification (LOQ) and detection (LOD) values for the GO-ZnO NC-dSPME-FAAS system were calculated as 12.76 µg L−1 and 3.83 µg L−1, respectively. In order to check the applicability and accuracy of the developed method, recovery experiments were performed on three different hibiscus tea samples. The percent recovery values calculated from the spike experiments were in the range of 84 – 111%.

Speciation of Chromium by Magnetic Solid Phase Microextraction Using an Activated Charcoal-Molybdenum (IV) Selenide-Magnetite Composite with Flame Atomic Absorption Spectrometric (FAAS) Detection

A simple and sensitive magnetic solid phase extraction (MSPE) method was developed for the separation-preconcentration and speciation of Cr in water samples. The system is based on the adsorption of Cr (VI)-ammonium pyrrolidinedithiocarbamate (APDC) complex on the activated charcoal@MoSe2@Fe3O4 composite. Total chromium has also been determined after the conversion of Cr (III) to Cr (VI) by oxidation with KMnO4. Cr (III) was determined as the difference between the total content of the Cr and Cr (VI). For quantitative recoveries, the effects of solution pH, adsorbent amount, volume of the sample, ligand volume, eluent type, and volume and effect of foreign ions were investigated. The limit of detection and limit of quantification for Cr was 0.36 ng mL−1 and 1.19 ng mL−1, respectively. The procedure was applied for the determination and speciation of chromium in water samples.

UPLC METHOD DETERMINATION AND QUANTIFICATION OF BELUMOSUDIL AND ITS IMPURITIES IN THE HUMAN PLASMA SAMPLES

This current analysis demonstrates the development of the related substances (RS) method for separating and quantifying BSL and its related substances from plasma using the UPLC technique. The solid phase extraction (SPE) method was employed to extract the belumosudil (BSL) and related impurities from plasma. This SPE method has been shown to have high recovery values for BSL and its related impurities. The method employed a column from Waters, specifically the X-Bridge BEH C18 150x4.6mm, 3.5µm, with a mobile phase flow rate (0.8 mL/min) and a UV-wavelength (250 nm). In this method, BSL and its impurities show good peak shapes and high resolutions. This developed method shows high sensitivity, accuracy, and precision values. While performing the stability studies, the drug was stable and it showed less than 4.53% degradation. Six different concentration solutions (BSL (25-250µg/mL) and impurities (3-18µg/mL)) were prepared for constructing linearity plots. The obtained linearity plot shows the accepted correlation coefficient (R2) value (≥0.999). The Limit of detection (LOD) and Limit of quantification (LOQ) were determined using the signal-to-noise (S/N) ratio method. This UPLC method was validated according to ICH guidelines.