Simultaneous Determination Research Articles

Determination of pesticide residues and heavy metals in Adhatoda Vasaka Linn.

Heavy metals and pesticide residue analysis plays an important role in the quality control of medicinal plants like Vasaka (Adhatoda vasica). Hence a study was conducted to determine heavy metals and pesticide residues in this medicinal herb, which is a highly useful commodity in the health system. The reliable, rapid and nontoxic sample preparation method like QuEChERS and analytical methods like GC-MS were proposed for the simultaneous determination of pesticide residues and Heavy metal detection was carried out by ICP-MS. In this study, the presence of organophosphorus and organochlorine pesticides like alachlor, heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, etc was checked but not detected. Heavy metals like Arsenic (As), Cadmium (Cd), Mercury (Hg) and Lead (Pb) are traced in samples about 2.3005 ppb, 0.799 ppb, 2.290 ppb and 10.204 ppb respectively in the present study.

Thiol-based chemically modified carbon screen-printed electrode for simultaneous quantification of trace level Pb(II) and Cd(II).

Present work reports, the development of a novel electrochemical sensor based on a diazonium-coupling reaction and covalent attachment of the -NH2 group of cysteamine (Cyst) on screen-printed carbon electrode (SPCE), for simultaneous determination of Pb(II) and Cd(II). Initially, the in-situ generated 4-carboxyphenyl (4-CP) diazonium salt was electro-grafted to generate 4-CP/SPCE, followed by covalent bonding of terminal carboxylic group of 4-CP with -NH2 group of Cyst to give Cyst/4-CP/SPCE. The modified electrode showed an enhanced selectivity and sensitivity toward the quantification of Pb(II) and Cd(II) using square wave anodic stripping voltammetry (SWASV) without mutual interference. Under optimal experimental conditions, the newly designed sensor showed a wide linear range of 0.01µM to 0.7µM. The limit of detection (LOD) obtained was 0.882nM (0.09 ppb) and 0.65nM (0.134ppb) for Cd(II) and Pb(II), respectively. The modified SPCE exhibited good stability, selectivity, and reproducibility. Furthermore, the sensor was successfully applied for the determination of Pb(II) and Cd(II) ions in water samples which illustrated excellent recoveries in different spiked samples and the results were in line with the standard ICP-AES analysis.

Top-down mass spectrometry of native proteoforms and their complexes: a community study.

The combination of native electrospray ionization with top-down fragmentation in mass spectrometry (MS) allows simultaneous determination of the stoichiometry of noncovalent complexes and identification of their component proteoforms and cofactors. Although this approach is powerful, both native MS and top-down MS are not yet well standardized, and only a limited number of laboratories regularly carry out this type of research. To address this challenge, the Consortium for Top-Down Proteomics initiated a study to develop and test protocols for native MS combined with top-down fragmentation of proteins and protein complexes across 11 instruments in nine laboratories. Here we report the summary of the outcomes to provide robust benchmarks and a valuable entry point for the scientific community.

Development and Validation of a RP-HPLC Method for the Simultaneous Determination of Silver Sulfadiazine and Sodium Hyaluronate in the Presence of Methyl and Propyl Paraben in a Pharmaceutical Cream for Burns.

A direct and precise isocratic RP-HPLC method for simultaneous determination of silver sulfadiazine (SSD) and sodium hyaluronate (SH) in the presence of methyl (MP) and propyl parabens (PP) was developed and validated. Agilent chromatograph with X-Select C18 column (250 × 4.6mm2, 5μm) was used. Chromatographic separation was achieved using a mobile phase consisting of acetonitrile and 0.05M phosphate buffer (pH5.0 to which added triethyl amine 0.5ml/L), at a ratio 35: 65v/v. Elution was used at flow rate of 1.0mL/min at ambient temperature with UV detection at 205nm. The retention times for SH, SSD, MP and PP were 1.49, 3.3, 6.7 and 19.5min, respectively. The presented chromatographic method was fully validated in accordance with ICH requirements, it was valid over linearity ranges of (0.80-100.00μg/mL) and (3.20-100.00μg/mL) for SSD and SH, respectively. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges and the sensitivity of the method, as the limits of detection and quantification for each active ingredient was also determined. The validated method was successfully applied for the quantification of SSD and SH in pharmaceutical cream formulation and the mean recovery %±SD were 100.93 ± 0.985 and 100.05 ± 0.668 for SSD and SH; respectively, indicating satisfactory accuracy of the method.

Electrochemical syntheses and characterization of some polydyes and their application for the simultaneous determination of ascorbic acid and uric acid

Electrochemical syntheses and characterization of some polydyes and their application for the simultaneous determination of ascorbic acid and uric acid

Simultaneous determination of five plant hormones in cotton leaves using QuEChERS combined with HPLC‒MS/MS

BackgroundPlant hormones profoundly influence cotton growth, development, and responses to various stresses. Therefore, there is a pressing need for an efficient assay to quantify these hormones in cotton. In this groundbreaking study, we have established QuEChERS-HPLC‒MS/MS method, for the simultaneous detection of multiple plant hormones in cotton leaves, allowing the analysis and quantification of five key plant hormones.ResultsSample extraction and purification employed 0.1% acetic acid in methanol and C18 for optimal recovery of plant hormones. The method applied to cotton demonstrated excellent linearity across a concentration range of 0.05–1 mg·L−1, with linear regression coefficients exceeding 0.99. The limits of quantification (LOQs) were 20 μg·kg−1 for GA3 and 5 μg·kg−1 for the other four plant hormones. Recovery rates for the five plant hormones matrix spiked at levels of 5, 10, 100, and 1000 μg·kg−1 were in the range of 79.07% to 98.97%, with intraday relative standard deviations (RSDs) ranging from 2.11% to 8.47%. The method was successfully employed to analyze and quantify the five analytes in cotton leaves treated with plant growth regulators.ConclusionThe study demonstrates that the method is well-suited for the determination of five plant hormones in cotton. It exhibits excellent selectivity and sensitivity in detecting field samples, thus serving as a robust tool for in-depth research into cotton physiology.

A Rapid and Accurate UHPLC Method for Determination of Monosaccharides in Polysaccharides of Different Sources of Radix Astragali and Its Immune Activity Analysis

With the escalating demand for Astragalus polysaccharides products developed from Radix Astragali (RA), the necessity for quality control of polysaccharides in RA has become increasingly urgent. In this study, a specific method for the simultaneous determination of seven monosaccharides in polysaccharides extracted from Radix Astragali (RA) has been developed and validated using ultra-performance liquid chromatography equipped with an ultraviolet detector (UHPLC-UV) for the first time. The 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatizations were separated on a C18 column (Waters ACQUITYTM, Milfor, MA, USA, 1.8 µm, 2.1 × 100 mm) using gradient elution with a binary system of 5 mm ammonium formate (0.1% formic acid)-acetonitrile for 24 min. Additionally, seven monosaccharides showed good linear relationships (R2, 0.9971–0.9995), adequate precision (RSD < 4.21%), and high recoveries (RSD < 4.70%). The established method was used to analyze 109 batches of RA. Results showed that the Astragalus polysaccharides (APSs) mainly consist of mannose (Man), rhamnose (Rha), glucose (Glu), galactose (Gal), arabinose (Ara), xylose (Xyl); and fucose (Fuc); however, their composition was different among RA samples from different growth patterns, species, growth years, and origins, and the growth mode of RA and the age of wild-simulated RA can be accurately distinguished by principal component analysis (PCA). In addition, the immunological activity of APSs were also evaluated jointly by measurement of the NO release with RAW264.7, with the results showing that APSs have a promoting effect on the release of NO and exhibit a significant correlation with Man, Glu, Xyl, and Fuc contents. Accordingly, the new established monosaccharides analytical method and APS-immune activity determination in this study can provide a reference for quality evaluation and the establishment of quality standards for RA.

Rapid and Comprehensive Analysis of 41 Harmful Substances in Multi-Matrix Products by Gas Chromatography–Mass Spectrometry Using Matrix-Matching Calibration Strategy

Harmful substances in consumer goods pose serious hazards to human health and the environment. However, due to the vast variety of consumer goods and the complexity of their substrates, it is difficult to simultaneously detect multiple harmful substances in different materials. This paper presents a method for the simultaneous determination of 41 harmful substances comprising 17 phthalates (PAEs), 8 organophosphate flame retardants (OPFRs), and 16 polycyclic aromatic hydrocarbons (PAHs) in five types of products using the matrix-matching calibration strategy. The method employs an efficient ultrasonic extraction procedure using a mixture of dichloromethane and methylbenzene, followed by dissolution–precipitation and analysis through gas chromatography–mass spectrometry. Compared with previous experiments, we established a universal pretreatment method suitable for multi-matrix materials to simultaneously determine multiple harmful substances. To evaluate the effects of the matrix on the experimental results, we compared neat standard solutions and matrix-matching standard solutions. The results demonstrated that all compounds were successfully separated within 30 min with excellent separation efficiency. Additionally, the linear relationships of all analytes showed strong correlation coefficients (R2) of at least 0.995, ranging from 0.02 mg/L to 20 mg/L. The average recoveries of the target compounds (spiked at three concentration levels) were between 73.6 and 124.1%, with a relative standard deviation (n = 6) varying from 1.2% to 9.9%. Finally, we tested 40 different materials from consumer products and detected 16 harmful substances in 31 samples. Overall, this method is simple and accurate, and it can be used to simultaneously determine multiple types of hazardous substances in multi-matrix materials by minimizing matrix effects, making it an invaluable tool for ensuring product safety and protecting public health.

A validated high‐performance liquid chromatography‐tandem mass spectrometry method for simultaneous determination of irinotecan and two major metabolites in rat plasma: Application for the pharmacokinetics study

AbstractA high‐performance liquid chromatography‐tandem mass spectrometry method has been developed for the determination of irinotecan, 7‐ethyl‐10‐hydroxycamptothecin (SN38), and SN38 glucuronide (SN38G) in rat plasma in the present study. The analytes were separated on a C18 column and a triple‐quadrupole mass spectrometry equipped with an electrospray ionization source was applied for detection. Irinotecan, SN38 and SN38G could be well retained in the C18 column after optimization of mobile phase. A simple protein precipitation was used to pretreat the plasma. The extraction recovery was above 90% and the matrix effect could be negligible. The method was linear over the concentration ranges of 3.46–3458.8 ng/mL for irinotecan, 2.53–2530.0 ng/mL for SN38 and 2.5–2500.0 ng/mL for SN38G. The precision and accuracy was within the acceptable limits. The simple and convenient method was validated and successfully applied to support the pharmacokinetic study and elucidate the mechanism of irinotecan‐induced diarrhea after irinotecan was intravenously injected to the Sprague‐Dawley rats.

Development and validation of a UHPLC-ESI-MS/MS method for the simultaneous determination of organic acids and phenolic compounds in Filipendula vulgaris, Polygonum divaricatum, Hypericum linarioides, and Rheum ribes

This research focused on investigating biologically active and pharmaceutically important phytochemicals using reliable and reproducible analytical techniques specifically designed for traditional medicinal plants. Considering the complex chemical diversity present in plant extracts, reliable identification methods are crucial. The goal of this study was to develop and validate a robust UHPLC-ESI-MS/MS method for the qualitative and quantitative analysis of organic acids (OAs) and phenolic compounds (PCs). With gradient elution of water containing 0.1 % formic acid and acetonitrile containing 0.1 % formic acid as the mobile phase, OAs and PCs were separated chromatographically on a C18 reversed-phase column. Through the use of an electrospray ionization source operating in negative ionization mode, these compounds were identified on a triple quadrupole tandem mass spectrometer. The validation results clearly indicate that the method exhibited linearity with a squared correlation coefficient (R2 ≥ 0.9986), demonstrating sensitivity (LOQ: 1.08 µg/L-10.79 µg/L), precision (RSD%≤2.73), and trueness (RE% ≤ 1.53) for the OAs and PCs found in the plants. The developed UHPLC-ESI-MS/MS method was successfully applied to the qualitative and quantitative analysis of OAs and PCs in Turkish plants, which are commonly used in traditional medicine. Our study identified a total of 12 OAs and PCs in F. vulgaris, 12 in P. divaricatum, 9 in H. linarioides, and 11 in R. ribes. In particular, gallic acid had the highest content in F. vulgaris (925.67 µg/g extract) and R. ribes (1358.78 µg/g extract), while H. linarioides (730.66 µg/g extract) and P. divaricatum (4003.02 µg/g extract) had relatively high levels of quinic acid. In conclusion, the developed UHPLC-ESI-MS/MS method allows the simultaneous analysis and quantification of 2 OAs and 33 PCs in plants and proves to be a valuable tool for evaluating the efficacy of traditional medicinal plants.

Rapid and simultaneous determination of curcuminoids and gingerols in food products containing turmeric and ginger using paper spray mass spectrometry.

Turmeric and ginger are extensively employed as functional ingredients due to their high content of curcuminoids and gingerols, considered the key bioactive compounds found in these roots. In this study, we present an innovative and fast method for the assay of curcuminoids and gingerols in different foods containing the two spices, with the aim of monitoring the quality of products from a nutraceutical perspective. The proposed approach is based on paper spray tandem mass spectrometry coupled with the use of a labeled internal standard, which has permitted to achieve the best results in terms of specificity and accuracy. All the calculated analytical parameters were satisfactory; accuracy values are around 100% for all spiked samples and the precision data result lower than 15%. The protocol was applied to several real samples, and to demonstrate its robustness and reliability, the results were compared to those arising from the common liquid chromatographic method.

Simultaneous determination of eight neonicotinoid insecticides and five metabolites in water samples by liquid chromatography‐tandem mass spectrometry unveils an overlooked risk

AbstractNeonicotinoids (NEOs), highly selective toward insect nicotinic acetylcholine receptors, are extensively used due to their effectiveness against pests and relative non‐toxicity to vertebrates. However, their prolonged persistence in soil and water has led to frequent detection in food and environmental samples, posing significant environmental and health concerns. Recent research indicates these pesticides infiltrate aquatic ecosystems, threatening aquatic life and human health. Here, we improved the ultra‐performance liquid chromatography‐mass spectrometry method for detecting NEOs in water samples, increasing its sensitivity to fulfill forthcoming detection needs. This approach enables the simultaneous quantification of eight NEOs and five NEO metabolites in diverse water sources, including tap, surface, groundwater, sewage, and seawater. Our method achieves remarkably low detection limits for direct injection (0.78–1.7 ng/L) and solid‐phase extraction methods (0.13–0.25 ng/L). Critically, our findings reveal that boiling domestic drinking water doesn't degrade NEOs; instead, it increases their concentration due to water evaporation. A 6‐min boiling period can amplify pesticide concentration by 4–5 times, presenting a significant hazard in culinary practices of specific regions where prolonged cooking could lead to alarmingly high levels of these insecticides. This research underscores the importance of monitoring and mitigating NEO contamination in water sources to safeguard environmental and public health.

Simultaneous estimation of mometasone furoate and olopatadine hydrochloride by reversed‐phase high‐performance liquid chromatography

AbstractThe simultaneous determination of Mometasone furoate (MOM) and Olopatadine hydrochloride (OLO) in a combined dose has been developed and validated using a specific, precise, accurate, fast, reliable, and economical high‐performance liquid chromatography technique. Methanol:water:acetonitrile (20:25:55, v/v/v) was used as the mobile phase during the separation. The procedure was performed using a low‐pressure gradient elution on the reversed‐phase Phenomenex C18 column. At 238 nm, separated components were densitometrically measured. The flow rate was fixed at 1.0 mL/min with a continuous run up to 10 min, while the retention time was located near about 3.2 and 6.1 min for OLO and MOM, respectively. The method was validated for Linearity and range, precision, reproducibility, specificity, accuracy, limit of detection, limit of quantification, and robustness as per the International Council for Harmonization Q2(R1) guideline. MOM and OLO regression coefficients (r2) were found to be 0.9994 and 0.9997, over the range of 2.5–15 and 33.25–199.5 µg/mL, respectively. MOM and OLO percentage recoveries were measured to be 99.49 ± 0.14 and 99.98 ± 0.22, respectively. The method can be successfully applied for routine analysis of the quantitative determination of MOM and OLO in a combined dose.

Multiple-component covalent organic frameworks for simultaneous extraction and determination of multitarget pollutants in sea foods

Persistent organic pollutants (POPs), such as perfluoroalkyl and polyfluoroalkyl substances (PFASs), polychlorinated biphenyls (PCBs), and bisphenols (BPs), have been raising global concerns due to their toxic effects on environment and human health. The monitoring of residues of POPs in seafood is crucial for assessing the accumulation of these contaminants in the study area and mitigating potential risks to human health. However, the diversity and complexity of POPs in seafood present significant challenges for their simultaneous detection. Here, a novel multi-component fluoro-functionalized covalent organic framework (OH-F-COF) was designed as SPE adsorbent for simultaneous extraction POPs. On this basis, the recognition and adsorption mechanisms were investigated by molecular simulation. Due to multiple interactions and large specific surface area, OH-F-COF displayed satisfactory coextraction performance for PFASs, PCBs, and BPs. Under optimized conditions, the OH-F-COF sorbent was employed in a strategy of simultaneous extraction and stepwise elution (SESE), in combination with HPLC−MS/MS and GC−MS method, to effectively determined POPs in seafood collected from coastal areas of China. The method obtained low detection limits for BPs (0.0037 −0.0089 ng/g), PFASs (0.0038 −0.0207 ng/g), and PCBs (0.2308 −0.2499 ng/g), respectively. This approach provided new research ideas for analyzing and controlling multitarget POPs in seafood. Environmental implicationsPersistent organic pollutants (POPs), such as perfluoroalkyl and polyfluoroalkyl substances (PFASs), polychlorinated biphenyls (PCBs), and bisphenols (BPs), have caused serious hazards to human health and ecosystems. Hence, there is a need to develop a quantitative method that can rapidly detect POPs in environmental and food samples. Herein, a novel multi-component fluorine-functionalized covalent organic skeletons (OH-F-COF) were prepared at room temperature, and served as adsorbent for POPs. The SESE-SPE strategy combined with chromatographic techniques was used to achieve a rapid detection of POPs in sea foods from the coastal provinces of China. This method provides a valuable tool for analyzing POPs in environmental and food samples.

A rapid solid-phase extraction purification combined with UPLC[sbnd]MS/MS used for simultaneous determination of eight tetracyclines and three metabolite in chicken and pork

A method for rapid detection and identification of 8 tetracyclines (TCs) and 3 metabolite residues in chicken and pork was established and verified by combining rapid solid-phase extraction (SPE) technology with ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLCMS/MS). After a sample was extracted, it was purified with a PRiME HLB cartridge, and the cartridge did not need to be activated, balanced, or eluted. The filtrate was dried under nitrogen, redissolved, and subsequently analyzed via UPLCMS/MS. The limits of detection for chicken and pork were 0.05–0.48 μg/kg and 0.05–0.52 μg/kg, respectively. The limits of quantification were 0.16–1.61 μg/kg and 0.16–1.75 μg/kg, respectively. The recoveries were 85.15%–107.50% and 84.21%–106.37%, respectively. The established method was suitable for qualitative and quantitative analyses of TCs and their metabolite residues in chicken and pork and has been used for the detection of TC in chicken and pork samples from local markets.

Simultaneous Quantification of Vancomycin, Linezolid and Voriconazole in Human Plasma by UHPLC–MS/MS: Application in Therapeutic Drug Monitoring

Abstract Objective Individual differences challenge the treatment of vancomycin, linezolid and voriconazole in severe infections. This study aimed to build a simple and economical method for simultaneous determination of the three antibiotics in human plasma by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS) and provided a reference for therapeutic drug monitoring (TDM) of infected patients. Methods The plasma samples were precipitated by acetonitrile and detected and separated on a shim-pack GIST C18 column following the gradient elution within 5 min. Mass quantification was performed on multiple reaction monitoring mode under positive electrospray ionization. Results The linear ranges of vancomycin, linezolid and voriconazole were 1.00–100.00, 0.10–15.00 and 0.10–20.00 μg·mL−1, respectively, with good linearity (R2 > 0.99). The accuracy and precision, matrix effect, extraction recovery and stability were validated, and the results all meet the acceptance criteria of China Food and Drug Administration (CFDA) guidelines. Conclusion The UHPLC–MS/MS method was established and validated for the simultaneous determination of vancomycin, linezolid and voriconazole in human plasma and successfully applied to routine TDM for individualized treatment.

Isolation, identification and quantification of flavonoids from the flowers of <i>Staphylea pinnata</i> L.

Introduction. Search for new plant species containing biologically active substances (hereinafter – BAS) is one of the leading tasks of pharmacognosy as a science. The search for flavonoid glycosides in plant raw materials is especially relevant, since they have anti-inflammatory, antioxidant, immunostimulating, as well as weak fungicidal and bacteriostatic action. Staphylea pinnata L. is an endemic plant of the Caucasus, cultivated not only in Georgia, but also in the Russian Federation in the Northern and Northwestern Caucasus. In foreign literature there are studies of antioxidant, antiproliferative and cytotoxic activity of leaf extracts of several species of S. pinnata L., as well as inhibitory activity of COX-1, COX-2 and LTB4 formation. Meanwhile, no serious Russian-language scientific studies on either the chemical composition or pharmacological action of generative organs of S. pinnata were found in the literature. This work is part of a comprehensive phytochemical study of S. pinnata. The aim of the work is to study the qualitative and quantitative composition of flavonoids in the studied object.Aim. To isolate, identify and quantify flavonoids in flowers and buds of Staphylea pinnata L.Materials and methods. Alcohol-water extracts from dried generative organs of the studied plant were used as analyzed solutions. Solutions were analyzed on a spectrophotometer SF-2000 (LLC "OKB Spectr", Russia) after sample preparation with aluminum chloride and on an HPLC Nexera-i LC-2040 (Shimadzu Corporation, Japan) equipped with a column and sample thermostat, degasser and autosampler using an individually selected elution gradient of the mobile phase (0.1 % orthophosphoric acid/acetonitrile solution). The primary data were processed using LabSolutions Single LC software (Shimadzu Corporation, Japan). Compounds from the flavonoid group were identified by retention times. Detection was carried out using a UV detector with an absorption wavelength of 365 ± 2 nm.Result and discussion. Alcohol-water extracts from flowers and buds of S. pinnata L. were obtained. Quantitative evaluation by spectrophotometry for flavonoid content was carried out. A gradient elution mode for HPLC was selected for simultaneous determination of 7 flavonoid glycosides. These chromatographic conditions allowed the identification and quantification of astragaline, cynaroside, cosmosiin, narcissin and rutin in flowers and buds of Staphylea pinnata L. Flavonoid glycosides: raponticin and kaempferol were not detected.Conclusion. Flavonoid glycosides were isolated from the generative organs of S. pinnata L., a technique for quantitative determination of flavonoid glycosides in alcohol-water extracts was developed, astragalin, cynaroside, cosmosiin, narcissin and rutin were detected and quantified.

Distinguishable Magnetic Reporter Coordination with Buoyancy-Magnetism Separation for Immobilization-Free Dual-Target Electrochemical Immunosensing.

Simultaneous sensitive and precise determination of multibiomarkers is of great significance for improving detection efficiency, reducing diagnosis and treatment expenses, and elevating survival rates. However, the development of simple and portable biosensors for simultaneous determination of multiplexed targets in biological fluids still faces challenges. Herein, a unique and versatile immobilization-free dual-target electrochemical biosensing platform, which combines distinguishable magnetic signal reporters with buoyancy-magnetism separation, was designed and constructed for simultaneous detection of carcinoembryonic (CEA) and α-fetoprotein (AFP) in intricate biological fluids. To construct such distinguishable magnetic signal reporters with signal transduction, amplification, and output, secondary antibodies of CEA and AFP were respectively functionalized on methylene blue (MB) and 6-(ferrocenyl)hexanethiol (FeC) modified Fe3O4@Au magnetic nanocomposites. Meanwhile, a multifunctional flotation probe with dual target recognition, capture, and isolation capability was prepared by conjugating primary antibodies (Ab1-CEA, Ab1-AFP) to hollow buoyant microspheres. The target antigens of CEA and AFP can trigger a flotation-mediated sandwich-type immunoreaction and capture a certain amount of the distinguishable magnetic signal reporter, which enables the conversion of the target CEA and AFP quantities to the signal of the potential-resolved MB and FeC. Thus, the MB and FeC currents of magnetically adsorbed distinguishable magnetic reporters can be used to determine the CEA and AFP targets simultaneously and precisely. Accordingly, the proposed strategy exhibited a delightful linear response for CEA and AFP in the range of 100 fg·mL-1-100 ng·mL-1 with detection limits of 33.34 and 17.02 fg·mL-1 (S/N = 3), respectively. Meanwhile, no significant nonspecific adsorption and cross-talk were observed. The biosensing platform has shown satisfactory performance in the determination of real clinical samples. More importantly, the proposed approach can be conveniently extended to universal detection just by simply substituting biorecognition events. Thus, this work opens up a new promising perspective for dual and even multiple targets and offers promising potential applications in clinical diagnosis.

Comparative Study of Gas and Liquid Chromatography Methods for the Determination of Underivatised Neutral and Acidic Cannabinoids and Cholesterol

The aim of our study was to develop a gas chromatographic method coupled with mass spectrometry (GC-MS) for the determination of underivatised neutral (CBDs-N) and acidic (CBDs-A) cannabinoids (CBDs) and cholesterol (Chol). Emphasis was also placed on comparing our original GC-MS method with the currently developed C18-high-performance liquid chromatography with photodiode detection (C18-HPLC-DAD). A combination of a long GC column, shallow temperature column programme, and mass-spectrometry was employed to avoid issues arising from the overlap between CBDs and Chol and background fluctuations. The pre-column procedure for CBDs and Chol in egg yolks consisted of hexane extractions, whereas the pre-column procedure for CBDs in non-animal samples involved methanol and hexane extractions. CBDs-A underwent decarboxylation to CBDs during GC-MS analyses, and pre-column extraction of the processed sample with NaOH solution allowed for CBD-A removal. No losses of CBDs-N were observed in the samples extracted with NaOH solution. GC-MS analyses of the samples before and after extraction with NaOH solution enabled the quantification of CBDs-A and CBDs-N. CBDs-A did not undergo decarboxylation to CBDs-N during C18-HPLC-DAD runs. The use of the C18-HPLC-DAD method allowed simultaneous determination of CBDs-N and CBDs-A. In comparison to the C18-HPLC-DAD method, our GC-MS technique offered improved sensitivity, precision, specificity, and satisfactory separation of underivatised CBDs and Chol from biological materials of endogenous species, especially in hemp and hen egg yolk. The scientific novelty of the present study is the application of the GC-MS method for quantifying underivatised CBDs-A, CBDs-N, and Chol in the samples of interest.

Transcriptomics and UHPLC-QQQ-MS analyses reveal the dysregulation of branched chain amino acids metabolism in renal fibrotic rats

The dysregulated levels of branched chain amino acids (BCAA) contribute to renal fibrosis in chronic kidney disease (CKD), yet specific analysis of BCAA contents and how they are regulated still remain unclear. It is therefore of great scientific interest to understand BCAA catabolism in CKD and develop a sensitive method for simultaneous determination of individual BCAA and their metabolites branched chain α-ketoacids (BCKA). In this work, the important role of BCAA metabolism that drives renal fibrosis in the process of CKD was first revealed by using transcriptomics. The key target genes controlling BCAA metabolism were then validated, that is, mRNA levels of BCKDHA and BCKDHB, the regulating rate-limiting enzymes during BCAA metabolism were abnormally reduced by quantitative PCR (qPCR), and a similar drop-off trend of protein expression of BCKDH, HIBCH and MCCC2 that are closely related to BCAA metabolism was also confirmed by western blotting. Furthermore, we established a novel strategy that simultaneously determines 6 individual BCAA and BCKA in serum and tissue. The method based on dansylhydrazine derivatization and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry (UHPLC-QQQ-MS) achieved to simultaneously determine the contents of BCAA and BCKA, which is efficient and stable. Compared with normal rats, levels of BCAA including leucine, isoleucine and valine in serum and kidney of CKD rats was decreased, while BCKA including α-ketoisocaproic acid, α-ketomethylvaleric acid and α-ketoisovaleric acid was increased. Together, these findings revealed the abnormality of BCAA metabolism in driving the course of kidney fibrosis and CKD. Our current study sheds new light on changes in BCAA metabolism during CKD, and may facilitate development of drugs to treat CKD and renal fibrosis.