Chromatography-triple Quadrupole Tandem Mass Spectrometry Research Articles

Triple-template surface imprinted magnetic polymers for wide-coverage extraction of steroid hormones from human serum.

In this study, novel triple-template magnetic nanospheres by surface imprinting, called triple-template magnetic molecularly imprinted polymers (tri-MMIPs), were prepared for the detection of steroid hormones in human serum. The polymers were constructed by Fe3O4 as support, estrone (E1), progesterone (PROG), and estradiol (E2) as triple templates, acrylic acid (AA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker. The resulting tri-MMIPs were further characterized and applied as sorbents in human serum pretreatment. Coupled with ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) profiling after derivatization, 15 steroids (E1, 6-ketoE1, 4-OHE1, 16α-OHE1, DHEA, 4-MeOE1, PROG, PREG, 17-OHPROG, 7-DHE2, E2, 2-OHE2, 16-epiE3, E3, 2-MeOE2) were successfully quantified. The developed method exhibited a good recovery (78.9-114%) and low limit of quantitation (LLOQ, 5-10pg/mL), which indicates a great potential for application in the analysis of multiple steroid hormones in complex biological samples.

Association of joint exposure to organophosphorus flame retardants and phthalate acid esters with gestational diabetes mellitus: a nested case-control study

BackgroundOrganic phosphate flame retardants (OPFRs) and phthalate acid esters (PAEs) are common endocrine-disrupting chemicals that cause metabolic disorders. This study aimed to assess the association between joint exposure to OPFRs and PAEs during early pregnancy in women with gestational diabetes mellitus (GDM).MethodsSeven OPFRs and five PAEs were detected in the urine of 65 GDM patients and 100 controls using gas chromatography-tandem triple quadrupole mass spectrometry (GC-MS). The association of OPFRs and PAEs with GDM was assessed using logistic regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) models.ResultsLevels of dibutyl phthalate (DBP), di-2-ethylhexyl phthalate (DEHP), diethyl phthalate (DEP), dimethyl phthalate (DMP), tris (2-butoxyethyl) phosphate (TBEP), tributyl phosphate (TBP), tris (2-chloroethyl) phosphate (TCEP), tris (1,3-dichloro-2-propyl) phosphate (TDCPP), tri-ortho-cresyl phosphate (TOCP), and triphenyl phosphate (TPHP) increased in the GDM group, and the OPFRs and PAEs, except for BBP and TMCP, were associated with GDM in the logistic regression analysis. In the WQS model, the mixture of OPFRs and PAEs was significantly positively associated with GDM (OR = 3.29, 95%CI = 1.27–8.51, P = 0.014), with TDCPP having the highest WQS index weight. BKMR analysis reinforced these results, showing that the overall association of joint exposure to the OPFRs and PAEs with GDM increased at exposure levels of the 55th to 75th percentiles. Independent exposure to TDCPP (OR = 1.42, 95%CI = 1.09–1.86, P = 0.011) and TBEP (OR = 1.29, 95%CI = 1.04–1.60, P = 0.023) were associated with an increased risk of GDM.ConclusionsEnvironmental exposure to OPFRs and PAEs is significantly associated with GDM. These findings provide evidence for the adverse effects of exposure to OPFRs and PAEs on the health of pregnant women.

Using sensory and instrumental analysis to assess the impact of grape smoke exposure on different red wine varietals in California

This study is an investigation of the impact of volatile phenols (VPs) released from burning wood during wildfires on grape composition and the resulting wines. Baseline levels of VPs in grapes and sensory differences between smoke-impacted wines and non-smoke-impacted wines were determined. The differences were related to different levels of smoke taint marker compounds in different wine matrices, using modified descriptive analysis (DA), multivariate statistics, gas chromatography mass spectrometry (GC-MS) and liquid chromatography-triple quadrupole tandem mass spectrometry (LC-QqQ-MS) of the free and total VPs, and individual bound glycosides, respectively. Across two DA panels, Cabernet Sauvignon, Cabernet Franc, Petite Verdot, Merlot, Syrah, Malbec, and Zinfandel wines made from grape originating from different areas in California were evaluated. The results show sensory differences between highly smoke-impacted and non-impacted wines with wines made from highly smoke-impacted grapes characterized as smoky, barbeque, medicinal, and having a retro-nasal ashtray character. Low smoke-impact wines based on free and total VP concentrations were not significantly different from the non-impacted wines when rated through descriptive analysis. The amount of smoke exposure was the largest contributor to smoke impact determined by sensory evaluation, but the different wine matrices from different locations and varietals also played an important role in determining the level of perceived smoke impact. The results of this study will contribute to our understanding of smoke impact and how it influences wine characteristics by relating smoke marker indicator compounds to wine sensory attributes.

Monosaccharide composition and glycosidic linkages analysis by ultra high performance liquid chromatography-triple quadrupole tandem mass spectrometry—Case study of plant polysaccharides

Monosaccharide composition and glycosidic linkages analysis are essential for the structural characterization and biological activity research of polysaccharides. To simplify the analysis steps and improve detection efficiency, this study developed monosaccharide compositions and glycosidic linkages detection methods based on UPLC-QqQ-MS/MS, and established a plant polysaccharide glycosidic linkages library. Furthermore, the detailed analysis process of monosaccharide compositions and glycosidic linkages was presented through a plant polysaccharide (Chinese bayberry wine polysaccharide, CPW) example. The results showed that the monosaccharide analysis method could identify and quantify 20 monosaccharides within 13 min by 6 chromatograms. By this method, 7 monosaccharides were detected in CPW, which was consistent with previous results obtained using ion chromatography. Meanwhile, the UPLC-QqQ-MS/MS based method could analyze 112 glycosidic linkages of 9 plant monosaccharides within 30 min, and the results were distributed on 11 chromatograms. According to the approach, 44 different glycosidic linkages were identified in CPW. Based on Congo red assay and molecular weight as well as our findings of monosaccharide composition and glycosidic linkages, we proposed that CPW may consist of two distinct sugar chains: One composed of 1–2,4-Rha, 1–3,4-GalA, and 1-F-Ara, and the other composed of 1–3,4-Gal, 1–4-Gal, 1–3,4,6-Gal, and 1-F-Ara.

Content and Health Risks of Microplastics and Phthalate Esters in Bottled Water

To study the content and health risks of microplastics （MPs） and phthalate esters （PAEs） in bottled water, a quantitative analysis of MPs was conducted by using Rose Bengal staining and stereomicroscopy. Seven PAEs were quantified by using gas chromatography-triple quadrupole tandem mass spectrometry （GC-MS/MS）. The daily intake of MPs was estimated and the carcinogenic and non-carcinogenic risks of PAEs were evaluated through a health risk assessment model. The results showed that the abundance of MPs in 21 bottled waters ranged from 48 n·L-1 to 216 n·L-1 （with the median abundance of 88 n·L-1）. The majority （72.1%） of MPs were fibrous in shape, and fragments accounted for only 27.9%. The average proportion of small-sized （10-50 μm） MPs was 33.9%, and that of large-sized MPs （>500 μm） was 4.3%. Most MPs were blue. The ∑(PAEs) in bottled water was 1.15-2.47 μg·L-1 （average 1.62 μg·L-1）. PAEs detected with high frequencies （100%） included dimethyl phthalate （DMP）, diethyl phthalate （DEP）, diisobutyl phthalate （DIBP）, di-n-butyl phthalate （DBP）, and di（2-ethylhexyl） phthalate （DEHP）, while the detection frequencies of butylbenzyl phthalate （BBP） and di-n-octyl phthalate （DNOP） were relatively low. The concentrations of DBP, DEHP, and DEP were all below the standard limits for drinking water in China. The ∑(PAEs) in the migration experiments was 0.61-2.04 μg·L-1 （average 1.33 μg·L-1）. The migration amounts of DBP and DEHP were also within the allowable range under the condition of 60℃ for 10 days. Seven PAEs were detected in both the bottles and caps, and the average content of DEHP in bottles was the highest, while DBP had the highest content in caps. The estimated intake of MPs （EDI） by drinking bottled water in different age groups of humans was 2.87 n·（kg·d）-1 for adults, 3.87 n·（kg·d）-1 for children, and 5.85 n·（kg·d）-1 for infants. The carcinogenic risks of DEHP in 21 bottled water samples and the migration test were less than the maximum acceptable risk level （1×10-6）, and the non-carcinogenic risk indices （HIs） of PAEs were all less than 1, indicating no non-carcinogenic risk to humans； however, the risk value of infants and children was higher than that of adults and should not be ignored.

Detection of PCBs and OCPs in the Irtysh River Water (GC-MS/MS) and ecological risk assessment

This study optimized a gas chromatography-tandem triple quadrupole mass spectrometry (GC-MS/MS) method for the determination of 21 persistent organic pollutants (POPs) in Irtysh River water, including 14 organochlorines (OCPs) and 7 polychlorinated biphenyls (PCBs). Factors such as column temperature ramping, selection of qualitative and quantitative ion pairs and collision energy were considered to achieve perfect separation and accurate quantification of all 21 target compounds. The limits of detection (LOD) for PCBs and OCPs ranged from 0.21 to 1.18 ng/L. Applying this method to detect POPs in the Irtysh River revealed concentrations of OCPs ranging from ND to 20.2 ng/L and PCBs from ND to 0.411 ng/L. Source analysis indicated that POPs in the Irtysh River mainly originate from historical industrial and agricultural activities, particularly the deliberate use of pesticides. To ensure ecological safety and human health, expanding the range of target analytes and monitoring periods is necessary. This study provides:•Qualitative and quantitative analysis methods for 7 PCBs and 14 OCPs.•Recoveries achieved ranged between 74.6 to 109 % with RSD less than 15 %.•Analysis of sources, transport pathways, accumulation status, and ecological risks of PCBs and OCPs in the Irtysh River.

Advanced technology based on Poly(deep eutectic solvent) core–shell nanomaterials enriched with Fructus Choerospondias phenols for efficient defense against UVB-induced ferroptosis

Plant phenolic compounds serve as significant natural antioxidants. However, traditional preparation methods face sustainability challenges. In this study, we synthesized a novel deep eutectic solvent (DES) modified core–shell nanomaterial composed of betaine, ethylene glycol and dopamine hydrochloride based on the spatial arrangement formed by the abundant weak interaction forces in the poly(deep eutectic solvent) (PDES). Utilizing the PDES magnetic nanomaterial and combined with ultrasound-assisted matrix solid phase dispersion (UA-MSPD), it was able to efficiently enrich Fructus Choerospondias phenols (FCP) up to 61.468 ± 0.405 mg/g. Density functional theory (DFT) was used to analyze the adsorption mechanism between the material and the target compounds, which involved weak interactions of electrostatics, hydrogen bonds, and π-π stacking, while maintaining the activity of phenols without destroying the molecular structure. Remarkably, the adsorption efficiency of the material remained above 80 % after six repetitions, indicating excellent reusability. FCPs were identified and analyzed using ultra-performance liquid chromatography-tandem triple quadrupole mass spectrometry (UPLC-Q-TOF-MS). The FCP prepared by Fe3O4@SiO2@PDES exhibited superior in vitro antioxidant performance, achieving enrichment and purification in one step. Cell experiment results showed that FCP could scavenge ROS, regulate cytokines, and reduce ferroptosis caused by ultraviolet radiation, making FCP have therapeutic value in practical applications. The technology opens up a new way for the green and sustainable production and enrichment of plant phenolic compounds for anti-aging treatment.

Evaluation of pharmacokinetic herb-drug interaction of diabecon and losartan by UHPLC-MS/MS

The diabecon is an ayurvedic herbal formulation that contains a mixture of herbs traditionally used as antidiabetic which is reported in the ayurvedic pharmacopeia of India and Indian Materia medica. The diabetic population has a common co-morbidity of hypertension for which losartan drug is commonly used for the treatment of hypertension. However, there is a lack of research on the pharmacokinetics interaction between diabecon and losartan. This research aims to investigate the influence of diabecon on the pharmacokinetics of losartan drugs in rats by establishing a highly sensitive ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry (UHPLC-MS/MS) method. The method was validated according to the USFDA guidelines and was applied for the pharmacokinetic study. The lowest concentration of losartan detection in rat plasma was found to be 1 ng/mL and the accuracy and precision were within the linear range (1–1500 ng/mL). The results revealed that after 28 days of dosing diabecon, it has altered the pharmacokinetic parameters like area under the curve (AUC0-t), drug clearance (Cl/F), and rate of elimination (Ke) of losartan, which may happen due to enzyme induction. Although there was a change in the pharmacokinetic parameters of losartan when administered in the presence of diabecon, it was found to be nonsignificant in rats (p > 0.05). According to the best of our knowledge, this is the first article that discusses the pharmacokinetic herb-drug interaction between diabecon and losartan.

The variation of acrylamide and 5-hydroxymethylfurfural in tea with different roasting degrees and the effects of tea polyphenols on their formation.

Roasting is an essential step in making roasted teas, and its role in producing flavors has been widely studied. However, the variation of potential hazardous compounds during the tea roasting process is still vague. The present study established an effective method based on liquid chromatography-triple quadrupole-tandem mass spectrometry to simultaneously determine the variation of acrylamide (AA), 5-hydroxymethylfurfural (5-HMF), and free amino acids during the tea roasting process. Meanwhile, the effects of several tea polyphenols on the formation of AA and 5-HMF were investigated by a wet-to-dry thermal model reaction. Medium-temperature roasted teas had the highest levels of AA and 5-HMF, with ranges of 0.13-0.15 μg g-1 and 68.72-123.98 μg g-1, respectively. Quantitative results showed that the levels of monosaccharides and amino acids decreased during roasting, which might contribute to the formation of 5-HMF and AA. Meanwhile, the decrease of epigallocatechin gallate (EGCG), epigallocatechin (EGC), and epicatechin (EC) might be related to their inhibitory effects on 5-HMF and AA. Thermal model reaction results showed that EGCG and EC significantly inhibited 5-HMF formation with a decline rate of 33.33% and 72.22%, respectively, mainly by trapping glucose. Gallic acid (GA) also had an inhibitory effect on the formation of AA (decreased by 92.86%) and 5-HMF (44.44%), mainly through impeding the preliminary reaction of asparagine and glucose. The roasting temperature determined the levels of AA and 5-HMF in teas. Catechins inhibited the formation of 5-HMF and AA mostly through trapping monosaccharides, while the inhibitory effect of GA was achieved by impeding the reaction. © 2024 Society of Chemical Industry.

Comprehensive Comparison of Three Different Medicinal Parts of Eupatorium lindleyanum DC. Using the RRLC-Q-TOF-MS-Based Metabolic Profile and In Vitro Anti-Inflammatory Activity.

Eupatorium lindleyanum DC. (EL) is a traditional Chinese herb known for its phlegm-reducing, cough-relieving and asthma-calming properties. It is widely used for treating cough and bronchitis. However, preliminary experiments have revealed wide variations in the composition of its different medicinal parts (flowers, leaves and stems), and the composition and efficacy of its different medicinal parts remain largely underexplored at present. In this study, non-targeted rapid resolution liquid chromatography coupled with a quadruple time-of-flight mass spectrometry (RRLC-Q-TOF-MS)-based metabolomics approach was developed to investigate the differences in the chemical composition of different medicinal parts of EL. We identified or tentatively identified 9 alkaloids, 11 flavonoids, 14 sesquiterpene lactones, 3 diterpenoids and 24 phenolic acids. In addition, heatmap visualization, quantitative analysis by high-performance liquid chromatography (HPLC-PDA) and ultra-high-performance liquid chromatography-triple quadrupole tandem mass spectrometry (UPLC-MS/MS) showed particularly high levels of sesquiterpene lactones, flavonoids and phenolic acids in the flowers, such as eupalinolide A and B and chlorogenic acid, among others. The leaves also contained some flavonoid sesquiterpene lactones and phenolic acids, while the stems were almost absent. The findings of in vitro activity studies indicated that the flowers exhibited a notable inhibitory effect on the release of the inflammatory factors TNF-α and IL-6, surpassing the anti-inflammatory efficacy observed in the leaves. Conversely, the stems demonstrated negligible anti-inflammatory activity. The variations in anti-inflammatory activity among the flowers, leaves and stems of EL can primarily be attributed to the presence of flavonoids, phenolic acids and sesquiterpene lactones in both the flowers and leaves. Additionally, the flowers contain a higher concentration of these active components compared to the leaves. These compounds mediate their anti-inflammatory effects through distinct biochemical pathways. The results of this study are anticipated to provide a scientific basis for the rational and effective utilization of EL resources.

Insight into the mechanism of adsorption and release of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol in sewage by modeling regional suspended particles for evaluation of the influence on monitoring of cannabis illicit abuse

The adsorption of 11-nor-9-carboxy-∆9-tetrahydrocannabinol (THC-COOH) by the suspended particles in sewage makes it fail to accurately monitor cannabis abuse. In this work, the model sewage sample was prepared through equivalent mixing the sewage from 10 different sewage treatment plants in Guangdong province of China and used as a comprehensive representative for investigating the adsorption and release behavior of THC-COOH on the suspended particles under different temperature and pH. The solid-liquid distribution of THC-COOH in sewage depended strongly on the adsorption and release properties which were susceptible to the temperature and pH, specially adjusting pH to 11.0 could release more than 90 % of THC-COOH from the suspended particles. By means of the kinetics models, pseudo-second-order kinetic and Weber-Morris models revealed the mechanism of adsorption and release of THC-COOH in sewage that was a relatively reversible and controllable process with multiple interactions, and then it was further confirmed by the validation experiment in a variety of actual sewage samples. According to the suggested pH, the modification of the existing detection protocol prior to high performance liquid chromatography-tandem triple quadrupole mass spectrometry (HPLC-TQ-MS/MS), was successfully applied to determination of THC-COOH in the stimulated positive samples, and the recoveries and RSDs were respectively 95.48–99.79 % and 4.0–5.6 %. The finding could greatly help improving the accuracy of not only the detection of THC-COOH in sewage but also the estimation data of the consumption level of cannabis in the related regions.

Discrimination of overheated pasteurized milk using mass spectrometry-based proteomics

Milk is one of the most widely consumed foods globally. To protect consumer interests, it is essential to establish an analytical method to detect the degree of heating in milk. A novel approach using nano liquid chromatography-orbitrap fusion mass spectrometer was developed for screening and identifing thermally sensitive peptides markers in the milk heating process (below 100 °C). This method integrates untargeted proteomics and chemometric tools to analyze protein quantitation data from differently heat-treated milk. Thirteen potential markers were screened out and identified, and further confirmed using by standard substances. Then, the accurate concentrations of 13 potential markers determined by isotope-dilution ultra-performance liquid chromatography-tandem triple quadrupole mass spectrometry were further mining the highly specific and thermally sensitive peptides markers. And Four peptides—INLFDTPLETQYVR, FELLGCELNGCTEPLGLK, QFQFIQVAGR, and GEADALNLDGGYIYTAGK—were selected as marker peptides to differentiate normal pasteurized milk from overheated pasteurized milk. The concentrations of INLFDTPLETQYVR ranges from 150 ± 11 µg/L to 350 ± 23 µg/L, while the concentrations of FELLGCELNGCTEPLGLK ranges from 40 ± 5 µg/L to 92 ± 3 µg/L, can distinguish normal pasteurized milk from overheated pasteurized milk. QFQFIQVAGR indicates overheated pasteurized milk at 230 ± 21 µg/L, and GEADALNLDGGYIYTAGK signifies 750 ± 43 µg/L. This study provides new insights for distinguishing overheated pasteurized milk.

A comprehensive study of Chuanwang Xiaoyan capsule based on characterization of chemical constituents in vitro and in vivo using ultra-high-performance liquid chromatography-quadrupole-Exactive Orbitrap mass spectrometry and pharmacokinetic study of multiple components in rats using ultra-high-performance liquid chromatography-triple quadrupole-tandem mass spectrometry.

Chuanwang Xiaoyan (CWXY) capsule is primarily used to treat a variety of acute and chronic inflammations, including acute and chronic pharyngitis and tonsillitis. However, a systematic study of its chemical constituents is still not available. This study evaluated the chemical constituents in vitro and metabolite profiles in vivo of CWXY using ultra-high-performance liquid chromatography (UHPLC) coupled with Q-Exactive Orbitrap mass spectrometry, and the pharmacokinetic behaviors of the nine main components in rats were detected using ultra-high-performance liquid chromatography-triple quadrupole-mass spectrometry (UPLC-QQQ-MS/MS). A total of 92 chemical constituents in CWXY were preliminarily identified in vitro. After oral administration to rats, 56 prototype components and 128 metabolites of CWXY were detected in the biological samples of rat plasma, urine, bile, and feces. Of these prototype components and metabolites, seven new compounds, namely M15, M16, M25, M30, M31, M71, and M128, were detected for the first time. The quantitation method of nine components in rat plasma was developed using a pharmacokinetic study. To the best of our knowledge, this study was the first to investigate the pharmacokinetic behavior of triumbelletin.

An integrated LC-MS/MS platform for noninvasive urinary nucleus acid adductomics: A pilot study for tobacco exposure

Tobacco smoke exposure significantly increases the level of global nucleoside damage. To evaluate all aspects of nucleic acid (NA) modifications, NA adductomics analyzes DNA, RNA and nucleobase adducts and provides comprehensive data. Liquid chromatography-tandem triple quadrupole mass spectrometry (LC-QQQ-MS/MS) and LC-Zeno-TOF-MS/MS were employed to screen for DNA, RNA and nucleobase adducts, as part of the analytical platform that was designed to combine high sensitivity and high resolution detection. We identified and distinguished urine nucleoside adducts via precursor ion and neutral loss scanning. A total of 245 potential adducts were detected, of which 28 were known adducts. The smoking group had significantly higher concentrations of nucleoside adducts in rat urine than the control group, based on MRM scanning, which was then used to perform relative quantitative analysis of these adducts. Urine nucleoside adducts were further confirmed using LC-Zeno-TOF-MS/MS. This highlights the potential of untargeted detection methods to provide comprehensive data on both known and unknown adducts. These approaches can be used to investigate the interactions among oxidative and alkylation stresses, and epigenetic modifications caused by exposure to tobacco smoke.

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.

Biosynthesis of Nanoparticles with Green Tea for Inhibition of β-Amyloid Fibrillation Coupled with Ligands Analysis.

Inhibition of amyloid β protein fragment (Aβ) aggregation is considered to be one of the most effective strategies for the treatment of Alzheimer's disease. (-)-Epigallocatechin-3-gallate (EGCG) has been found to be effective in this regard; however, owing to its low bioavailability, nanodelivery is recommended for practical applications. Compared to chemical reduction methods, biosynthesis avoids possible biotoxicity and cumbersome preparation processes. The interaction between EGCG and Aβ42 was simulated by molecular docking, and green tea-conjugated gold nanoparticles (GT-Au NPs) and EGCG-Au NPs were synthesized using EGCG-enriched green tea and EGCG solutions, respectively. Surface active molecules of the particles were identified and analyzed using various liquid chromatography-tandem triple quadrupole mass spectrometry methods. ThT fluorescence assay, circular dichroism, and TEM were used to investigate the effect of synthesized particles on the inhibition of Aβ42 aggregation. EGCG as well as apigenin, quercetin, baicalin, and glutathione were identified as capping ligands stabilized on the surface of GT-Au NPs. They more or less inhibited Aβ42 aggregation or promoted fibril disaggregation, with EGCG being the most effective, which bound to Aβ42 through hydrogen bonding, hydrophobic interactions, etc. resulting in 39.86% and 88.50% inhibition of aggregation and disaggregation effects, respectively. EGCG-Au NPs were not as effective as free EGCG, whereas multiple thiols and polyphenols in green tea accelerated and optimized heavy metal detoxification. The synthesized GT-Au NPs conferred the efficacy of diverse ligands to the particles, with inhibition of aggregation and disaggregation effects of 54.69% and 88.75%, respectively, while increasing the yield, enhancing water solubility, and decreasing cost. Biosynthesis of nanoparticles using green tea is a promising simple and economical drug-carrying approach to confer multiple pharmacophore molecules to Au NPs. This could be used to design new drug candidates to treat Alzheimer's disease.

Use of serum evaluation of contraceptive and ovarian hormones to assess reduced risk of pregnancy among women presenting for emergency contraception in a multicenter clinical trial

ObjectiveTo evaluate ovulation risk among women enrolling in an emergency contraception (EC) study by measuring contraceptive steroids and ovarian hormones. Study DesignWe used standard chemoluminescent assays to evaluate endogenous hormones [estradiol (E2), progesterone (P4), FSH, LH] and liquid chromatography-tandem triple quadrupole mass spectrometry (LC-MS/MS) to simultaneously analyze concentrations of ethinylestradiol (EE), dienogest (DNG), norelgestromin (NGMN), norethindrone (NET), gestodene (GSD), levonorgestrel (LNG), etonogestrel (ENG), segesterone acetate (NES), medroxyprogesterone acetate (MPA), and drospirenone (DRSP), in serum samples obtained at the time of enrollment in a recent study comparing oral ulipristal acetate and LNG EC in women with weight ≥ 80kg reporting no recent use of hormonal contraception. ResultsWe enrolled 532 and obtained a valid baseline blood sample from 520 women. Of these, 117 (22.5%) had detectable concentrations of a progestin [MPA (n=58, 11.2%), LNG (50, 9.6%), ENG (11, 2.1%), NET (5, 0.96%), NGMN (3, 0.06%), or DRSP (1, 0.02%)]. LNG was co-detected in all three participants with samples containing NGMN. Multiple progestins were detected in 8 other women: ENG/MPA (1); ENG/LNG (2); MPA/LNG (5). Samples from 55 (10.6%) had concentrations of one or more progestin considered above the minimum level for contraceptive [MPA ≥ 0.1ng/mL, n = 19; NGMN/LNG ≥ 0.2ng/mL, n = 31; ENG ≥ 0.09 ng/mL, n = 8; NET ≥ 0.35 ng/mL, n = 4]. We detected concentrations of serum P4 ≥ 3ng/mL, indicative of luteal phase (post-ovulation) status, in an additional 194 (37.3%) samples. ConclusionsMore than one third of enrolled in our clinical trial of oral emergency contraception had evidence of prior ovulation at the time of enrollment. Additionally, about 23% had evidence of recent use of hormonal contraception recent use of hormonal contraception. This results would have decreased the expected risk of pregnancy in the study. ImplicationsMany participants in a recent clinical trial of oral emergency contraception did not appear to be at risk for pregnancy or would not have benefited from intervention due to cycle timing. Investigators should consider the effects of these findings on expected pregnancy rates when determining sample size in future EC clinical trials, particularly when using non-inferiority designs or historical controls.Keywords

Development and validation of a GC-MS/MS method for the determination of iodoacetic acid in biological samples.

Iodoacetic acid (IAA) is a halogenated disinfection by-product of growing concern due to its high cytotoxicity, genotoxicity, endocrine disruptor effects, and potential carcinogenicity. However, the data on distribution and excretion of IAA after ingestion by mammals are still scarce. Here, we developed a reliable and validated method for detecting IAA in biological specimens (plasma, urine, feces, liver, kidney, and tissues) based on modified QuEChERS sample preparation combined with gas chromatography-tandem triple quadrupole mass spectrometry (GC-MS/MS). The detection method for IAA exhibited satisfactory recovery rates (62.6-108.0%) with low relative standard deviations (RSD < 12.3%) and a low detection limit for all biological matrices ranging from 0.007 to 0.032ng/g. The study showed that the proposed method was reliable and reproducible for analyzing IAA in biological specimens. It was successfully used to detect IAA levels in biological samples from rats given gavage administration. The results indicated that IAA was found in various tissues and organs, including plasma, thyroid, the liver, the kidney, the spleen, gastrointestinal tract, and others, 6h after exposure. This study provides the first data on the in vivo distribution inand excretion of IAA by mammals following oral exposure.

Detection of Extremely Low Level Ciguatoxins through Monitoring of Lithium Adduct Ions by Liquid Chromatography-Triple Quadrupole Tandem Mass Spectrometry.

Ciguatera poisoning (CP) is the most common type of marine biotoxin food poisoning worldwide, and it is caused by ciguatoxins (CTXs), thermostable polyether toxins produced by dinoflagellate Gambierdiscus and Fukuyoa spp. It is typically caused by the consumption of large fish high on the food chain that have accumulated CTXs in their flesh. CTXs in trace amounts are found in natural samples, and they mainly induce neurotoxic effects in consumers at concentrations as low as 0.2 µg/kg. The U.S. Food and Drug Administration has established CTX maximum permitted levels of 0.01 µg/kg for CTX1B and 0.1 µg/kg for C-CTX1 based on toxicological data. More than 20 variants of the CTX1B and CTX3C series have been identified, and the simultaneous detection of trace amounts of CTX analogs has recently been required. Previously published works using LC-MS/MS achieved the safety levels by monitoring the sodium adduct ions of CTXs ([M+Na]+ > [M+Na]+). In this study, we optimized a highly sensitive method for the detection of CTXs using the sodium or lithium adducts, [M+Na]+ or [M+Li]+, by adding alkali metals such as Na+ or Li+ to the mobile phase. This work demonstrates that CTXs can be successfully detected at the low concentrations recommended by the FDA with good chromatographic separation using LC-MS/MS. It also reports on the method's new analytical conditions and accuracy using [M+Li]+.

Simultaneous determination of seven artemisinin-related compounds in Artemisia annua by UPLC-QQQ-MS/MS

A variety of compounds in Artemisia annua were simultaneously determined to evaluate the quality of A. annua from multiple perspectives. A method based on ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry(UPLC-QQQ-MS/MS) was established for the simultaneous determination of seven compounds: amorpha-4,11-diene, artemisinic aldehyde, dihydroartemisinic acid, artemisinic acid, artemisinin B, artemisitene, and artemisinin, in A. annua. The content of the seven compounds in different tissues(roots, stems, leaves, and lateral branches) of A. annua were compared. The roots, stems, leaves, and lateral branches of four-month-old A. annua were collected and the content of seven artemisinin-related compounds in different tissues was determined. A multi-reaction monitoring(MRM) acquisition mode of UPLC-QQQ-MS/MS was used, with a positive ion mode of atmospheric pressure chemical ion source(APCI). Chromatographic separation was achieved on an Eclipse Plus RRHD C_(18) column(2.1 mm×50 mm, 1.8 μm). The gradient elution was performed with the mobile phase consisted of formic acid(0.1%)-ammonium formate(5 mmol·L~(-1))(A) and the methanol(B) gradient program of 0-8 min, 55%-100% B, 8-11 min, 100% B, and equilibrium for 3 min, the flow rate of 0.6 mL·min~(-1), the column temperature of 40 ℃, the injection volume of 5 μL, and the detection time of 8 min. Through methodological investigation, a method based on UPLC-QQQ-MS/MS was established for the simultaneous quantitative determination of seven representative compounds involved in the biosynthesis of artemisinin. The content of artemisinin in A. annua was higher than that of artemisinin B, and the content of artemisinin and dihydroartemisinic acid were high in all the tissues of A. annua. The content of the seven compounds varied considerably in different tissues, with the highest levels in the leaves and neither artemisinene nor artemisinic aldehyde was detected in the roots. In this study, a quantitative method based on UPLC-QQQ-MS/MS for the simultaneous determination of seven representative compounds involved in the biosynthesis of artemisinin was established, which was accurate, sensitive, and highly efficient, and can be used for determining the content of artemisinin-related compounds in A. annua, breeding new varieties, and controlling the quality of Chinese medicinal materials.