Triple Quadrupole Tandem Mass Spectrometry Research Articles

Simultaneous Determination of Levamisole, Mebendazole, and the Two Metabolite Residues of Mebendazole in Poultry Eggs by High-Performance Liquid Chromatography–Tandem Mass Spectrometry

The quantitative determination of levamisole (LMS), mebendazole (MBZ), and the two metabolites of MBZ, 5-hydroxymebendazole (HMBZ) and 2-amino-5-benzoylbenzimidazole (AMBZ), in poultry eggs (hen, duck, and goose) was achieved with high-performance liquid chromatography–tandem triple quadrupole mass spectrometry (HPLC–MS/MS). Samples were pretreated by liquid–liquid extraction and solid-phase extraction (LLE–SPE) to extract the target compounds, and an Oasis MCX SPE column was used for purification. Determination was performed on an Xbridge C18 column with 0.1% formic acid aqueous solution and acetonitrile as mobile phases. LMS, MBZ, HMBZ, and AMBZ were detected in a triple-quadrupole mass spectrometer with ESI in positive mode and quantified with an external standard. In blank eggs, the target analyte concentrations were within the limits of quantification (LOQs)—25 μg/kg (LMS) and 150 μg/kg (MBZ, HMBZ, and AMBZ)—and the matrix-matched calibration curves had good linearity (R2 ≥ 0.9990). In the same concentration range, the average recoveries of the target analytes were 85.98–97.38% (n = 6); the relative standard deviation (RSD), intraday RSD, and interday RSD ranged from 2.06 to 4.22%, 1.40 to 5.85%, and 2.34 to 6.32%, respectively. The limits of detection (LODs) ranged from 0.03 to 0.33 µg/kg, and the LOQs ranged from 0.08 to 1.00 µg/kg. Experimental verification showed that the HPLC–MS/MS method exhibited high specificity and sensitivity for quantitative analyses of egg samples. This study provides a rapid, efficient, and sensitive method for the simultaneous detection of LMS, MBZ, HMBZ, and AMBZ residues in foods of animal origin.

Stability of a calibrant as certified reference material for determination of trans-zearalenone by high performance liquid chromatography-diode array detection-triple quadrupole tandem mass spectrometry.

In this study, a trans-zearalenone (trans-ZEN) calibrant in acetonitrile as certified reference material (CRM) was prepared and intensively investigated the stability by high performance liquid chromatography coupled diode array detection and triple quadrupole tandem mass spectrometry (HPLC-DAD-MS/MS). The photoisomerization and degradation of main component and related impurities in trans-ZEN calibrant CRM was studied in detail under different light conditions such as UV light (254nm), sunlight, and visible light. Trans-ZEN in acetonitrile was confirmed a significant shift toward cis-ZEN up to a 52% cis-isomerization rate after exposing to UV light (254nm) in transparent ampule for 1day. The unsaturated double bond photosensitive groups of trans-ZEN and cis-ZEN will further undergo photoreaction to generate more isomers and related products with the increase of UV irradiation time. The calibrant in amber ampules was relatively stable after exposing to sunlight for 28days, with only 0.35% cis-isomer observed. The results indicated that trans-ZEN solution calibrant should be packed in amber ampules to avoid UV rays. Thermal stability test exhibited this calibrant was stable over 6weeks even at 60°C. Trans-ZEN was found to be more stable in acetonitrile than in methanol since an unknown impurity was observed in methanol after 6weeks placed at 25°C. The stability study of trans-ZEN calibrant provided a basis for the usage, storage, and transportation of the CRM. A concentration and expanded uncertainty of the trans-ZEN calibrant CRM of 11.01 ± 0.18µg/mL was developed.

Simultaneous determination of the four key fluoroquinolones and two antipsychotics in fish and shrimp by LC-MS/MS

In this study, we developed and validated a liquid chromatography triple quadrupole tandem mass spectrometry (LC-MS/MS) method used to simultaneously determine levels of four fluoroquinolones (ofloxacin, norfloxacin, lomefloxacin, and pefloxacin) and two antipsychotics (diazepam and methaqualone) in fish and shrimp. The samples were extracted with a mixture of anhydrous sodium sulfate and acetonitrile, and purified by C18 cartridge solid-phase extraction with an optimized eluent. The MS2 method was applied to recognize the molecular structure of these compounds according to a main fragmentation scheme. The key ions of identification and quantification were deduced from chemical structures. Multiple reaction monitoring was used to quantitatively analyse the compounds of interest. Satisfactory linearities were obtained (R 2 ≥0.99) with the limits of quantitation (LOQs) ranging between 0.03 and 1.96 μg kg−1. The recoveries were 74–122%, with a relative standard deviation (RSD) below 4.9% for these compounds at the spiking level of three, five, and ten times the LODs, respectively. The LC-MS/MS method allows precise and sensitive determination of residues of six important banned veterinary drugs in fish and shrimp tissue. This methodological approach solved the problem imposed by the need for two or more analysis methods to analyse the compounds of interest described in this study.

Antibacterial Activity of Chinese Red Propolis against Staphylococcus aureus and MRSA.

The antibacterial activity of propolis has long been of great interest, and the chemical composition of propolis is directly dependent on its source. We recently obtained a type of propolis from China with a red color. Firstly, the antibacterial properties of this unusual propolis were determined against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA). Studies on its composition identified and quantified 14 main polyphenols of Chinese red propolis extracts (RPE); quantification was carried out using liquid chromatography triple quadrupole tandem mass spectrometry (LC-QQQ-MS/MS) and RPE was found to be rich in pinobanksin, pinobanksin-3-acetate, and chrysin. In vitro investigations of its antibacterial activity revealed that its activity against S. aureus and MRSA is due to disruption of the cell wall and cell membrane, which then inhibits bacterial growth. Despite its similar antibacterial activities against S. aureus and MRSA, metabolomic analysis further revealed the effects of RPE on bacteria metabolism were different. The untargeted metabolomic results showed that a total of 7 metabolites in 12 metabolic pathways had significant changes (Fold change > 2, p < 0.05 *) after RPE treatment in S. aureus, while 11 metabolites in 9 metabolic pathways had significant changes (Fold change > 2, p < 0.05 *) after RPE treated on MRSA. Furthermore, RPE downregulated several specific genes related to bacterial biofilm formation, autolysis, cell wall synthesis, and bacterial virulence in MRSA. In conclusion, the data obtained indicate that RPE may be a promising therapeutic agent against S. aureus and MRSA.

Integrated LC-MS and GC-MS-Based Metabolomics Reveal the Effects of Plant Competition on the Rye Metabolome.

Plants compete with their neighbors about the limited resources available to them. Plants under induced stress resulting from competition may alter their metabolome to increase their resilience or enhance their defense mechanisms. In the present study, rye (Secale cereale) plants were cocultivated with different densities (3, 12, and 18 plants per pot) of Austrian pea (Pisum sativum subsp. arvense), hairy vetch (Vicia villosa), and Alexandrian clover (Trifolium alexandrinum L.) to elucidate the changes in the rye metabolome in response to the different levels of competition. Global metabolic profiling by liquid chromatography triple quadrupole tandem mass spectrometry (LC-QqQ-MS), liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS), and gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) was performed on rye plants, and the acquired data were analyzed using uni- and multivariate statistics. Targeted analysis showed that a high level of competition reduced the concentration of aglycone benzoxazinoids (BXs) and increased glycoside BXs in rye roots. Untargeted metabolomics analysis indicated an increase in the rye root content of the allelopathic compounds 4-hydroxybenzoic acid and uracil in response to competition. Untargeted analysis of rye shoots revealed that the plant competition increased the d-pyroglutamic acid, which is an elicitor of reactive oxygen species (ROS). Our results have enhanced the knowledge of the biochemical response of plant species to cocultivation.

Simultaneous quantification and evaluate the differences of two skeleton components in raw, salt and wine Angelicae Pubescentis Radix by UPLC-MS/MS in negative/positive modes coupled with chemometrics

The aim of this study was to establish an ultra-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry method with positive and negative ion exchange scanning mode for simultaneous quantification of two different skeleton components to reveal the differences among raw and processed Angelicae Pubescentis Radix . The results of methodology showed that each compound had good linearity and recovery rates. And the chemometrics results indicate that there were differences not only in Angelicae Pubescentis Radix samples from different sources but also in raw and processed Angelicae Pubescentis Radix . The results of this study confirm that the method has been successfully applied in simultaneous determination and discovering the difference of two different skeleton components between raw and processed Angelicae Pubescentis Radix for the first time. In short, the method could be an effective tool for detecting the quality of traditional Chinese medicine, and can better reveal the difference between raw and processed Chinese medicine from different sources.

A rapid and sensitive LC-MS/MS method for determination of the active component K6 in serum of patients with depression

Depression is a mental health disorder characterized by chronic negative mood, and depression has become a major threat to human health and quality of life. Anyupeibo capsule, a fifth-class new Chinese medicine, was prepared with extracts of Piper laetispicum C.DC. (Piperaceae), and the alkaloid K6 (5′-methoxy-3′,4′-methyl-enedioxycinnamic-acidisob-utylamide-isobutylamide) was found to be the main active component. Using high-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (LC-MS/MS), we developed a method to quantify the concentration of K6 in serum samples from patients with depression. Pretreatment of samples was completed based on solid-phase extraction, and the mobile phase for subsequent LC analysis consisted of aqueous ammonium acetate (0.1 mmol/L, phase A) and acetonitrile (phase B) with isocratic elution at 60% B. Chromatographic separation of K6 was achieved within 3 min with an Agilent ZORBAX SB-C18 column (2.1 × 150 mm, 3.5 µm) at a flow rate of 0.3 mL/min. A linear regression equation for K6 yielded correlation coefficients of r2 > 0.99 within a linear range 0.0503–100.5000 ng/mL. Extraction recovery ranged from 85.33% to 101.18%, and the matrix effect ranged from 87.15% to 100.28%. The inter-day and intra-day precision values—expressed as relative standard deviation—were less than 15%, and the corresponding accuracy values were within ±15%. All validation results for stability, specificity, and carry-over met the requirements of Pharmacopoeia. The LC-MS/MS method was applied to determine the K6 concentration in serum samples from patients with depression in a phase III clinical trial of Anyupeibo capsule.

Determination of 123 polycyclic aromatic hydrocarbons and their derivatives in atmospheric samples

Polycyclic aromatic hydrocarbons (PAHs) are a class of toxic organic pollutants. Until now, they have been detected in many regions and various environmental matrix. However, not all PAHs are usually detected by researchers, and no methods is established to analyze systematically hundreds of PAHs. In this study, 123 PAHs were identified and quantified using gas chromatography−tandem triple-quadrupole mass spectrometry (GC-MS/MS), which were divided into 3 groups: 32 regular PAHs (R-PAHs), 50 methyl-PAHs (Me-PAHs), 30 Nitro-PAHs (N-PAHs) and 11 hydroxyl-PAHs (OH-PAHs). The developed method was applied to detect the target PAHs in 6 marine gaseous samples and 6 particulate samples collected on board the research vessel Snow Dragon. Limits of detection (LOD) and limits of quantification (LOQ) were determined from 0.009 to 2.50 and 0.03–8.33 pg/m3, respectively. Recoveries of the internal standards in atmosphere were from 88% to 112%, 70%–104%, and 72%–102% for R-PAHs、Me-PAHs、N-PAHs and OH-PAHs, respectively, which showed the reliability of the experimental method. The total concentrations of 123 PAHs in marine air and particle samples were from 1532 to 7877 and 206–1022 pg/m3, respectively.

Simultaneous Determination of Vitamin D and Its Hydroxylated and Esterified Metabolites by Ultrahigh-Performance Supercritical Fluid Chromatography–Tandem Mass Spectrometry

In this study, an analytical method has been developed that, for the first time, allows simultaneous determination of vitamin D2 and vitamin D3 along with their hydroxylated and esterified forms. A group of 12 vitamin D analogues including vitamin D2 and vitamin D3, seven hydroxylated metabolites, and three ester forms were separated in a single 8.0 min run using ultrahigh-performance supercritical fluid chromatography coupled with triple quadrupole tandem mass spectrometry. Electrospray ionization and atmospheric pressure chemical ionization were investigated as ion sources, of which the latter showed a higher ionization efficiency. Chromatographic conditions were thoroughly evaluated by a step-by-step method, whereas an experimental design was applied for the optimization of the ionization parameters. Calibration and repeatability studies were carried out to validate the instrumental methodology showing determination coefficients higher than 0.9992 and good intra- and interday precision with relative standard deviations for areas and retention times lower than 10 and 2.1%, respectively, for all target analytes. Limits of quantification were below 3.03 μg/L for all compounds. The methodology was then validated and applied for the evaluation of human plasma samples in order to demonstrate its applicability to the analysis of vitamin D analogues in biological samples. Samples of five individuals were analyzed. Results show that linoleate-D3, vitamin D2, vitamin D3, 25-hydroxyvitamin D2, 24,25-dihydroxyvitamin D3, and 1,25-dihydroxyvitamin D3 could be detected in most samples, while the two latter also were quantified in all analyzed samples.

Comprehensive chemical profiling of the flowers of Citrus aurantium L. var. amara Engl. and uncovering the active ingredients of lipid lowering

The flowers of Citrus aurantium L. var. amara Engl. (FCAVA) is popularly consumed as an edible tea for anti-hyperlipidemia. But the active ingredients are not fully clear. In this study, ultra-high performance liquid chromatography coupled to quadrupole time of flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) with diagnostic product ions and neutral loss filtering strategy were successfully used for comprehensive characterization of chemical components in FCAVA. A total of 228 constituents, including 46 organic acids, 12 coumarins and 170 flavonoids, were tentatively characterized (30 confirmed with reference standards). Among them, nineteen flavonoids in 70 batches of FCAVA from different geographical origins were quantified by UHPLC tandem triple quadrupole mass spectrometry (QQQ-MS), which displayed satisfactory linearity, sensitivity, precision, accuracy, and stability. According to analytical results, the distribution of nineteen flavonoids in different geographical origins of FCAVA was clarified. In addition, the effect on LDL uptake of twenty-five flavonoids was investigated in HepG2 cell. It was found that the acacetin, diosmetin and rutin dose-dependently enhanced LDL uptake in HepG2 cells comparing to control. Furthermore, in a hyperlipidemia C57BL/6J mice model, administration of acacetin, diosmetin and rutin (30 mg/kg/d, intragastric, for three weeks) significantly decreased the levels of total cholesterol (TC), triglyceride (TG) and low density lipoprotein cholesterol (LDL-C) in plasma, respectively. Overall, these findings indicated the potential of FCAVA in the development of functional food or medicine for the prevention and treatment of hyperlipidemia, which could be considered for the improvement of quality standardization of FCAVA.

Fungal mycotoxins reduction by gamma irradiation in naturally contaminated sorghum

The objective of this study was the evaluation of the effects of different gamma irradiation doses on the survival of natural mycoflora as well as on the reduction of mycotoxin contamination (ochratoxin A [OTA] and aflatoxin B1 [AFB1]) in naturally contaminated sorghum samples. Mycotoxin levels were determined by ultra-high-performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS). The results have demonstrated that the dose of 3 kGy was sufficient to eliminate 90% of the natural fungal load of sorghum. Increasing gamma irradiation dose showed significant effects (p < .05) on initial mycotoxin content. At radiation dose of 10 kGy, maximum reduction of 59% and 32% were achieved in naturally contaminated sorghum for AFB1 and OTA, respectively. The obtained results clearly showed that gamma irradiation can be a promising method to control fungal and mycotoxin contamination in sorghum. Practical applications Sorghum is an important staple cereal crop intended for human foods and animal feeds worldwide. This study investigated the potential application of gamma irradiation to reduce fungal load and the mycotoxins (OTA and AFB1) in naturally contaminated sorghum. The results showed significant decrease in the natural fungal load. The amounts of OTA and AFB1 in sorghum were also reduced by applying this method. The results showed that gamma irradiation was a promising method to control fungal and mycotoxin contamination in sorghum within the permissible dose range applicable to food preservation (≤10 kGy).

Synthesis of superparamagnetic MnFe2O4/mSiO2 nanomaterial for degradation of perfluorooctanoic acid by activated persulfate.

In this paper, magnetic MnFe2O4/mSiO2 nanocomposites were successfully synthesized, and the activation performance of the materials for persulfate was evaluated by the degradation efficiency of perfluorooctanoic acid. The structure of the catalyst was proved to be a core-shell structure by several characterization methods. The mesoporous silicon coating can effectively avoid the agglomeration of MnFe2O4 and at the same time increase the contact area with the reactants. A comparison of different catalyst addition conditions demonstrates that MnFe2O4/mSiO2 can effectively activate the persulfate. The optimal reaction conditions were investigated by several key influencing factors. It was experimentally demonstrated that about 90% of PFOA (10mg·L-1) could be decomposed under the conditions of 0.4g·L-1 MnFe2O4/mSiO2 and PS, pH 5.68, and 25°C within 4h; the defluorination rate reached 58.33%. In addition, the cyclability and stability tests demonstrated that MnFe2O4/mSiO2 is a stable material that can be recycled. Furthermore, XPS characterization and radical scavenging experiments demonstrated that sulfate radicals (SO4·-) and hydroxyl radicals (OH) play a major role in the reaction of MnFe2O4/mSiO2 activated PS. Subsequently, the degradation products were detected by high-performance liquid chromatography tandem triple quadrupole mass spectrometry, indicating that the degradation of PFOA is a gradual process of defluorination and decarbonization in the presence of free radicals. Finally, the metal leaching rate is tested to prove that the material meets environmental requirements while reacting efficiently. In conclusion, this study shows that MnFe2O4/mSiO2 is an easily recoverable and highly efficient and stable material that has great potential for PS activation to treat organic pollutants in water.

Analytical Strategies for LC-MS-Based Untargeted and Targeted Metabolomics Approaches Reveal the Entomological Origins of Honey.

A comprehensive liquid chromatography-mass spectrometry (LC-MS)-based metabolomics approach was developed to discriminate honey harvested from Apis mellifera ligustica Spinola (A. mellifera) and Apis cerana cerana Fabricius (A. cerana). Based on an untargeted strategy, ultrahigh-performance liquid chromatography electrospray ionization quadrupole orbitrap high-resolution mass spectrometry (UPLC Q-Orbitrap) was combined with chemometrics techniques to screen and identify tentative markers from A. mellifera and A. cerana honey. In targeted metabolomics analysis, a sensitive method of solid-phase extraction followed by ultrahigh-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UPLC-MS/MS) was established for quantifying three markers, and the results showed that 3-amino-2-naphthoic acid and methyl indole-3-acetate could be considered markers of A. cerana honey, as they were present in higher amounts in A. cerana honey than in A. mellifera honey, whereas kynurenic acid was determined to be a marker of A. mellifera honey. This work highlights critical information for the authentication of A. cerana and A. mellifera honey.

Analysis of normal levels of free glycosaminoglycans in urine and plasma in adults

Plasma and urine glycosaminoglycans (GAGs) are long, linear sulfated polysaccharides that have been proposed as potential noninvasive biomarkers for several diseases. However, owing to the analytical complexity associated with the measurement of GAG concentration and disaccharide composition (the so-called GAGome), a reference study of the normal healthy GAGome is currently missing. Here, we prospectively enrolled 308 healthy adults and analyzed their free GAGomes in urine and plasma using a standardized ultra-high-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry method together with comprehensive demographic and blood chemistry biomarker data. Of 25 blood chemistry biomarkers, we mainly observed weak correlations between the free GAGome and creatinine in urine and hemoglobin or erythrocyte counts in plasma. We found a higher free GAGome concentration – but not a more diverse composition - in males. Partitioned by gender, we also established reference intervals for all detectable free GAGome features in urine and plasma. Finally, we carried out a transference analysis in healthy individuals from two distinct geographical sites, including data from the Lifelines Cohort Study, which validated the reference intervals in urine. Our study is the first large-scale determination of normal free GAGomes reference intervals in plasma and urine and represents a critical resource for future physiology and biomarker research.

Modifying current thin-film microextraction (TFME) solutions for analyzing prohibited substances: Evaluating new coatings using liquid chromatography

For identifying and quantifying prohibited substances, solid-phase microextraction (SPME) continues to arouse interest as a sample preparation method. However, the practical implementation of this method in routine laboratory testing is currently hindered by the limited number of coatings compatible with the ubiquitous high-performance liquid chromatography (HPLC) systems. Only octadecyl (C18) and polydimethylsiloxane/divinylbenzene ligands are currently marketed for this purpose. To address this situation, the present study evaluated 12 HPLC-compatible coatings, including several chemistries not currently used in this application. The stationary phases of SPME devices in the geometry of thin film-coated blades were prepared by applying silica particles bonded with various functional ligands (C18, octyl, phenyl-hexyl, 3-cyanopropyl, benzenesulfonic acid, and selected combinations of these), as well as unbonded silica, to a metal support. Most of these chemistries have not been previously used as microextraction coatings. The 48 most commonly misused substances were selected to assess the extraction efficacy of each coating, and eight desorption solvent compositions were used to optimize the desorption conditions. All samples were analyzed using an HPLC system coupled with triple quadrupole tandem mass spectrometry. This evaluation enables selection of the best-performing coatings for quantifying prohibited substances and investigates the relationship between extraction efficacy and the physicochemical characteristics of the analytes. Ultimately, using the most suitable coatings is essential for trace-level analysis of chemically diverse prohibited substances.

An integration strategy combined progressive multivariate statistics with anticoagulant activity evaluation for screening anticoagulant quality markers in Chinese patent medicine

Ethnopharmacological relevanceThe cardiovascular and cerebrovascular diseases affect human health globally. Naoxintong capsules (NXTs), a famous Chinese Patent Medicine, has been especially applied to treat cerebral infarction and coronary heart disease in clinical practice. The anticoagulant activity of this prescription plays an important role in this course of treatment. Aim of the studyThrombin and factor Xa (FXa) are two key targets considering the anticoagulant activity. The purpose of this investigation is to screen the quanlity markers as key thrombin and FXa inhibitors for the anticoagulant activity oriented quality control of Chinese patent medicine. Materials and methodsSimple multi-polar solvent extraction processes using various proportions of solvents were conducted and their thrombin/FXa inhibitory activities were evaluated in vitro. Bivariate correlation analysis (BCA), grey correlation analysis (GCA), and orthogonal partial least squares discriminate analysis (OPLS-DA) were adopted for screening the potential active markers related to the anticoagulant activity. The chemical structures of these active compounds were identified by UHPLC–Q-TOF-MS/MS and their thrombin/FXa inhibitory activity was determined. The molecular docking technology was applied to explore the interaction between the compounds and targets. The contribution of these anticoagulant active ingredients in NXT was also investigated. Last but not the least, the contents of these markers in NXT were determined by liquid chromatography-electrospray ionization tandem triple quadrupole mass spectrometry (HPLC-ESI-MS/MS) method. ResultsThe results showed that the NXT extract exhibited great activity against thrombin and FXa, especially extracted by 75% methanol (v/v). Six marker compounds with potential anticoagulant activity were screened out. Therein, four of the active compounds owing thrombin inhibitory activity (paeoniflorin, lithospermic acid, salvianolic acid B, Z-ligustilide) and five of the active compounds owing FXa inhibitory activity (3,5-dicaffeoylquinic acid, rosmarinic acid, lithospermic acid, salvianolic acid B and Z-ligustilide). In addition, these active compounds accounted for a large proportion of thrombin/FXa inhibitory activity of NXTs. The binding energy also showed the strong interaction formed by close connection of the compounds to the residues of targets. ConclusionsThe proposed integrated stategy could be an efficient strategy to screen potential thrombin/FXa inhibitors for the bioactivity related quanlity control of Chinese patent medicine.

Quantification of major milk proteins using ultra-performance liquid chromatography tandem triple quadrupole mass spectrometry and its application in milk authenticity analysis

An authenticity-based method was developed to detect economically motivated adulteration (EMA) in milk. To achieve this goal, 46 peptides released from trypsin digested milk proteins were identified and marker peptides were further selected based on their digestibility and stability characteristics to allow further quantifications of the milk proteins in the original samples using an isotope-dilution ultra-performance liquid chromatography tandem triple quadrupole mass spectrometry (UPLC-TQMS). Furthermore, to detect EMA in milk samples, 22 authentic milk powder samples were analyzed using the isotope-dilution UPLC-TQMS, and an authenticity threshold value --70.26 g/100 g as the content of all five major milk proteins to total protein—was established to evaluate milk samples with high adulteration risks. Finally, the threshold value was validated using soy protein adulterated milk samples. Results showed that the reported authenticity-based method was sensitive enough to detect the tampering of milk samples with as little as 10 % soy protein added. It is clear that this newly developed authenticity-based detection method is a powerful tool to detect unknown adulteration risks in milk samples. • Selected 5 marker peptides from 46 identified peptides based on their digestibility and stability characteristics. • Established and validated an isotope-dilution UPLC-TQMS method to quantitatively analyze major milk proteins. • Developed a milk authenticity threshold value to detect milk adulterations. • Validated the threshold value using artificially adulterated milk samples.

Pollution level, distribution characteristics and risk assessment of psychotropic substances and their metabolites in surface water of Lakes Gaoyou, Baoying and Shaobo, Jiangsu Province

为探究典型精神类药物及其代谢产物在高宝邵伯湖——宝应湖、高邮湖和邵伯湖表层水体的污染水平、分布特征及生态风险，利用超高效液相色谱-串联质谱法，对研究区域18个采样点位表层水体中3类（抗抑郁药物、抗癫痫药物和抗精神病药物）21种精神类药物及其代谢产物的浓度水平进行检测分析.结果表明，除奥卡西平外，其余20种典型精神类药物及代谢产物均有不同程度地检出，检出率范围为22.2%～100%，总检出浓度范围为1.4～224.5 ng/L.其中抗精神病药物利培酮检出浓度最高，浓度范围为0.1～64.1 ng/L.不同采样点精神类药物及其代谢产物的浓度存在空间差异，呈现邵伯湖和高邮湖南部浓度较高，高邮湖北部和宝应湖浓度较低的趋势.由聚类分析可知，点位S1、S7单独形成聚类，浓度分别为175.7和102.9 ng/L.对精神类药物及其代谢产物的来源分析发现，污水处理厂、生活污水和农业废水排放可能是高宝邵伯湖地表水中精神类药物及其代谢产物的主要来源.采用风险商值法（risk quotient，RQ）进行生态风险评估，结果表明高宝邵伯湖表层水体中卡马西平和环氧卡马西平对水生生物具有高风险（RQ>1）.精神类药物及其代谢产物在环境中持续性赋存的风险需引起重视.;To investigate the pollution level, distribution characteristic and ecological risk of psychotropic substances and their metabolites in Lakes Gaoyou, Baoying and Shaobo, Jiangsu Province, 18 water samples were collected. The concentrations of 21 psychotropic drugs and their metabolites in three classes:antidepressants, antiepileptics and antipsychotics were analyzed by ultra- high-performance liquid chromatography- triple quadrupole tandem mass spectrometry. The results indicated, in addition to oxcarbazepine, 20 typical drugs and their metabolites were detected at 18 sampling sites with the detection rates of 22.2%-100%, and the total concentration ranged from 1.4 to 224.5 ng/L. Among the detected substances, the concentration of risperidone (0.1-64.1 ng/L) was the highest. Spatial differences in the concentrations of psychotropic substances and their metabolites existed at different sampling sites, showing a trend of higher concentrations in Lake Shaobo and the southern part of Lake Gaoyou and lower concentrations in the northern part of Lakes Gaoyou and Baoying. The cluster analysis showed that point S1 and S7 formed separate clusters with concentrations of 175.7 ng/L and 102.9 ng/L, respectively. The source analysis found that wastewater treatment plants, domestic sewage and agriculture discharge may be the principal sources of the psychotropic substances and their metabolites. The risk quotient method showed that the RQ values for carbamazepine and oxcarbazepine were greater than 1 and were of high risk to aquatic organisms. The risk of psychotropic substances and their metabolites in the environment still needs attention.

The association between prenatal perfluoroalkyl substance exposure and symptoms of attention-deficit/hyperactivity disorder in 8-year-old children and the mediating role of thyroid hormones in the Hokkaido study.

Disruption of thyroid hormone (TH) levels during pregnancy contributes to attention deficit hyperactivity disorder (ADHD). Exposure to perfluoroalkyl substances (PFAS) during gestation may affect levels of maternal and neonatal TH; however, little is known about the effect of PFAS on ADHD mediated by TH. We investigated the impact of maternal PFAS exposure on children's ADHD symptoms with the mediating effect of TH. In a prospective birth cohort (the Hokkaido study), we included 770 mother-child pairs recruited between 2002 and 2005 for whom both prenatal maternal and cord blood samples were available. Eleven PFAS were measured in maternal serum obtained at 28-32weeks of gestation using ultra-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry. TH and thyroid antibody, including thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb) were measured in maternal blood during early pregnancy (median 11 gestational weeks) and in cord blood at birth. ADHD symptoms in the children at 8years of age were rated by their parents using the ADHD-Rating Scale (ADHD-RS). The cut-off value was set at the 80th percentile for each sex. Significant inverse associations were found between some PFAS in maternal serum and ADHD symptoms among first-born children. Assuming causality, we found only one significant association: maternal FT4 mediated 17.6% of the estimated effect of perfluoroundecanoic acid exposure on hyperactivity-impulsivity among first-born children. Higher PFAS levels in maternal serum during pregnancy were associated with lower risks of ADHD symptoms at 8years of age. The association was stronger among first-born children in relation to hyperactivity-impulsivity than with regard to inattention. There was little mediating role of TH during pregnancy in the association between maternal exposure to PFAS and reduced ADHD symptoms at 8years of age.

Quality Evaluation of Taxilli Herba from Different Hosts Based on Simultaneous Determination of Multiple Bioactive Constituents Combined with Multivariate Statistical Analysis.

Taxilli Herba (TAXH) is an important traditional Chinese medicine with a long history, dating from the Eastern Han Dynasty to the present times. However, the active constituents in it that parasitize different hosts vary, affecting its clinical efficacy. Given the complexity of the host origins, evaluating the quality of TAXH is critical to ensure the safety and effectiveness of clinical medication. In the present study, a quantitative method based on ultra-fast liquid chromatography tandem triple quadrupole mass spectrometry (UFLC-QTRAP-MS/MS) was established, which simultaneously determined the content of 33 active constituents, including 12 flavonoids, 4 organic acids, 12 amino acids, and 5 nucleosides in 45 samples. Orthogonal partial least squares discriminant analysis (OPLS-DA) was employed to classify and distinguish between TAXH and its adulterants, Tolypanthi Herba (TOLH). A hierarchical clustering analysis (HCA) was conducted combined with a heatmap to visually observe the distribution regularity of 33 constituents in each sample. Furthermore, gray relational analysis (GRA) was applied to evaluate the quality of samples to get the optimal host. The results demonstrated that TAXH excelled TOLH in quality as a whole. The quality of TAXH parasitizing Morus alba was also better, while those that were parasitic on Cinnamomum camphora and Glyptostrobus pensilis had relatively poor quality. This study may provide comprehensive information that is necessary for quality control and supply a scientific basis for further exploring the quality formation mechanism of TAXH.