Liquid Chromatography-triple Quadrupole Linear Ion Research Articles

Mushroom poisoning of Panaeolus subbalteatus from Ningxia, northwest China, with species identification and tryptamine detection

Mushroom poisoning is a significant contributor to foodborne disease outbreaks in China. This study focuses on two Panaeolus subbalteatus poisoning incidents accompanied by epidemiological investigations, species identification, and toxin detection in Ningxia, northwest China. In these two poisoning incidents, some patients exhibited gastrointestinal or neurological symptoms approximately 0.5 h after ingestion of a large amount of wild mushroom. Specifically, in Case 1, one of the three patients experienced nausea, vomiting, and numbness in the throat and limbs; in Case 2, one patient reported dizziness and an abnormal sense of direction. Through morphological and phylogenetic analyses, mushroom specimens were identified as P. subbalteatus. Psilocybin and psilocin were detected in mushroom samples, and only psilocin was detected in biological samples by liquid chromatography-triple quadrupole-linear ion trap mass spectrometry screening. The average psilocybin and psilocin contents in mushroom samples were 1532.2–1760.7 and 114.5–136.0 mg/kg (n = 3), respectively. Moreover, only psilocin was detected in blood and urine samples, with average concentrations 0.5–1.2 ng/mL (n = 3) and 2.5–3.1 ng/mL (n = 3), respectively. These findings provide technical support for managing similar incidents in the future.

Improved analysis of folpet and captan in foods using liquid chromatography-triple quadrupole linear ion trap mass spectrometry: applying mass filtering, collision, and trapping conditions

Accurate and highly sensitive analysis of folpet and captan was accomplished using liquid chromatography-triple quadrupole linear ion trap mass spectrometry (LC-QqQIT) with selective ion mode; mass filtering, collision, and trapping condition. Dimensional mass spectrometry (MS3) parameters were optimized for the residue detection of folpet and captan in six food commodities (apples, tomatoes, sweet pepper, wheat flour, sesame seeds, and fennel seeds). The sample preparation method was based on the known QuEChERS protocol, except a mixture of acetonitrile/acetone was used for the sample extraction from the sesame seeds. The robustness and reliability of the developed MS3 method were demonstrated by performing a full validation, according to SANTE/11312/2021, at 0.01-0.25mg/kg. Recovery ranged from 83 to 118% with a relative standard deviation below 19% in all the tested commodities, and limits of quantifications (LOQs) were 0.01mg/kg in apples and tomatoes; 0.03mg/kg in sweet pepper; and 0.05mg/kg in wheat flour, sesame seeds, and fennel seeds. Monitoring results showed that about 90% of apples contained captan residue, and in sweet pepper, concentrations of captan and folpet as high as 1.57 and 0.97mg/kg were found, respectively. The novel developed MS3 method enabled more reliable identification of these commonly problematic fungicides at lower LOQs than previously reported methods.

Systematic Qualitative and Quantitative Analyses of Wenxin Granule via Ultra-High Performance Liquid Chromatography Coupled with Ion Mobility Quadrupole Time-of-Flight Mass Spectrometry and Triple Quadrupole-Linear Ion Trap Mass Spectrometry.

Wenxin granule (WXG) is a popular traditional Chinese medicine (TCM) preparation for the treatment of arrhythmia disease. Potent analytical technologies are needed to elucidate its chemical composition and assess the quality differences among multibatch samples. In this work, both a multicomponent characterization and quantitative assay of WXG were conducted using two liquid chromatography–mass spectrometry (LC-MS) approaches. An ultra-high performance liquid chromatography–ion mobility quadrupole time-of-flight mass spectrometry (UHPLC/IM-QTOF-MS) approach combined with intelligent peak annotation workflows was developed to characterize the multicomponents of WXG. A hybrid scan approach enabling alternative data-independent and data-dependent acquisitions was established. We characterized 205 components, including 92 ginsenosides, 53 steroidal saponins, 14 alkaloids, and 46 others. Moreover, an optimized scheduled multiple reaction monitoring (sMRM) method was elaborated, targeting 24 compounds of WXG via ultra-high performance liquid chromatography–triple quadrupole linear ion trap mass spectrometry (UHPLC/QTrap-MS), which was validated based on its selectivity, precision, stability, repeatability, linearity, sensitivity, recovery, and matrix effect. By applying this method to 27 batches of WXG samples, the content variations of multiple markers from Notoginseng Radix et Rhizoma (21) and Codonopsis Radix (3) were depicted. Conclusively, we achieved the comprehensive multicomponent characterization and holistic quality assessment of WXG by targeting the non-volatile components.

An integrated strategy for the systematic chemical characterization of Salvianolate lyophilized injection using four scan modes based on the ultra-high performance liquid chromatography-triple quadrupole-linear ion trap mass spectrometry

Salvianolate lyophilized injection (SLI), a freeze-dried powder injection derived from aqueous extract of S. miltiorrhiza, is therapeutically used to treat the syndrome of blood stasis and collateral blockage during the recovery period after stroke. To date, it has remained a significant challenge to comprehensively characterize the compounds of SLI, particularly the minor components with potential bioactivities, in one sample injection analysis. Using an integrative four scan modes approach coupled with ultra-high performance liquid chromatography-triple quadrupole-linear ion trap mass spectrometry (UHPLC-QTRAP-MS/MS), we propose a novel, sensitive, and simple strategy for systematic and rapid profiling of the chemical components of SLI. First, an in-house database of constituents from the water-soluble extract of Danshen was created. Second, the fragmentation behaviors of the representative components in SLI were obtained using the untargeted scan mode enhanced MS (EMS)-information dependent acquisition (IDA)-enhanced product ion (EPI). The specific fragments acquired were then utilized to conduct precursor ion (Prec) and neutral loss (NL)-IDA-EPI scans. Following that, a sensitive predictive multiple reaction monitoring (pMRM)-IDA-EPI scan method with 454 transitions was developed based on the prominent fragment ions and plausible predictions. A total of 171 compounds were tentatively identified from SLI. Among them, 27 minor components have not been previously reported. This strategy allows most isomeric compounds at trace levels to be readily distinguished and annotated. Finally, 15 batches of 13 representative components in SLI selected by the qualitative results were accurately quantified. Salvianolic acid A (Sal A), Sal B, Sal D, lithospermic acid (LA), and rosmarinic acid (RA) were proved to be the predominant constituents. Sal B had the highest amount (195.08–350.46 μg·mg‐1), followed by LA, Sal A, Sal D, and RA. Moreover, these 15 batches of samples showed good uniformity, and no abnormal batches existed. These results suggest that this novel strategy can accelerate the identification of undiscovered chemical components and serve as an alternative method for in-depth profiling of compounds in other traditional Chinese medicines (TCMs).

Simultaneous Determination and Health Risk Assessment of Four High Detection Rate Pesticide Residues in Pu'er Tea from Yunnan, China.

Four pesticides with a high detection rate in Pu’er tea have been determined by a QuEChERS (quick, easy, cheap, effective, rugged, safe) method with multiwalled carbon nanotubes (MWCNTs), and combined ultrahigh-performance liquid chromatography–triple quadrupole linear ion trap-tandem mass spectrometry (UHPLC-QTRAP-MS/MS). MWCNs have been compared with other common purification materials, and found to be superior. The matrix effect was systematically studied, and the results show that the MWCNs can quickly and effectively reduce matrix interference values, which were in the range from −17.8 to 13.8. The coefficients (R2) were greater than 0.99, with the limit of quantification ranging from 0.1 to 0.5 μg/kg, and the recovery rate ranging from 74.8% to 105.0%, while the relative standard deviation (RSD) ranged from 3.9% to 6.6%. A total of 300 samples, taken from three areas in which Yunnan Pu’er tea was most commonly produced, tested for four pesticides. The results show that the detection rate of tolfenpyrad in Pu’er tea was 35.7%, which is higher than other pesticides, and the lowest was indoxacarb, with 5.2%. The residual concentrations of chlorpyrifos, triazophos, tolfenpyrad and indoxacarb ranged from 1.10 to 5.28, 0.014 to 0.103, 1.02 to 51.8, and 1.07 to 4.89 mg/kg, respectively. By comparing with China’s pesticide residue limits in tea (GB 2763-2021), the over standard rates of chlorpyrifos, tolfenpyrad, and indoxacarb were 4.35%, 0.87% and 0%, respectively. The risk assessment result obtained with the hazard quotient (HQ) method shows that the HQ of the four pesticides was far less than one, indicating that the risk is considered acceptable for the four pesticides in Pu’er tea. The largest HQ was found for tolfenpyrad, 0.0135, and the smallest was found for indoxacarb, 0.000757, but more attention should be paid to tolfenpyrad in daily diets in the future, because its detection rate, and residual and residual median were all relatively high.

Rapid and selective determination of 9 nitrosamines in biological samples using ultra-high performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry.

A sensitive, selective and convenient method for the simultaneous determination of 9 nitrosamines (NAs) in biological samples was developed using isotope dilution ultra-high performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry (UPLC-QTRAP-MS). Multiple reaction monitoring-information dependent acquisition-enhanced product ion (MRM-IDA-EPI) scan mode was performed to eliminate false positive results, and the whole detection procedure was characterized by less time consuming and simple sample preparation. 9 NAs were separated through a T3 column with the gradient elution of acetonitrile and water, and detected by UPLC-QTRAP-MS with an atmospheric pressure chemical ionization (APCI) source in the positive mode. The quantitative analysis was carried out via the isotope internal standard method with a matrix calibration curve. Under the optimized conditions, good linearity for the 9 NAs was achieved in the range of 0.2-20 μg L-1 with correlation coefficients (r) higher than ≥0.9991, and the limits of detection and limits of quantitation were 0.02-0.1 μg L-1 (S/N = 3) and 0.06-0.3 μg L-1 (S/N = 10), respectively. Satisfactory recoveries ranging from 79.4% to 108.0% were obtained, and the precision of the proposed method, indicated by the relative standard deviations (RSDs), was 2.3-12.9%. The matrix effect study showed that NDMA, NMOR and NMEA presented a matrix suppression effect, NDPHA displayed a matrix enhancement effect, and the matrix effects of the other 5 analytes could be ignored. Real application of the developed method in 13 urine and 24 plasma samples demonstrated that NDBA, NPIP and NPYR occurred in both urine and plasma samples with the concentration of 0.038-0.60 μg L-1, while other NAs were not detected. Such a method was sensitive and selective, and could be applied to the rapid qualitative and quantitative analysis of the 9 NAs in biological samples.

Chemical profiling and multicomponents quantitative analysis of Panzerina lanata by ultra-fast liquid chromatography with tandem mass spectrometry.

Panzerina lanata is a Chinese medicine with the bioactivity of detumescence and detoxification. In this study, novel qualitative and quantitative methods were established by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry and ultra-high-performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry, respectively. As a result, 20 compounds were identified or tentatively characterized including flavonoids, organic acids, alkaloids, and lignans, five of which were identified for the first time based on the reference standards. The quantitative approach exhibited good linearity (R2 >0.995), precision (RSDs<4.97%), stability (RSDs<4.77%), and recovery (96.04-104.14%). Afterward, this method was implemented to determine 11 flavonoids in four batches of P. lanata. Among them, seven compounds were quantified for the first time. Narcissin was abundant in each batch of P. lanata (average of 10.890-14.230mg/g) with the highest quantities. The results provide valuable information for quality evaluation.

Chemical profiling for bile acid derivatives in yak bile

Bile acids( BAs),the major constituents of bile,are also known to be potential biomarkers of various diseases,especially liver disease. The systematic analysis of BAs is believed to be of great importance towards the clarification of the effective material basis for bile-type medicines,and the diagnosis and therapy of related diseases as well. As a part of systematic study on bile-type medicine ongoing in our group,this study lays emphasis on the isomer discrimination,and the improvement of analytical method of BAs. Further,this method was subsequently applied to elucidate in depth the chemical profile of BAs in yak bile. Regarding isomer discrimination for BAs,we constructed relative response-collision energy curves( RRCECs) by high performance liquid chromatographyion trap-time of flight-mass spectrometry( HPLC-IT-TOF-MS) in combination with high performance liquid chromatography-triple quadrupole-linear ion trap mass spectrometry( HPLC-Qtrap-MS). As a result,both the optimum collision energy( OCE) and CE_(50) exhibited great correlations with structural characteristics,thus enabling the isomer distinguishing,such as unconjugated BAs,glycine-conjugated BAs,and taurine-conjugated BAs. According to information provided by mass spectrometry,the comparison of OCE and CE_(50),retention time matching,combined with reference substances and database retrieval,a total of 30 bile acid derivatives were observed and identified in yak bile. The newly developed method could serve as a feasible tool for the in-depth characterization of BAs in bile and biological samples.

A high efficient adsorbent for plant growth regulators based on ionic liquid and β-cyclodextrin functionalized magnetic graphene oxide

Four types of ionic liquids which composed of cation with imidazole ring and anion with benzene, naphthalene, anthraquinone and naphthoquinone ring were prepared and named VOIm+BenSO3-, VOIm+NapSO3-, VOIm+AQSO3- and VOIm+NQSO3-, respectively. Then, ionic liquids and β-cyclodextrin functionalized magnetic graphene oxide materials were firstly synthesized for the extraction of 23 plant growth regulators in vegetable samples. The synthesized materials anticipated the unique properties of ionic liquids, β-cyclodextrin, graphene oxide and Fe3O4@SiO2, including high surface area, high supramolecular recognition capability, superparamagnetism and large delocalized π-electron system, which were successfully characterized. Among four kinds of ionic liquids functionalized adsorbents, the VOIm+AQSO3- modified material exhibited high adsorption capability to 7 plant growth regulators compared with Fe3O4@SiO2/GO/β-CD, Fe3O4@SiO2/GO and other three types of ionic liquids based adsorbents. Parameters that could affect the recoveries of 7 plant growth regulators were investigated, such as mass ratio of Fe3O4@SiO2/GO/β-CD to ionic liquids, salt concentration, pH, amount of adsorbent, extraction time and desorption solvent. Under the optimal condition, the magnetic solid phase extraction method using VOIm+AQSO3- and β-cyclodextrin functionalized magnetic graphene oxide material (Fe3O4@SiO2/GO/β-CD/IL) as adsorbent was developed and coupled with ultra-high performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry for the determination of 7 plant growth regulators in vegetable samples. Validation results showed that the limit of detection and limit of quantitation were in the range of 0.01–0.18 μg/kg and 0.03–0.58 μg/kg, respectively. The satisfactory linearities were acquired in the concentration of 2–50 μg/kg with the correlation coefficients higher than 0.9982. Taken together, the synthesized Fe3O4@SiO2/GO/β-CD/IL was a highly effective magnetic solid phase extraction adsorbent for the enrichment of trace level of plant growth regulators in vegetable samples.

A targeted strategy to identify untargeted metabolites from in vitro to in vivo: Rapid and sensitive metabolites profiling of licorice in rats using ultra-high performance liquid chromatography coupled with triple quadrupole-linear ion trap mass spectrometry

It is challenging to conduct in vivo metabolic study for traditional Chinese medicines (TCMs) because of complex components, unpredictable metabolic pathways and low metabolite concentrations. Herein, we proposed a sensitive strategy to characterize TCM metabolites in vivo at an orally clinical dose using ultra-high performance liquid chromatography-triple quadrupole-linear ion trap mass spectrometry (UHPLC-QTRAP-MS). Firstly, the metabolism of individual compounds in rat liver microsomes was studied to obtain the metabolic pathways and fragmentation patterns. The untargeted metabolites in vitro were detected by multiple ion monitoring-enhanced product ion (EPI) and neutral loss-EPI scans. Subsequently, a sensitive multiple reaction monitoring-EPI method was developed according to the in vitro results and predicted metabolites to profile the in vivo metabolites. Licorice as a model herb was used to evaluate and validate our strategy. A clinical dose of licorice water extract was orally administered to rats, then a total of 45 metabolites in urine, 21 metabolites in feces and 35 metabolites in plasma were detected. Among them, 18 minor metabolites have not been reported previously and 6 minor metabolites were first detected in vivo. Several isomeric metabolites were well separated and differentiated in our strategy. These results suggested that this new strategy could be widely used for the detection and characterization of in vivo metabolites of TCMs.

Simultaneous determination of amantadine and rimantadine in feed by liquid chromatography-Qtrap mass spectrometry with information-dependent acquisition.

A sensitive method for simultaneous determination of amantadine and rimantadine in feed was developed using an ultra-high-performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry (UHPLC-Qtrap-MS) in the multiple reaction monitoring information-dependent acquisition-enhanced product ion (MRM-IDA-EPI) mode, and employing the mixed cation exchange (MCX) solid-phase extraction column as sample cleanup and amantadine-d15 and rimantadine-d4 as internal standards, respectively. Compared to traditional MRM mode, for the targeted drugs in feed simultaneously both the secondary mass spectra and MRM information can be obtainedusing UHPLC-Qtrap-MS with MRM-IDA-EPI mode, and thus more accurate qualitative confirmation results achievedeven at lower concentration of 0.2μg/L in acceptable purity fit values. After optimization of sample preparation, good linearities (R > 0.9994) were obtained over the concentration range from 1 to 200μg/L for amantadine and rimantadine. The precision was validated by intra-day and inter-day, and the relative standard deviations were all within 9.61%. Mean recoveries ranged from 76.1 to 112% at spiked concentrations of 0.5-100 μg/kg in three types of feed samples, including formula feed and complex concentrated feed for pigs and premix feed for chicken. The limits of detection (LODs) and quantification (LOQs) were 0.2 and 0.5μg/kg for both drugs, respectively. The application in real feed samples further proved the accuracy and reliability of the developed method. This method provides an important tool to detect illegal uses of amantadine and rimantadine in feed. Graphical abstract Simultaneous quantitation and qualitative confirmation of amantadine and rimantadine in feed by MRM-IDA-EPI.

Fabrication of a high selectivity magnetic solid phase extraction adsorbent based on β-cyclodextrin and application for recognition of plant growth regulators

An adsorbent, consisting of silica-coated Fe3O4 grafted graphene oxide and β-cyclodextrin (Fe3O4@SiO2/GO/β-CD), which possessed the merits of antioxidation, superparamagnetism, high surface area, high supramolecular recognition and environment friendly, was successfully fabricated. Considering the synergy between β-CD and graphene oxide in adsorption mechanism, the synthesized adsorbent could grasp compounds especially with aromatic structures through π-π interaction, hydrophobic interaction and host-guest inclusion complex forming. Based on the advantages, a magnetic solid phase extraction (MSPE) method for 9 PGRs using Fe3O4@SiO2/GO/β-CD as adsorbents was developed in this study. The characterizations of Fe3O4@SiO2/GO/β-CD were performed on Fourier transform infrared spectrometry (FT-IR), X-ray photoelectron spectroscopy (XPS), CHNS/O elemental analyzer, scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). Under the optimal MSPE condition, the Fe3O4@SiO2/GO/β-CD exhibited selectivity capability toward 9 PGRs when compared with Fe3O4@SiO2/GO. Meanwhile, the selectivity capability of Fe3O4@SiO2/GO/β-CD was higher than that of Fe3O4@SiO2/GO/α-CD except for 4-FPA. When the developed MSPE procedure was coupled with ultra-high performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry (UHPLC-QTrap-MS/MS) to quantitative analysis of 9 PGRs, linearities ranging from 2 to 50 μg/kg were achieved for 9 PGRs with the correlation coefficients (r2) in the range of 0.9975-0.9999. The limits of detection (LODs) for 9 analytes varied from 0.04 to 0.29 μg/kg. Finally, the proposed technique was applied to analyze PGRs residues in mutiple vegetable samples.

Stereoselective effects of ibuprofen on adult zebrafish brain tissues based on sphingolipidomics

The aim of this study was to investigate the stereoselective effects of a popular pharmaceutical and personal care product component ibuprofen (IBU) on adult zebrafish using sphingolipidomics. Sphingolipidomics is an effective method developed to determine sphingolipids present in biological samples using ultra-high performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry. Using this method, 46 sphingolipids in adult zebrafish brain samples were quantified after rac-/R-(-)-/S-(+)-IBU exposure, and the biomarkers were selected using chemometric approaches, including principal component analysis and orthogonal partial least squares discrimination analysis. Besides, combined with the results of the Duncan post hoc test and Dunnett post hoc comparison, sphingolipidomic perturbations were found to be induced after exposure to ibuprofen at environmental concentrations, and enantiomers of ibuprofen had stereoselective effects on zebrafish. This study may provide a new insight on the influence of ibuprofen on aquatic organisms.

Determination of 17 Plant Growth Regulator Residues by Ultra-High Performance Liquid Chromatography-Triple Quadrupole Linear Ion Trap Mass Spectrometry Based on Modified QuEChERS Method

A new method combining modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) with ultra-high performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry (UHPLC-QTrap-MS/MS) was developed for simultaneous determination of 17 plant growth regulator (PGR) residues in vegetables. Quantitative data acquisition was accomplished in multiple reaction monitoring (MRM) mode, and qualitative analysis and identification of target compounds was achieved by using linear ion trap scan functions. Qualitative and quantitative analysis can be simultaneously achieved by a pair of ions in UHPLC-QTrap-MS/MS. More importantly, QTrap system can minimize the risk of false positive and negative results. To achieve the optimum performance towards the target analytes, several parameters including the content of formic acid in mobile phase and scanning mode were investigated. In the optimized conditions, 17 PGRs showed good linearity over the range of 2~50 μg/L with correlation coefficients of 0.9902~0.9999. The limits of detections (LODs) were in the range of 0.01~1.32 μg/kg. The recoveries of 17 PGRs ranged from 78.5 to 119.2% with the spiked levels of 1, 2, and 5 μg/kg into homogenized radish, and the relative standard deviations (RSDs) ranged from 0.8 to 14.8%. The method illustrated is suitable for routine quantitative and qualitative analyses of PGRs in vegetable samples.

Rapid quantitative analysis of multi-components in Andrographis paniculata using UPLC-QqQLIT-MS/MS: Application to soil sodicity and organic farming

An ultra performance liquid chromatography-triple quadrupole-linear ion trap mass spectrometry method in multiple-reaction monitoring mode was developed for the rapid determination of 12 bioactive compounds in the leaf and stem of Andrographis paniculata (A. paniculata). Different soil conditions i.e., soil sodicity and use of organic manure was manually prepared and its effect on the extractive yield and quantity of bioactive phytoconstituents was studied. A good linear regression relationship (r2, 0.9988–0.9999), intra-day precision (RSD, 0.17–3.22%), inter-day precision (RSD, 0.31–3.44%), stability (RSD, 1.19–3.09%), and recovery (RSD, 1.03–3.20%) were obtained for all the analytes. The results showed significant differences in the content of diterpenoids, flavonoids, phenolics and triterpenoid compounds. Major markers i.e., andrographolide and neoandrographolide (187.5mg/g and 109.0mg/g, respectively) were detected highest in silty clay loam soil with addition of 3.5% organic manure in leaf of A. paniculata. This study was designed to benefit the cultivators by suggesting them about the suitability of soil and manure conditions to enhance the quantity of major bioactive compounds from A. paniculata. The present work described a highly specific, sensitive and rapid determination method of 12 bioactive compounds.

Cleaning Up Vegetable Samples Using a Modified “QuEChERS” Procedure for the Determination of 17 Plant Growth Regulator Residues by Ultra High Performance Liquid Chromatography–Triple Quadrupole Linear Ion Trap Mass Spectrometry

A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample pretreatment method coupled with ultra high performance liquid chromatography–triple quadrupole linear ion trap mass spectrometry (UHPLC-QTrap-MS/MS) was developed for simultaneous determination of 17 plant growth regulator (PGR) residues in vegetables. Generik ChlorF (GCF) was used as one of the adsorbents in modified QuEChERS procedure, which can selectively remove the chlorophyll of acetonitrile extract without causing the losses of PGRs that have planar structure. To achieve the optimum performance toward the target analytes, extraction solvent, the type of adsorbent, and the amount of the adsorbent were investigated. Under the optimized conditions, good linearities with correlation coefficients (γ) higher than 0.9954 were obtained. The new method provided sufficient sensitivity as reflected by the values of limit of detection (LOD) and limit of quantification (LOQ). The LOD varied between 0.01 and 0.70 μg/kg and the LOQ varied between 0.04 and 2.32 μg/kg. Acceptable recoveries ranging from 78.5 to 116.8 % with the relative standard deviations (RSDs) of 0.9–11.9 % were achieved. The evaluated method provided reliable screening, quantification, and identification of 17 PGRs in vegetables.

Unequivocal Enantiomeric Identification and Analysis of 10 Chiral Pesticides in Fruit and Vegetables by QuEChERS Method Combined With Liquid Chromatography-Quadruple/Linear Ion Trap Mass Spectrometry Determination.

In this research, 10 chiral pesticides in fruits and vegetables were simultaneously determined using chiral liquid chromatography triple quadrupole-linear ion trap hybrid mass spectrometry (LC-QqLIT). The QuEChERS method was applied for sample preparation, and an enhanced product ion (EPI) scan was used to acquire tandem mass spectrometry (MS/MS) spectra for the library search. Parameters including limit of detection (LOD), limit of quantification (LOQ), linearity, relative standard deviation (RSD), and matrix effects were evaluated in five representative matrices (strawberry, leek, cowpea, tomato, and eggplant). Good linearity with coefficient of determination (r(2) ) ≥0.997 was obtained for all 20 enantiomers in these five matrices over the range from 1.0 to 250 µg L(-1) . All the recoveries at 5 and 50 µg kg(-1) (n = 5) ranged between 70% and 120% with RSD below 20%, indicating satisfactory precision. The LOQ for the enantiomers ranged between 0.05 and 1 µg kg(-1) . Based on the proposed method, 135 commonly consumed fruits and vegetables taken from markets in Guizhou province, China, were analyzed. Enantioselective degradation for the selected chiral pesticides was observed in most of the positive samples.

Dynamic variation of bioactive compounds and aflatoxins in contaminated Radix Astragali during extraction process.

Although increasing attention has been paid to the health threat caused by mycotoxins in commodities such as food or medicines, mycotoxin transfer processes from crude material to products have raised little concern so far. Radix Astragali is a commonly used edible and medicinal herbal plant that is susceptible to contamination with aflatoxins from Aspergillus flavus. There have been no studies on mycotoxin transfer into pharmaceutical preparations or derivative products. To facilitate the aflatoxin reduction and bioactivity retention, the dynamic variations of aflatoxins as well as herbal compounds, namely calycosin-7-glucoside, astragaloside and formononetin, in Radix Astragali contaminated by A. flavus during water decoction and ethanol refluxing treatments were evaluated simultaneously by an ultra-fast liquid chromatography-triple quadrupole linear ion trap mass spectrometry method. After the extraction processes, although the amount of alfatoxins was reduced remarkably, aflatoxin residuals in preparation still exceed recommended limits, manifesting the great need to establish a limit for aflatoxins in herbal extractions or derivative products. Meanwhile, due to the hydrolysis of glucoside, water decoction period should be no longer than 4 h. This investigation would benefit from the determination of the dynamic variation of aflatoxins in infected herbs in preparation treatments, in order to further develop aflatoxin limits in herbal preparations.

Rapid screening and confirmation of 205 pesticide residues in rice by QuEChERS and liquid chromatography-mass spectrometry

A method for rapid screening and confirmation of 205 pesticide residues in rice was developed by combining QuEChERS and high performance liquid chromatography-triple quadrupole-linear ion trap mass spectrometry (LC-Q-TRAP/MS). The rice samples were extracted with acetonitrile, and then cleaned up with primary secondary amine (PSA), anhydrous magnesium sulfate (MgSO4) and C18 adsorbent. Finally, the samples were detected by LC-Q-TRAP/MS in multiple reaction monitoring with information-dependent acquisition of enhanced product ion (MRM-IDA-EPI) mode followed with database searching. A total of 205 pesticide residues were confirmed by retention times, ion pairs and the database searching using EPI library, and quantified by external standard method. All the pesticides showed good linearities with linear correlation coefficients all above 0.995. The limits of quantification (LOQs) for the 205 pesticides were 0.5-10.0 μg/kg. The average recoveries of the 205 pesticides ranged from 62.4% to 127.1% with the relative standard deviations (RSDs) of 1.0% - 20.0% at spiked levels of 10 μg/kg and 50 μg/kg, and only 20 min were needed for the analysis of an actual rice sample. In brief, the method is fast, accurate and highly sensitive, and is suitable for the screening and confirmation of pesticide residues in rice.

Rapid identification and quantification of five major mogrosides in Siraitia grosvenorii (Luo-Han-Guo) by high performance liquid chromatography–triple quadrupole linear ion trap tandem mass spectrometry combined with microwave-assisted extraction

An effective and rapid method involving high performance liquid chromatography–triple quadrupole linear ion trap tandem mass spectrometry (HPLC–QTrap–MS/MS) was developed for identification and quantification of five major mogrosides (mogroside III, mogroside IV, siamenoside I, mogroside V and 11-oxomogroside V) contained in real samples of Siraitia grosvenorii (Luo-Han-Guo) for the first time. High extraction efficiency was obtained for the five mogrosides by using microwave-assisted extraction compared with other common extraction methods during sample pretreatment prior to determination. Mass measurement for molecular ions and characteristic fragment ions well accorded with corresponding identification criteria. Quantitative data acquisition was accomplished in multiple reaction monitoring (MRM) mode, and further identification of target compounds was achieved by using ultra performance liquid chromatography–quadrupole-time-of-flightmass spectrometry. The proposed method could be used as a rapid and reliable approach for effective assessment of Luo-Han-Guo, and also provided use for reference in terms of real analysis of other traditional Chinese medicines in the future.