Altered intra- and inter-network brain functional connectivity associated with prolonged screen time in pre-school children with autism spectrum disorder.

Prolonged screen time (ST) has adverse effects on autistic characteristics and language development. However, the mechanisms underlying the effects of prolonged ST on the neurodevelopment of children with autism spectrum disorder (ASD) remain unclear. Neuroimaging technology may help to further explain the role of prolonged ST in individuals with ASD. This study included 164 cases, all cases were divided into low-dose ST exposure (LDE group 108 cases) and high-dose ST exposure (HDE group 56 cases) based on the average ST of all subjects. Spatial independent component analysis (ICA) was used to identify resting state networks (RSNs) and investigate intra- and inter-network alterations in ASD children with prolonged ST. We found that the total Childhood Autism Rating Scale (CARS) scores in the HDE group were significantly higher than those in the LDE group (36.2 ± 3.1 vs. 34.6 ± 3.9, p = 0.008). In addition, the developmental quotient (DQ) of hearing and language in the HDE group were significantly lower than those in the LDE group (31.5 ± 13.1 vs. 42.5 ± 18.5, p < 0.001). A total of 13 independent components (ICs) were identified. Between-group comparison revealed that the HDE group exhibited decreased functional connectivity (FC) in the left precuneus (PCUN) of the default mode network (DMN), the right middle temporal gyrus (MTG) of the executive control network (ECN), and the right median cingulate and paracingulate gyri (MCG) of the attention network (ATN), compared with the LDE group. Additionally, there was an increase in FC in the right orbital part of the middle frontal gyrus (ORBmid) of the salience network (SAN), compared with the LDE group. The inter-network analysis revealed increased FC between the visual network (VN) and basal ganglia (BG) and decreased FC between the sensorimotor network (SMN) and DMN, SMN and ATN, SMN and auditory network (AUN), and DMN and SAN in the HDE group, compared with the LDE group. There was a significant negative correlation between altered FC values in MTG and total CARS scores in subjects (r = - 0.18, p = 0.018).  Conclusion: ASD children with prolonged ST often exhibit lower DQ of language development and more severe autistic characteristics. The alteration of intra- and inter-network FC may be a key neuroimaging feature of the effect of prolonged ST on neurodevelopment in ASD children.  Clinical trial registration: ChiCTR2100051141. What is Known: • Prolonged ST has adverse effects on autistic characteristics and language development. • Neuroimaging technology may help to further explain the role of prolonged ST in ASD. What is New: • This is the first study to explore the impact of ST on intra- and inter-network FC in children with ASD. • ASD children with prolonged ST have atypical changes in intra- and inter-brain network FC.

Parent-child interaction related to brain functional alterations and development outcomes in autism spectrum disorder: A study based on resting state-fMRI.

BACKGROUND: Limited study has investigated the influence of parent-child interaction on brain functional alterations and development outcomes of autism spectrum disorder (ASD) children. This pilot study aimed to explore the relationship between parent-child interaction, brain functional activities and development outcomes of ASD children. METHODS: and Procedures: 653 ASD with an average age of 41.06 ± 10.88 months and 102 typically developmental (TD) children with an average age of 44.35 ± 18.39 months were enrolled in this study, of whom 155 ASD completed brain rs-fMRI scans. The amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) measured using resting-state functional magnetic resonance imaging (rs-fMRI) data reflect local brain function. The parent-child interaction was assessed by the Chinese Parent-child Interaction Scale (CPCIS). Childhood Autism Rating Scale (CARS) and developmental quotient (DQ) indicated development outcomes. OUTCOMES AND RESULTS: Total CPCIS score was negatively correlated with CARS total score, and positively correlated with DQ. The frequency of parent-child interaction was negatively correlated with ALFF values in the left median cingulate and paracingulate gyri (DCG.L) and ReHo values in the right superior frontal gyrus, medial (SFGmed.R)(P < 0.05, FDR correction). ALFF values in the DCG.L and ReHo values in the SFGmed.R play complete mediating roles in the relationship between parent-child interaction and performance DQ. CONCLUSION AND IMPLICATIONS: This study suggest that parent-child interaction has an impact on autistic characteristics and DQ of ASD children. Local brain regions with functional abnormalities in the DCG.L and SFGmed.R may be a crucial factors affecting the performance development of ASD children with reduced parent-child interaction.

Low-Temperature Cleanup Followed by Dispersive Solid-Phase Extraction for Determination of Nine Polar Plant Growth Regulators in Herbal Matrices Using Liquid Chromatography-Tandem Mass Spectrometry.

Polar plant growth regulators, used alone or doped in fertilizers, are most effective and widely utilized plant growth regulators (PGRs) in agriculture, which play important roles in mediating the yield and quality of crops and foodstuffs. The application scope has been extended to herbal medicines in the past 2 decades and relevant study is inadequate. The aim of this study is to establish a QuPPe-based extraction method containing low-temperature and d-SPE cleanup procedure followed by the detection on a selective multiresidue ultrahigh-performance liquid chromatography - triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS) in three herbal matrices. This simple, accurate, versatile and robust method was verified according to the validation criteria of the SANTE/12682/2019 guideline document. The analytical range was from 2.5 to 200 µg/L, and the average recoveries were in the range of 64.6-117.8% (n = 6). The optimized method was applied to 135 herbal medicines thereof. Result showed that the detection frequency of chlormequat was the highest in the investigated PGRs, with the positive rate of 15.6%. Improvement of the detection method for polar PGRs will enrich the coverage of PGRs, which is conducive to safeguard public health and ensure drug safety. Supplementary Information: The online version contains supplementary material available at 10.1007/s10337-023-04254-3.

Integrated Metabolome and Lipidome Strategy to Reveal the Action Pattern of Paclobutrazol, a Plant Growth Retardant, in Varying the Chemical Constituents of Platycodon Root.

Platycodon root, a medicinal food homology species which has been used in Asian countries for hundreds of years, is now widely cultivated in China. Treatment with paclobutrazol, a typical plant growth retardant, has raised uncertainties regarding the quality of Platycodon root, which have been rarely investigated. In the present study, metabolomic and lipidomic differences were revealed by ultra-high performance liquid chromatography coupled to ion mobility-quadrupole time of flight mass spectrometry (UPLC-IM-QTOF-MS). A significant decrease of platycodigenin-type saponins was observed in the paclobutrazol-treated sample. Carrying out a comprehensive quantitative analysis, the contents of total saponins and saccharides were determined to illustrate the mode of action of paclobutrazol on Platycodon root. This study demonstrated an exemplary research model in explaining how the exogenous matter influences the chemical properties of medicinal plants, and therefore might provide insights into the reasonable application of plant growth regulators.

COVID-19 and mental health disorders in children and adolescents (Review).

The new coronavirus has been present for two years and has had a widespread and sustained impact worldwide. There is growing evidence in the literature that COVID-19 may have negative effects on mental illness in patients and in healthy populations. The unprecedented changes brought about by COVID-19, such as social isolation, school closures, and family stress, negatively affect people's mental health, especially that of children and adolescents. The purpose of this paper is to review the literature and summarize the impact of COVID-19 disorders on children's and adolescents' mental health, the mechanisms and risk factors, screening tools, and intervention and prevention. We hope that the mental dysfunction caused by the pandemic will be mitigated through appropriate and timely prevention and intervention.

Multilaboratory Collaborative Study of a Nontarget Data Acquisition for Target Analysis (nDATA) Workflow Using Liquid Chromatography-High-Resolution Accurate Mass Spectrometry for Pesticide Screening in Fruits and Vegetables.

Nontarget data acquisition for target analysis (nDATA) workflows using liquid chromatography-high-resolution accurate mass (LC-HRAM) spectrometry, spectral screening software, and a compound database have generated interest because of their potential for screening of pesticides in foods. However, these procedures and particularly the instrument processing software need to be thoroughly evaluated before implementation in routine analysis. In this work, 25 laboratories participated in a collaborative study to evaluate an nDATA workflow on high moisture produce (apple, banana, broccoli, carrot, grape, lettuce, orange, potato, strawberry, and tomato). Samples were extracted in each laboratory by quick, easy, cheap, effective, rugged, and safe (QuEChERS), and data were acquired by ultrahigh-performance liquid chromatography (UHPLC) coupled to a high-resolution quadrupole Orbitrap (QOrbitrap) or quadrupole time-of-flight (QTOF) mass spectrometer operating in full-scan mass spectrometry (MS) data-independent tandem mass spectrometry (LC-FS MS/DIA MS/MS) acquisition mode. The nDATA workflow was evaluated using a restricted compound database with 51 pesticides and vendor processing software. Pesticide identifications were determined by retention time (tR, ±0.5 min relative to the reference retention times used in the compound database) and mass errors (δM) of the precursor (RTP, δM ≤ ±5 ppm) and product ions (RTPI, δM ≤ ±10 ppm). The elution profiles of all 51 pesticides were within ±0.5 min among 24 of the participating laboratories. Successful screening was determined by false positive and false negative rates of <5% in unfortified (pesticide-free) and fortified (10 and 100 µg/kg) produce matrices. Pesticide responses were dependent on the pesticide, matrix, and instrument. The false negative rates were 0.7 and 0.1% at 10 and 100 µg/kg, respectively, and the false positive rate was 1.1% from results of the participating LC-HRAM platforms. Further evaluation was achieved by providing produce samples spiked with pesticides at concentrations blinded to the laboratories. Twenty-two of the 25 laboratories were successful in identifying all fortified pesticides (0-7 pesticides ranging from 5 to 50 µg/kg) for each produce sample (99.7% detection rate). These studies provide convincing evidence that the nDATA comprehensive approach broadens the screening capabilities of pesticide analyses and provide a platform with the potential to be easily extended to a larger number of other chemical residues and contaminants in foods.

Plant metabolomics for studying the effect of two insecticides on comprehensive constituents of Lonicerae Japonicae Flos.

Pesticides' overuse and misuse have been reported to induce ingredient variations in herbal medicine, which is now gaining attention in the medicinal field as a form of alternative medicine. To date, available studies on pesticide-induced ingredient variations of herbal medicine are limited only on a few compounds and remain most others unexamined. In this study, a plant metabolomics-based strategy was performed to systematically explore the effects of two frequently used insecticides on the comprehensive constituents of Lonicerae Japonicae Flos (LJF), the flower buds of Lonicera japonica Thunb. Field trials were designed on a cultivating plot of L. japonica with controls and treatments of imidacloprid (IMI) and compound flonicamid and acetamiprid (CFA). Unbiased metabolite profiling was conducted by ultra-high performance liquid chromatography/quadrupole-Orbitrap mass spectrometer. After data pretreatment by automatic extraction and screening, a data matrix of metabolite features was submitted for statistical analyses. Consequently, 29 metabolic markers, including chlorogenic acids, iridoids and organic acid-glucosides were obtained and characterized. The relative quantitative assay was subsequently performed to monitor their variations across flowering developments. This is the first study that systematically explored the insecticide-induced metabolite variations of LJF while taking into account the inherent variability of flowering development. The results were beneficial for holistic quality assessment of LJF and significant for guiding scientific use of pesticides in the large-scale cultivation.

High performance liquid chromatography-tandem mass spectrometry method for residue determination of 39 plant growth regulators in root and rhizome Chinese herbs.

A simple, rapid, and effective method based on salting-out extraction and LC-MS/MS techniques was developed for the determination of 39 plant growth regulator (PGR) residues in two of the most common root and rhizome Chinese herbs, Codonopsis Radix (Dangshen) and Notoginseng Radix et Rhizoma (Sanqi). The extraction process was performed with acetonitrile-water (5:1) and citrate buffer extraction salt. The performance of the method was validated in accordance with the analytical quality control criteria of SANTE/11813/2017 guidelines. Analyte recoveries of 79.49-109.41% (Dangshen) and 80.17-102.81% (Sanqi) were achieved. The limit of quantifications (LOQs) were determined with the consideration of accuracy and precision. LOQs were lower than the lowest residue limits in EU pesticide regulation (10 µg/kg) for most PGRs. Moreover, the method was successfully applied in the analysis of 35 batches of Dangshen, and 60 batches of Sanqi products. The concentration of eleven PGRs were determined in analyzed samples.

An integrated approach for global profiling of multi-type constituents: Comprehensive chemical characterization of Lonicerae Japonicae Flos as a case study.

To fully capture the chemo-diversity of medicinal plants is very essential for understanding of their pharmacological activities and guiding scientific quality control. Aiming to facilitate chemical characterization and novel natural products discovery, the present study proposed an integrated approach based on two-dimensional liquid chromatography coupled with quadrupole-Orbitrap mass spectrometer (2D LC/Q-Orbitrap MS). An offline comprehensive two-dimensional (2D) LC system was constructed to cover and separate multi-type constituents by combining hydrophilic interaction chromatography (HILIC) and conventional reversed phase C18. A two-step mass defect filtering-induced exclusion list-data dependent acquisition was developed to increase MS/MS coverage and selectivity. Additionally, an efficient interpretation strategy, combining an automatic matching algorithm and molecular networking (MN), was introduced for rapid recognition of known compounds and efficient elucidation of unreported ones. As a case study, the integrated approach was tentatively applied for comprehensive characterization of complex multi-type components in Lonicerae Japonicae Flos (LJF), a traditional Chinese medicine. Consequently, a total of 537 compounds were characterized from LJF, including a large number of potential novel structures. It was demonstrated that the integrated approach is powerful in deep investigation on chemical diversity of medicinal plants and discovery of novel structures. Its application could also be extended for global profiling of other complicated chemical systems, such as Chinese medicinal formulas.

Qualitative screening and quantitative determination of 569 pesticide residues in honeysuckle using ultrahigh-performance liquid chromatography coupled to quadrupole-Orbitrap high resolution mass spectrometry.

A method for both qualitative screening and quantitative determination of 569 pesticides in honeysuckle was developed based on ultrahigh-performance liquid chromatography (UHPLC) coupled to quadrupole-Orbitrap high resolution mass spectrometry and an in-house executable compound database involving the theoretical masses of precursor and fragment ions and retention times. Different workflows were evaluated, validated and compared including Full MS-SIM, Full MS/ddMS2, Full MS/AIF and Full MS/DIA. For qualitative analysis, Full MS/DIA showed relatively low screening detection limits (SDLs) for most pesticides, but its MS2 identification seemed to be not reliable enough. Full MS/ddMS2 showed good repeatability of fragment ion recognition and less false positives. For quantitative analysis, the results of four workflows were comparable in terms of linearity and trueness, while Full MS-SIM and Full MS/ddMS2 gave better precision than the other two workflows for most pesticides at the spiking level of 0.01 mg/kg. Therefore, UHPLC-Full MS/ddMS2 was considered as the optimal workflow for both qualitative and quantitative analysis of honeysuckle samples. Pesticides were present in 75 of the 82 investigated samples, with concentrations ranging from 10.0 to 4116.9 µg/kg in some of the most severely contaminated samples.

Concurrent aquaporin-4-positive NMOSD and neurosyphilis: A case report.

Neuromyelitis optica spectrum disorder (NMOSD) is a common neuroinflammatory demyelinating disease associated with aquaporin-4 (AQP4) antibody in the central nervous system. Neurosyphilis is a neurological disease caused by Treponema pallidum infection. NMOSD commonly occurs concurrently with autoimmune diseases. However, they have rarely been associated with infectious diseases. In this report we describe a rare case of concurrent AQP4-positive NMOSD and neurosyphilis. A 60-year-old man was admitted to our hospital with a complaint of progressive weakness in his legs for one month. T2-weighted magnetic resonance images of the spinal cord showed longitudinal extensive lesions at C7-T7. The rapid plasma reagin test and T. pallidum particle agglutination assay performed using patient serum and cerebrospinal fluid (CSF) were positive. Additionally, the AQP4-immunoglobulin (Ig) G was detected in the serum and CSF. The patient's symptom gradually improved after penicillin and methylprednisolone treatment. This case report highlights the possibility of the presence of an infectious disease in patients with NMOSD.

Optimized QuEChERS Method Combined with UHPLC-MS/MS for the Simultaneous Determination of 15 Mycotoxins in Liquorice.

In our study, a reliable and rapid analytical method for the simultaneous determination of 15 mycotoxins (aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, alternariol, agroclavine, citrinin, diacetoxyscirpenol, deoxynivalenol, fumonisin B1, fumonisin B2, ochratoxin A, sterigmatocystin, T-2 toxin, and zearalenone) in liquorice using ultra-HPLC coupled to tandem MS was developed and validated. Due to the complex ingredients in liquorice, we chose a QuEChERS-based extraction procedure as the sample pretreatment. Meanwhile, for the first time, acetate buffer was used to replaced water, which can greatly reduce the concentration of formic acid in acetonitrile, which further reduces the extraction efficiency of impurities. The optimal combination of adsorbents is 150 mg primary secondary amine, 150 mg silica gel, 600 mg octadecylsilane, and 900 mg anhydrous magnesium sulfate. Electrospray ionization in both positive- and negative-ionization modes was applied to detect all the mycotoxins in a single run time of 15 min, with LOQs in the range of 0.125-2.5 µg/kg. The recoveries of determination obtained were in the range of 81.0-104.7%, whereas the analytes could be accurately quantified in the 0.25-625 µg/kg concentration range, with all coefficients being >0.992. Intra- and interday reproducibility were lower than 5.5 and 8.9%, respectively, for all analytical mycotoxins. The validated method was finally applied to screen mycotoxins in 31 batches of real samples collected from drugstores and hospitals in Shanghai, China. Our survey findings show that six mycotoxins were detected, including alternariol, citrinin, deoxynivalenol, fumonisin B1, ochratoxin, and zearalenone, and that the positive rate of mycotoxins was 54.8% in real samples, ranging from 3.37 to 520.6 µg/kg.

Multi-mycotoxins analysis in Pheretima using ultra-high-performance liquid chromatography tandem mass spectrometry based on a modified QuEChERS method.

A sensitive and high-throughput method was established and validated for the simultaneous determination of 22 mycotoxins in Pheretima aspergillum (E.Perrier) and Pheretima guillelmi (Michaelsen). A modified Quick Easy Cheap Effective Rugged and Safe (QuEChERS) method was used for sample preparation with recoveries ranging from 73% to 105% with relative standard deviations (RSDs) <8.0% for all target analytes. Ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-MS/MS) was applied for separation and detection in ESI (+) and ESI (-) modes with the limits of detection (LOD) in the range of 0.05-10µgkg-1. The 22 compounds could be accurately quantified in the 0.5-1000µgkg-1 concentration range with correlation coefficients >0.99. In all cases, the intra- and inter-day precisions were lower than 6% and 10%, respectively. Matrix-matched calibration was utilized for quantification purposes to compensate for the matrix effects. Furthermore, the established method was successfully applied in 17 batches of normal real samples collected from different areas of China and 2 batches of moldy samples due to improper storage, only mold-contaminated samples were confirmed to have fumonisin B1 (FB1) and fumonisin B2 (FB2) contamination at 2.54-3.78µgkg-1. The constructed method could serve as a practical application of the UHPLC-MS/MS method for the trace analysis of multiple mycotoxins in complex matrixes, especially for those with high lipid contents.

Multi-residue analysis of pesticides in traditional Chinese medicines using gas chromatography-negative chemical ionisation tandem mass spectrometry.

In this study, a residue analysis method for the simultaneous determination of 107 pesticides in traditional Chinese medicines (TCMs), Angelica sinensis, A. dahurica, Leonurus heterophyllus Sweet, Pogostemon cablin and Lonicera japonica Thunb., was developed using gas chromatography coupled with tandem mass spectrometry in negative chemical ionisation mode (GC-NCI-MS/MS). NCI has advantages of high sensitivity and selectivity to chemicals with electron-withdrawing groups, and yields low background interference. For sample preparation, QuEChERS (quick, easy, cheap, effective, rugged and safe) was applied. Due to the unique characteristics of TCMs, the clean-up step was optimised by adjusting amounts of primary secondary amine, C18, graphitised carbon black and silica sorbents. Validation was mainly performed by determining analyte recoveries at four different spiking concentrations of 10, 50, 100 and 200 ng g(-1), with seven replicates at each concentration. Method trueness, precision, linearity of calibration curves, lowest calibrated levels (LCLs) and matrix effects were determined to demonstrate method and instrument performance. Among the 107 pesticides tested, approximately 80% gave recoveries from 80% to 110% and < 10% relative standard deviation (RSD). The LCLs for nearly all pesticides were 5 ng g(-1), and as low as 0.1 ng g(-1) for dichlofenthion, endosulfan sulphate, flumetralin, isofenphos-methyl, methyl-pentachlorophenyl sulphide and trifluralin. The results indicate that GC-NCI-MS/MS is an excellent technique for quantitative and qualitative analysis of targeted GC-amenable pesticides at ultra-trace levels, especially in complex matrices such as TCMs.

[Determination of sulfur dioxide residues in sulfur fumigated Chinese herbs with headspace gas chromatography].

This paper aims to establish a method for the determination of sulfur dioxide in sulfur fumigation Chinese herbs. Sample powder and hydrochloric acid solution were isolated by paraffin layer in order to avoid early reactions, with the generation of sulfur dioxide, headspace with airtight needle was used to transfer sulfur dioxide into gas chromatograph, and detected with thermal conductivity detector. The analytical performance was demonstrated by the analysis of 12 herbs, spiked at four concentration levels. In general, the recoveries ranging from 70% to 110%, with relative standard deviations (RSDs) within 15%, were obtained. The limit of detection (LOD) was below 10 mg x kg(-1). Standard addition can be used for low recovery samples. The method is simple, less time-consuming, specific and sensitive. Methods comparison revealed that gas chromatography is better than traditional titration in terms of method operability, accuracy and specificity, showing good application value.

[Determination of seven toxaphene congeners in ginseng and milkvetch root by gas chromatography tandem mass spectrometry].

A novel method for the determination of representative toxaphene congeners in traditional Chinese herbal medicines was developed. Ginseng and Milkvetch Root were selected as the samples and seven toxaphene congeners were selected as the monitoring objects. The samples were extracted by accelerated solvent extraction with cyclohexane-acetone (9:1, v/v), then cleaned-up by Florisil solid phase extraction with hexane as the eluent and the residues were detected by gas chromatography-electron ionization tandem mass spectrometry (GC-EI-MS/MS) in multiple reaction monitoring (MRM) mode. The performance was demonstrated by the analysis of Ginseng and Milkvetch Root samples spiked with toxaphene congeners at three concentration levels of 0.005, 0.01 and 0.1 mg/kg. The recoveries ranged from 72.4% to 105% with the relative standard deviations (RSDs) of 0.96%-10.4%. The limits of detection (LODs) were 0.2-1.7 microg/kg. This method is sensitive and efficient in the aspect of extraction, and can be applied to monitor the residue of toxaphene congeners in Ginseng and Milkvetch Root.

Contrast-enhanced ultrasound diagnosis of splenic artery steal syndrome after orthotopic liver transplantation.

The aim of this study was to investigate the use of contrast-enhanced ultrasound (CEUS) for the detection of splenic artery steal syndrome (SASS) after orthotopic liver transplantation (OLT). Two hundred forty-seven patients underwent OLT. Blood tests and color Doppler flow imaging (CDFI) were performed at various time points after the operation. CEUS and celiac angiography were used for patients suspected of having SASS. If the diagnosis of SASS was confirmed, splenic artery embolization was performed to enhance hepatic artery flow. CEUS and angiography were performed for the assessment of postinterventional clinical outcomes. Three of the 247 patients died postoperatively, and 8 patients were suspected of having SASS because of elevated liver enzyme levels and slim or undetectable hepatic artery blood signals by CDFI at various points after the operation. In these 8 patients, CEUS showed a delayed and weak contrast-enhanced blood signal in the hepatic artery associated with a rapid and intense enhancement of the portal vein blood. No narrowing of the hyperintense signal was observed in the hepatic artery by CEUS. The 8 diagnoses of SASS were proven by celiac angiography, which showed delayed perfusion of the hepatic artery and rapid filling of the splenic artery. Immediately after the interventional procedure, CEUS demonstrated a significantly enlarged hyperintense blood signal in the hepatic artery. In conclusion, approximately 3.27% of SASS cases occur after OLT. SASS can be identified as a sluggish and weak hyperintense blood signal in the hepatic artery without the narrowing and interruption of the hypointense signal in CEUS imaging. CEUS is an effective imaging modality for the detection of SASS after OLT.

High throughput analysis of 150 pesticides in fruits and vegetables using QuEChERS and low-pressure gas chromatography-time-of-flight mass spectrometry.

A higher monitoring rate is highly desirable in the labs, but this goal is typically limited by sample throughput. In this study, we sought to assess the real-world applicability of fast, low-pressure GC-time-of-flight MS (LP-GC/TOFMS) for the identification and quantification of 150 pesticides in tomato, strawberry, potato, orange, and lettuce samples. Buffered and unbuffered versions of QuEChERS (which stands for "quick, easy, cheap, effective, rugged, and safe") using dispersive solid-phase extraction (d-SPE) and disposable pipette extraction (DPX) for clean-up were compared for sample preparation. For clean-up of all sample types, a combination of 150 mg MgSO4, 50mg primary secondary amine (PSA), 50 mg C18, and 7.5 mg graphitized carbon black (GCB) per mL extract was used. No significant differences were observed in the results between the different sample preparation versions. QuEChERS took < 10 min per individual sample, or < 1 h for two chemists to prepare 32 pre-homogenized samples, and using LP-GC/TOFMS, < 10 min run time and < 15 min cycle time allowed > 32 injections in 8 h. Overall, > 126 analytes gave recoveries (3 spiking levels) in the range of 70-120% with < 20% RSD. The results indicate that LP-GC/TOFMS for GC-amenable analytes matches UHPLC-MS/MS in terms of sample throughput and turnaround time for their routine, concurrent use in the analysis of a wide range of analytes in QuEChERS extracts to achieve reliable quantification and identification of pesticide residues in foods.

HPLC determination and MS confirmation of malachite green, gentian violet, and their leuco metabolite residues in channel catfish muscle.

Residues of malachite green (MG), gentian violet (GV), and their leuco metabolites in channel catfish muscle were individually determined by HPLC using diode array and fluorescence detectors and confirmed by tandem mass spectrometry. This detection scheme obviates a PbO(2) reactor that converts leuco forms to chromatic forms for absorbance detection, therefore eliminating uncertainties in oxidant depletion and data integrity. Extraction was performed once in pH 3 McIlvaine buffer and acetonitrile, followed by cleanup using a polymeric strong cation-exchange column. Liquid-liquid extraction was excluded to provide an environmentally responsible and relatively rapid protocol. Spectrometric limits of detection (LOD; S/N = 3) for MG (lambda = 620 nm) and GV (lambda = 588 nm) were 0.38 and 0.26 ng/g with 44.5-49.2% and 92.2-101.4% recoveries (1-10 ng/g, n = 6), respectively. Fluorometric LOD (S/N = 3) for LMG and LGV (lambda(ex) = 266 nm, lambda(em) = 360 nm) were 0.10 and 0.09 ng/g with 74.3-84.5% and 80.6-86.5% recoveries (1-10 ng/g, n = 6), respectively. This simplified protocol saves costs and meets the sensitivity requirements set by the Food and Drug Administration and the European Union.

[Simultaneous determination of 56 organochlorine and pyrethroid pesticides in traditional Chinese medicines by GC coupled with dual-tower and dual-column].

The paper is to report the establishment of a method for the determination of multi-residue organochlorine and pyrethroid pesticides in traditional Chinese medicines (TCMs). Fifty-six pesticides were extracted by high-speed homogenization, and then purified through gel permeation chromatography (GPC) and solid phase extraction (SPE) cartridges. The residues were simultaneously identified and quantified by GC-ECD equipped with dual tower, dual column and two micro-ECD detectors. The analytical performance was demonstrated by the analysis of 3 TCMs samples' extracts, spiked at three concentration levels for each pesticide. In general, the recoveries ranging from 70% to 110%, with relative standard deviations (RSDs) better than 15%, were obtained. The limit of detection (LOD) for most of the targeted pesticides tested was below 0.01 mg kg(-1). The method had good extraction efficiency, purification effect and good reproducibility, which could be applied to the determination of organochlorine and pyrethroid pesticide residues in the routine analysis of TCMs.