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Analysis of Pesticide Residues by Chromatographic Techniques Coupled with Mass Spectrometry
Published in José L. Tadeo, Analysis of Pesticides in Food and Environmental Samples, 2019
Wan Jing, Jin Maojun, Jae-Han Shim, A.M. Abd El-Aty
The triple quadrupole is a mass analyzer composed of three sets of quadrupoles. The first and third sets of quadrupoles are mass analyzers, and the middle set of quadrupoles is a collision activation chamber. It has several scanning modes, including product ion mode, precursor ion mode (also known as parent ion mode), neutral loss mode, and multiple reaction monitoring (MRM). The first three scanning modes are mainly used for the structural analysis of compounds by studying the fragmentation pathway of ions and the attribution of each ion. The MRM model is mainly used for quantitative analysis. It has better selectivity, stronger interference rejection ability, and a lower detection limit than the SIM model of the single quadrupole mass analyzer. The triple quadrupole mass spectrometer is commonly used in GC–MS/MS and LC–MS/MS. It is useful for the study of organic structure, and can also be used for the direct identification of mixed organics. It has a wide range of applications in pesticide multi-residue analysis.
Sensitive detection of antidiabetic compounds and one degradation product in wastewater samples by a new SPE-LC-MS/MS method
Published in Journal of Environmental Science and Health, Part A, 2021
Vasile-Ion Iancu, Roxana-Elena Scutariu, Florentina-Laura Chiriac, Gabriel-Lucian Radu
Formic acid was used in mobile phase to obtain good peak shape and for the production of the precursor ion [M + H]+. MS measurements were done in an 6410B triple quadrupole mass spectrometer. Ionization of compounds was performed using the next optimized settings: gas temperature 300 °C, capillary voltage, 3000 V, nitrogen nebulizer gas flow rate (10 L/min), nebulizer pressure 50 psi, the cell acceleration voltage (CAV) 4 V, collision energy 10-25 V, fragmentor voltage 80-120 V. Optimization of MS parameters involve the determination of the best ESI mode (positive or negative), collision energy, fragmenting voltage, and the best fragmentation pattern for each analyte. For higher sensitivity, product ions were monitored in the range of 80-120 V as fragmentor voltage. The two most intense product ions were selected for the analysis. Table 3 presents the optimized QQQ parameters for the determination of antidiabetic drugs in the environment samples. The adduct [M + H]+ was used as the precursor ion for MS determinations in the positive ionization mode. The first product ion as abundance was used for quantification and the second ion as abundance for confirmation. MS parameters were optimized by direct injection of individual calibration solution containing 5 mg/L of each compounds at a flow rate of 0.2 mL/min.
Characterization of inter-tissue and inter-strain variability of TCE glutathione conjugation metabolites DCVG, DCVC, and NAcDCVC in the mouse
Published in Journal of Toxicology and Environmental Health, Part A, 2018
Yu-Syuan Luo, Shinji Furuya, Weihsueh Chiu, Ivan Rusyn
Samples (10 μl) were automatically injected and chromatographed on a ZORBAX SSHD Eclipse Plus C18 column (3.0 x 50 mm, 1.8 μm, cat no. 959757–302; Agilent, Santa Clara, CA) with a guard column (2.1 x 5 mm, 1.8 μm, cat no.821725–901; Agilent) via a Waters Acquity H-class LC system (Waters, Milford, MA). Column temperature was maintained at 25°C. Initial chromatographic condition was maintained at 90% solvent A (water with 0.1% acetic acid, v/v) and 10% solvent B (methanol with 0.1% acetic acid, v/v) for 1 min, then increased to 90% solvent B by 3 min, then to 98% solvent B by 4 min, and then returned to initial condition until 7 min for sufficient equilibration prior to next run. Flow rate was set at 0.4 ml/min. All analyses were performed using Agilent 6740 triple-quadrupole mass spectrometer. The optimal MS/MS parameters were obtained via direct infusion of standards and isotopically-labeled internal standards in mobile phase at the flow rate of 0.5 ml/min (1:1 methanol:water, v/v, containing 0.1% formic acid). An Agilent Optimizer Tool (MassHunter, ver B.08.00) was utilized to finalize the optimal parameters of the fragmentor, collision energy, cell accelerator voltage and mass transition for each analyte (Table 1). Along with the real chromatographic condition, capillary voltage was optimal at 3500 V, sheath gas pressure and sheath gas temperature were optimal at 35 psi and 350°C, and gas temperature was optimal at 300°C (data not shown).
Anthraquinone of Pleurotus ostreatus as a bioactive and antimicrobial agent for finishing of textiles as a health care product
Published in The Journal of The Textile Institute, 2023
J. Bindhu, H. V Dharrunya, S. Charulatha, C. R. Sanjay, V. Dhanamurugan, S. Kavyha
Increased sensitivity and specificity will be allowed by a triple quadrupole mass spectrometer. The distillate was further analysed for volatile compounds using LCMS Stream select. The column is connected with UHPLC streams and a mass spectrometer. The UHPLC is of the C-18 column where fractions are injected. Water (A) and acetonitrile: isopropyl alcohol (B) in the ratio of 90:10 were the solvents used. The isocratic elution gradient system with 10% B solvent for 5 min, then 10-100% B over 20 min, and finally 100% B for 6 min was carried out. The ionization spectra were recorded in positive ionization mode between m/z 50 and 1200.