Characterization of drug interferences caused by coelution of substances in gas chromatography/mass spectrometry confirmation of targeted drugs in full-scan and selected-ion monitoring modes

1994 ◽  
Vol 40 (2) ◽  
pp. 216-220 ◽  
Author(s):  
A H Wu ◽  
D Ostheimer ◽  
M Cremese ◽  
E Forte ◽  
D Hill
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography Mass Spectrometry ◽  
Spectrometric Analysis ◽  
Targeted Drugs ◽  
Selected Ion Monitoring ◽  
Internal Standards ◽  
Target Drug ◽  
Full Scan ◽  
Chromatographic Mass

Abstract Interference by substances coeluting with targeted drugs is a general problem for gas chromatographic/mass spectrometric analysis of urine. To characterize these interferences, we examined human urine samples containing benzoylecgonine and fluconazole, and other drug combinations including deuterated internal standards that coelute (ISd,c) with target drugs, by selected-ion monitoring (SIM) and full-scan mass spectrometry. We show that, by SIM analysis, detecting the presence of an interferent is dependent on the specific IS used for the assay. When an ISd,c is used, the presence of another coeluting substance (interferent) suggests that the intensity of IS ions is substantially diminished, because the interferent affects both the ISd,c and target drug. When a noncoeluting IS (ISnc) is used, the interferent cannot be discerned unless it coincidently contains one or more of the ions monitored for either the target drug or ISnc. Under full-scan analysis, a coeluting interferent is directly discernable by examining the total ion gas chromatogram.

Gas Chromatographic/Mass Spectrometric Determination of α-Methylstyrene in Styrene-Based Polymers and Food Simulants

1991 ◽  
Vol 74 (5) ◽  
pp. 815-818
Author(s):  
Shigeru Tan ◽  
Takashi Tatsuno ◽  
Taro Okada
Keyword(s):  
Mass Spectrometry ◽  
Direct Injection ◽  
Mass Spectrometric ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Monitoring Method ◽  
Food Simulants ◽  
Multiple Ion Monitoring ◽  
Chromatographic Mass

Abstract A selected ion monitoring method is described for the analysis of styrene (St)-based polymers for a-methylstyrene (α- MSt) and for determining the level of α-MSt migration from St-based sheets Into 4 food simulants. The polymers are dissolved in dlchloromethane; α-MSt Is determined by direct Injection of the polymer solutions. α-MSt migration from St-based sheet to water, 4% acetic acid, 20% ethanol, and n-heptane was measured by gas chromatography/mass spectrometry, using multiple ion monitoring of Ions at mix 118,78, and 91. α-MSt can be quantltated at levels as low as 10 μ/g in the polymer and 0.01 μ/g In the food simulants. Recoveries were 83-113% from St-based sheets and 90-99% from food simulants, respectively.

scholarly journals Determination of Organic Micropollutants in Water Using Gas Chromatography-Mass Spectrometry

Proceedings ◽  
2019 ◽  
Vol 16 (1) ◽  
pp. 57
Author(s):  
Marek Król ◽  
Mariusz Dudziak
Keyword(s):  
Mass Spectrometry ◽  
Detection Sensitivity ◽  
Gas Chromatography Mass Spectrometry ◽  
Determination Method ◽  
Organic Micropollutants ◽  
Selected Ion Monitoring ◽  
Detection Mode ◽  
Full Scan ◽  
Ethylhexyl Phthalate

In this study a determination method has been developed for seven different micropollutants, that were selected to represent different compound groups. The selected compounds were: 4-nonylphenol (4-NP), 4-octylphenol (4-OP), anthracene (Ant), alachlor (Ac), heptachlor (Hc), heptachlor epoxide (Hce), and bis(2-ethylhexyl)phthalate (DEHP). Chromatographic separation and mass spectrometer detection conditions were optimized to achieve the best micropollutants separation and the best detection sensitivity. A calibration curves were created at different calibration levels suited of each type of detection mode (Full Scan and Selected Ion Monitoring) and limits of detection (LOD) and limits of quantification (LOQ) were calculated. Furthermore, recovery values were determined for each compound in spiked water samples at levels equal to 10%, 50%, and 90% of the calibration curve range and compared to other studies in which similar methods of determination were used.

Versatile, efficient system for extracting drugs from urine for gas chromatographic/mass spectrometric analysis.

1989 ◽  
Vol 35 (10) ◽  
pp. 2100-2103 ◽  
Author(s):  
K E Brooks ◽  
N B Smith
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Mass Spectrometric ◽  
Gas Chromatography Mass Spectrometry ◽  
Spectrometric Analysis ◽  
Efficient System ◽  
Carboxylate Groups ◽  
Amino Amide ◽  
Alcoholic Hydroxyl ◽  
Chromatographic Mass

Abstract This is a method for efficiently extracting a wide variety of drugs from urine for toxicological analysis by gas chromatography/mass spectrometry. Before extraction, the urine sample is acetylated, diluted with an equal volume of water, and saturated with NaCl. This solution is then mixed with an equal volume of dichloromethane/acetone (2:1 by vol). The organic (top) phase is aspirated and evaporated, and the residue is redissolved in a suitable solvent for injection or further derivatization. This procedure is suitable for all drugs except carboxylate-containing drugs, which may be isolated by replacing the acetylation step with acidification of the urine to pH 2. Studies with 16 drugs containing amino, amide, alcoholic hydroxyl, phenolic hydroxyl, carboxylate groups, or combinations thereof, showed that all drugs except theophylline and benzoylecgonine were extracted with analytical recoveries ranging from 70% to 100%.

scholarly journals Determination of dimethoxyphenethylamine derivatives in urine by deuterium labeled internal standards

2008 ◽  
Vol 73 (12) ◽  
pp. 1223-1233 ◽  
Author(s):  
Ya-Zhu Xu ◽  
Huei-Ru Lin ◽  
Ahai-Chang Lua ◽  
Chinpiao Chen
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Quantitative Analysis ◽  
Forensic Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Internal Standards ◽  
Chromatography Mass Spectrometry ◽  
Accuracy And Precision

The use of gas chromatography-mass spectrometry (GC-MS) in forensic analysis is increasing. To exploit fully the capabilities of MS, labeled standards, that can be used to improve the performance of the quantitative analysis, and to increase accuracy and precision, are required. A series of deuterated internal standards, corresponding to the 2C-series of phenethylamine derivatives, including 4-bromo-2,5-dimethoxyphenethylamine-d6 (2C-B), 4-chloro- 2,5-dimethoxyphenethylamine-d6 (2C-C), 4-iodo-2,5-dimethoxy-phenethylamine-d6 (2C-I), 4-ethylthio-2,5-dimethoxy-phenethylamine-d6 (2C-T-2) and 2,5-dimethoxy-4-n-propylthiophenethylamine-d6 (2C-T-7), were synthesized. These deuterated compounds were used to analyze for the corresponding unlabeled compounds in urine. The analysis was performed using GC-MS, with the selected ion monitoring (SIM) technique, whereby good results were achieved.

Determination of testosterone in plasma from men by gas chromatography/mass spectrometry, with high-resolution selected-ion monitoring and metastable peak monitoring.

1981 ◽  
Vol 27 (7) ◽  
pp. 1165-1170 ◽  
Author(s):  
E M Finlay ◽  
S J Gaskell
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
High Resolution ◽  
External Quality Assessment ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Internal Standards ◽  
Metastable Peak ◽  
Chromatography Mass Spectrometry

Abstract Highly specific methods are described for determining testosterone in plasma or serum from men. Extract fractions obtained by selective isolation procedures are converted to tert-butyldimethylsilyl (TBDMS) oximes/TBDMS ethers or methyl oximes/TBDMS ethers and analyzed by gas chromatography/mass spectrometry in the high-resolution selected-ion monitoring or metastable peak-monitoring modes. [2H3]Testosterone and unlabeled 17-epitestosterone are used as the respective internal standards. When we applied the two procedures to analysis of samples of pooled plasma and serum used for external quality assessment of routine assays, the results agreed well. Interlaboratory values for mean concentrations obtained by routine immunoassays (y) consistently exceeded values obtained by our technique (x), although the values closely correlated (r = 0.997; y = 1.008x + 0.564 nmol/L).

scholarly journals Different Acute Effects of the Tyrosine Hydroxylase Inhibitors a-Methyl-p-Tyrosine and 3-Iodo-L-Tyrosine on Hypothalamic Noradrenaline Activity and Adrenocorticotrophin Release in the Rat

1983 ◽  
Vol 36 (6) ◽  
pp. 519 ◽  
Author(s):  
GA Smythe ◽  
JE Bradshaw
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Tyrosine Hydroxylase ◽  
Homovanillic Acid ◽  
Prolactin Secretion ◽  
Gas Chromatography Mass Spectrometry ◽  
Acute Effects ◽  
Acth Secretion ◽  
Selected Ion Monitoring ◽  
Internal Standards

Computerized gas chromatography-mass spectrometry techniques using selected ion monitoring and deuterated internal standards were used to assay simultaneously the medial basal hypothalamic concentrations of dopamine (DA) and noradrenaline (NA) and their major metabolites in individual rats 30 min after the administration of two different inhibitors of tyrosine hydroxylase, a-methyl-ptyrosine (a-MT) and 3-iodo-L-tyrosine (MIT). Consistent with inhibition of DA synthesis, administration of both a-MT and MIT resulted in marked reductions (P<O� 005) in the hypothalamic concentrations of DA and its metabolite homovanillic acid as well as in highly significant increases in prolactin secretion. a-MT administration, but not MIT, resulted in a highly significant decrease in NA concentration and a highly significant increase in the concentration of the NA metabolite 3,4- dihydroxyphenylethyleneglycol (DHPG). The hypothalamic ratio DHPG/NA was thus markedly increased (P<O� 005) by a-MT indicating increased NA neuronal activity. a-MT administration also resulted in increased ACTH secretion (P<O� 0005), an effect not observed following MIT

scholarly journals Identification and Analytical Characterization of a Novel Synthetic Cannabinoid-Type Substance in Herbal Material in Europe

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 793
Author(s):  
Emmanouil D. Tsochatzis ◽  
Joao Alberto Lopes ◽  
Margaret V. Holland ◽  
Fabiano Reniero ◽  
Giovanni Palmieri ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Cannabinoid Receptor ◽  
Analytical Data ◽  
Synthetic Cannabinoids ◽  
Synthetic Cannabinoid ◽  
Gas Chromatography Mass Spectrometry ◽  
New Psychoactive Substances ◽  
Synthetic Cannabinoid Receptor Agonists ◽  
Analytical Laboratories

The rapid diffusion of new psychoactive substances (NPS) presents unprecedented challenges to both customs authorities and analytical laboratories involved in their detection and characterization. In this study an analytical approach to the identification and structural elucidation of a novel synthetic cannabimimetic, quinolin-8-yl-3-[(4,4-difluoropiperidin-1-yl) sulfonyl]-4-methylbenzoate (2F-QMPSB), detected in seized herbal material, is detailed. An acid precursor 4-methyl-3-(4,4-difluoro-1-piperidinylsulfonyl) benzoic acid (2F-MPSBA), has also been identified in the same seized material. After extraction from the herbal material the synthetic cannabimimetic, also referred to as synthetic cannabinoid receptor agonists or “synthetic cannabinoids”, was characterized using gas chromatography-mass spectrometry (GC-MS), 1H, 13C, 19F and 15N nuclear magnetic resonance (NMR) and high-resolution tandem mass spectrometry (HR-MS/MS) combined with chromatographic separation. A cheminformatics platform was used to manage and interpret the analytical data from these techniques.

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