scholarly journals Comparison of the levels of 8-hydroxyguanine in DNA as measured by gas chromatography mass spectrometry following hydrolysis of DNA by Escherichia coli Fpg protein or formic acid

2000 ◽  
Vol 28 (15) ◽  
pp. 75e-75 ◽  
Author(s):  
H. Rodriguez
Keyword(s):  
Mass Spectrometry ◽  
Escherichia Coli ◽  
Gas Chromatography ◽  
Formic Acid ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Hydrolysis Of ◽  
Hydrolysis Of Dna

Benzodiazepines identified by capillary gas chromatography-mass spectrometry, with specific ion screening used to detect benzophenone derivatives.

1989 ◽  
Vol 35 (7) ◽  
pp. 1394-1398 ◽  
Author(s):  
C E Jones ◽  
F H Wians ◽  
L A Martinez ◽  
G J Merritt
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Forensic Toxicology ◽  
Urine Samples ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Selection Mode ◽  
Unequivocal Identification ◽  
Hydrolysis Of ◽  
Derivatives Of

Abstract We developed algorithms for confirmation and identification of benzodiazepines and their metabolites, initially detected in urine samples by enzyme-multiplied immunoassay (EMIT). These algorithms are based on the pattern of benzophenone derivatives of benzodiazepines obtained by gas chromatography-mass spectrometry (GC-MS) with use of a modified specific ion selection mode. Benzophenone derivatives were produced by acid hydrolysis of urine samples containing benzodiazepines and (or) their metabolites. We present mass spectra of the newer benzodiazepines--alprazolam, midazolam, and triazolam--and we determined the detection limit (0.2 mg/L) for these drugs as measured with the EMIT d.a.u. benzodiazepine assay and the ETS instrument (both from Syva Co.). We conclude that these algorithms are useful mostly in forensic toxicology in which unequivocal identification of benzodiazepines is the desired goal.

Improvements on Enzymatic Hydrolysis of Human Hair for Illicit Drug Determination by Gas Chromatography/Mass Spectrometry

2007 ◽  
Vol 79 (22) ◽  
pp. 8564-8570 ◽  
Author(s):  
Martha Míguez-Framil ◽  
Antonio Moreda-Piñeiro ◽  
Pilar Bermejo-Barrera ◽  
Patricia López ◽  
María Jesús Tabernero ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Enzymatic Hydrolysis ◽  
Human Hair ◽  
Illicit Drug ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Drug Determination ◽  
Hydrolysis Of

Depletion of Residues from Milk and Blood of Cows Dosed Orally and Intravenously with Sulfamethazine

1994 ◽  
Vol 77 (4) ◽  
pp. 895-900
Author(s):  
Gaylord D Paulson ◽  
Vernon J Feil ◽  
Richard G Zaylskie ◽  
John M Giddings ◽  
William D Slanger
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Body Weight ◽  
Reversed Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Reversed Phase Chromatography ◽  
Mass Spectral ◽  
Chromatography Mass Spectrometry ◽  
Methyl Derivatives ◽  
Hydrolysis Of

Abstract Cows were dosed orally (n=4) or intravenously (n = 4) with sulfamethazine [sulmet; 4-amino-N(4,6-dimethyl-2-pyrimidinyl)benzenesutfonamide] for 5 consecutive days (220 mg/kg of body weight on day 1 and 110 mg/kg on days 2–5). The concentrations of sulmet, N4-acetylsulfamethazine (Ac-sulmet), and the N4-lactose conjugate of sulfamethazine (lac-sulmet) were measured in milk and blood collected at 24 h intervals after the last doses of sulmet were given. The method of analysis included (1) spiking of samples with known amounts of 13C6-labeled reference compounds, (2) resolution of the 3 compounds by reversed- phase chromatography, (3) hydrolysis of lac-sulmet, (4) treatment with diazomethane to yield N1-methyl derivatives, and (5) gas chromatography/mass spectrometry. The ratios of intensities of selected mass spectral ions containing 12C6 and the corresponding ions containing 13C6 were used for residue quantitation. Sulmet, which was always the most abundant residue in the blood, decreased to less than 100 ppb 4 days after the last doses were given and to less than 10 ppb 7 days after the last doses. The concentrations of sulmet in milk were approximately one fifth the concentrations of sulmet in blood. The concentrations of lac-sulmet and Ac-sulmet in milk were lower than the concentrations of sulmet in milk.

scholarly journals A New Gas Chromatography–Mass Spectrometry Method for Simultaneous Determination of Total and Free trans-3′-Hydroxycotinine and Cotinine in the Urine of Subjects Receiving Transdermal Nicotine

1999 ◽  
Vol 45 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Allena J Ji ◽  
George M Lawson ◽  
Rodger Anderson ◽  
Lowell C Dale ◽  
Ivana T Croghan ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Simultaneous Determination ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Transdermal Nicotine ◽  
Selective Ion Monitoring ◽  
Lower Limits ◽  
Hydrolysis Of

Abstract trans-3′-Hydroxycotinine (THOC) has been recognized as the most abundant metabolite of nicotine. In an attempt to assess THOC and cotinine (COT) concentrations during nicotine transdermal therapy, we developed a new quantitative gas chromatography–mass spectrometry (GC–MS) method for simultaneous determination of total and free THOC and COT in human urine. The method utilizes the following: (a) hydrolysis of conjugated THOC and COT by β-glucuronidase; (b) basic extraction of THOC and COT with mixed dichloromethane and n-butyl acetate; (c) derivatization of THOC with bis(trimethylflurosilyl)acetamide; and (d) separation and identification by GC–MS with selective ion monitoring. Lower limits of quantification for the assay were 50 and 20 μg/L for THOC and COT, respectively. The intra- and interassay CVs were 4.4% and 11% for THOC, and 3.9% and 10% for COT at 1000 μg/L. The results from six consecutive 24-h urine collections in 71 subjects administered daily transdermal nicotine doses of 11, 22, and 44 mg showed that, on average, free THOC was 76% of total THOC and free COT was 48% of total COT in all subjects. THOC is the major metabolite of nicotine and constitutes 20% of total nicotine intake at steady state, whereas urinary nicotine and COT excretion were 8% and 17%, respectively. The method is useful for simultaneous determination of free and total THOCand COT and can be used to assess the urinary excretion of these metabolites during transdermal nicotine therapy.

scholarly journals Simultaneous identification and quantitation of codeine, morphine, hydrocodone, and hydromorphone in urine as trimethylsilyl and oxime derivatives by gas chromatography–mass spectrometry

1997 ◽  
Vol 43 (6) ◽  
pp. 1029-1032 ◽  
Author(s):  
Larry A Broussard ◽  
Lance C Presley ◽  
Thomas Pittman ◽  
Randy Clouette ◽  
Gary H Wimbish
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Solid Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Chromatography Mass Spectrometry ◽  
Oxime Derivatives ◽  
Simultaneous Identification ◽  
Hydrolysis Of

Abstract Following enzymatic hydrolysis of urine, a gas chromatography–mass spectrometry method for the simultaneous determination of codeine, morphine, hydrocodone, and hydromorphone uses hydroxylamine to form oxime derivatives of the keto-opiates (i.e., hydrocodone, hydromorphone, oxycodone, and oxymorphone). These trimethylsilyl-derivatized forms no longer interfere with the detection and quantitation of codeine and morphine. Samples are extracted on solid-phase columns and quantitated by deuterated internal calibrations of each analyte with selected ion monitoring. Codeine, morphine, hydrocodone, and hydromorphone are completely separated, allowing simultaneous quantitation without interference and a chromatographic analysis time <9 min.

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