The Role of Gas Chromatography/Mass Spectrometry: Instrumental Techniques in Forensic Urine Drug Testing

1998 ◽  
Vol 18 (4) ◽  
pp. 631-649 ◽  
Author(s):  
Michael Lehrer
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Drug Testing ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Urine Drug Testing ◽  
Urine Drug

scholarly journals Determination of Mammalian Lignans in Biological Samples by Modified Gas Chromatography/Mass Spectrometry

2007 ◽  
Vol 90 (3) ◽  
pp. 641-646 ◽  
Author(s):  
Ajay Bommareddy ◽  
Bhanu L Arasada ◽  
Duane P Mathees ◽  
Chandradhar Dwivedi
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Gas Chromatography Mass Spectrometry ◽  
Serum Samples ◽  
Selected Ion Monitoring ◽  
Beneficial Effects ◽  
Chromatography Mass Spectrometry ◽  
Flaxseed Meal

Abstract Lignans in flaxseed have been part of the human diet for centuries. In 1955, the isolation and structure of the lignan derivative secoisolariciresinol diglucoside (SDG) was reported. The biological role of SDG and mammalian lignan metabolites enterodiol and enterolactone was initially reported 20 years later. Experimental evidences showed the beneficial effects of lignans on breast, colon, and thyroid cancer. A modified gas chromatography/mass spectrometry (GC/MS) assay was developed for lignans in serum and colon samples of rats fed flaxseed meal. The method developed for the analysis of metabolites involves extraction and derivatization of samples and quantitative analysis by selected ion monitoring using GC/MS. The levels of lignan metabolites enterodiol and enterolactone were determined to be 0.013 and 0.23 M in serum samples and 0.008 and 1.63 M in colon samples.

scholarly journals Diagnosis of COVID-19 by exhaled breath analysis using gas chromatography-mass spectrometry

2021 ◽  
pp. 00139-2021
Author(s):  
Wadah Ibrahim ◽  
Rebecca L. Cordell ◽  
Michael J. Wilde ◽  
Matthew Richardson ◽  
Liesl Carr ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Area Under The Curve ◽  
Gas Chromatography Mass Spectrometry ◽  
Exhaled Breath ◽  
Non Invasive ◽  
Clinical Probability ◽  
Chromatography Mass Spectrometry ◽  
Exhaled Breath Analysis

BackgroundThe ongoing COVID-19 pandemic has claimed over two and a half million lives worldwide so far. SARS-CoV-2 infection is perceived to be seasonally recurrent and a rapid non-invasive biomarker to accurately diagnose patients early-on in their disease course will be necessary to meet the operational demands for COVID-19 control in the coming years.ObjectiveTo evaluate the role of exhaled breath volatile biomarkers in identifying patients with suspected or confirmed COVID-19 infection, based on their underlying PCR status and clinical probability.MethodsA prospective, real-world, observational study recruiting adult patients with suspected or confirmed COVID-19 infection. Breath samples were collected using a standard breath collection bag, modified with appropriate filters to comply with local infection control recommendations and samples were analysed using gas chromatography-mass spectrometry (TD-GC-MS).Findings81 patients were recruited between April 29th to July 10th, 2020, of whom 52/81 (64%) tested positive for COVID-19 by RT-PCR. A regression analysis identified a set of seven exhaled breath features (benzaldehyde, 1-propanol, 3, 6-methylundecane, camphene, beta-cubebene, Iodobenzene, and an unidentified compound) that separated PCR positive patients with an area under the curve (AUC): 0.836, sensitivity: 68%, specificity: 85%.ConclusionsGC-MS detected exhaled breath biomarkers were able to identify PCR positive COVID-19 patients. External replication of these compounds is warranted to validate these results.

Severe isopropanolemia without acetonemia or clinical manifestations of isopropanol intoxication

1993 ◽  
Vol 39 (9) ◽  
pp. 1922-1925 ◽  
Author(s):  
K M Chan ◽  
E T Wong ◽  
W S Matthews
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Serum Concentration ◽  
Half Life ◽  
Clinical Manifestations ◽  
Gas Chromatography Mass Spectrometry ◽  
Toxicological Analysis ◽  
Chromatography Mass Spectrometry ◽  
Osmolal Gap

Abstract This is the first reported case of severe isopropanolemia in a patient who did not experience associated clinical manifestations and acetonemia. The patient was found lying face down in a hotel lobby but at admission was alert and oriented to place and person. Toxicological analysis of the patient's serum revealed the presence of isopropanol at a concentration of 72 mmol/L. An increased serum osmolal gap (81 mOsm/kg) was also observed. The serum concentration of isopropanol decreased to 9.5 mmol/L 15.5 h after admission with an estimated half-life of elimination of 5-7 h. No serum acetone was detected throughout the patient's hospitalization. The identity of isopropanol was confirmed by gas chromatography/mass spectrometry. The patient remained awake and alert while in the hospital and was discharged 5 days after admission. These unusual findings raise some fundamental questions about the role of isopropanol conversion to acetone in the manifestation of symptoms usually associated with isopropanol intoxication.

Lowering the federally mandated cannabinoid immunoassay cutoff increases true-positive results

1994 ◽  
Vol 40 (5) ◽  
pp. 729-733 ◽  
Author(s):  
M A Huestis ◽  
J M Mitchell ◽  
E J Cone
Keyword(s):  
Mass Spectrometry ◽  
Human Services ◽  
Drug Testing ◽  
Gas Chromatography Mass Spectrometry ◽  
True Positive ◽  
Health And Human Services ◽  
Urine Drug Testing ◽  
Urine Drug ◽  
Sensitivity Specificity ◽  
Positive Results

Abstract Proposed changes to the Health and Human Services Guidelines for forensic urine drug testing will lower the required cannabinoid immunoassay cutoff concentration from 100 to 50 micrograms/L. We investigated the effect of this change on the sensitivity, specificity, and efficiency of eight cannabinoid immunoassays: Syva Emit d.a.u. 100; Syva Emit II 100; Syva Emit d.a.u. 50; Syva Emit II 50; Roche Abuscreen Online; Roche Abuscreen radioimmunoassay; Diagnostic Reagents; and Abbott ADx. All specimens also were assayed by gas chromatography/mass spectrometry. Lowering the cutoff concentration from 100 to 50 micrograms/L increased efficiencies and sensitivities for all immunoassays, with minor decreases in specificity (1.0-2.6%). There was a 23.2-53.6% increase in the number of true-positive specimens identified. Thus, lowering the cannabinoid immunoassay cutoff concentration from 100 to 50 micrograms/L resulted in detection of a substantial number of additional true-positive specimens, with an accompanying small increase in unconfirmed positive results.

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