scholarly journals Codeine Concentration in Hair after Oral Administration Is Dependent on Melanin Content

1999 ◽  
Vol 45 (9) ◽  
pp. 1485-1494 ◽  
Author(s):  
Robert Kronstrand ◽  
Sophie Förstberg-Peterson ◽  
Bertil KÅgedal ◽  
Johan Ahlner ◽  
Göran Larson
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Human Subjects ◽  
Area Under The Curve ◽  
Gas Chromatography Mass Spectrometry ◽  
Melanin Content ◽  
Exponential Relationship ◽  
Chromatography Mass Spectrometry ◽  
Hair Samples ◽  
Drug Incorporation

Abstract Background: Analysis of drugs in hair has been used on a qualitative basis to estimate earlier exposure to drugs. Clinical applications are rare because of the lack of dose–response relationships in the studies performed to date, and questions remain regarding the mechanisms of drug incorporation into hair. Several human studies have shown differences in drug accumulation between pigmented and nonpigmented hair. However, the melanin concentration in hair was not determined and correlated to the amount of drug incorporated. Methods: Nine human subjects were given codeine as a single oral dose, and plasma codeine concentrations were determined for 24 h, using gas chromatography–mass spectrometry. Hair samples were obtained weekly for a month. Total melanin, eumelanin, and codeine were measured quantitatively in hair samples by spectrophotometry, HPLC, and gas chromatography–mass spectrometry, respectively. Results: There was an exponential relationship between codeine and melanin concentrations in hair, (r2 = 0.95 with total melanin and r2 = 0.83 with eumelanin). After normalizing the results by the area under the curve for codeine in plasma, we obtained r2 = 0.86 for codeine vs total melanin and r2 = 0.90 vs eumelanin. Conclusions: Our results stress the importance of melanin determination when measuring drugs in hair. We postulate that analysis of drug concentration in hair may be worthwhile in the monitoring of drug compliance if the results are normalized for melanin content.

scholarly journals Hybrid Solid-Phase Extraction for Selective Determination of Methamphetamine and Amphetamine in Dyed Hair by Using Gas Chromatography–Mass Spectrometry

Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2501 ◽  
Author(s):  
Nam Hee Kwon ◽  
Yu Rim Lee ◽  
Hee Seung Kim ◽  
Jae Chul Cheong ◽  
Jin Young Kim
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Phase Extraction ◽  
Selective Determination ◽  
Chromatography Mass Spectrometry ◽  
Hair Samples

Sample preparation is an important step in the isolation of target compounds from complex matrices to perform their reliable and accurate analysis. Hair samples are commonly pulverized or processed as fine cut, depending on preference, before extraction by techniques such as solid-phase extraction (SPE), liquid–liquid extraction, and other methods. In this study, a method based on hybrid solid-phase extraction (hybridSPE) and gas chromatography–mass spectrometry (GC–MS) was developed and validated for the determination of methamphetamine (MA) and amphetamine (AP) in hair. The hair samples were mechanically pulverized after washing with de-ionized water and acetone. The samples were then sonicated in methanol at 50 °C for 1 h and centrifuged at 50,000× g for 3 min. The supernatants were transferred onto the hybridSPE cartridge and extracted using 1 mL of 0.05 M methanolic hydrogen chloride. The combined solutions were evaporated to dryness, derivatized using pentafluoropropionic anhydride, and analyzed by GC–MS. Excellent linearity (R2 > 0.9998) was achieved in the ranges of 0.05–5.0 ng/mg for AP and 0.1–10.0 ng/mg for MA. The recovery was 83.4–96.8%. The intra- and inter-day accuracies were −9.4% to 5.5% and −5.1% to 3.1%, while the intra- and inter-day precisions were within 8.3% and 6.7%, respectively. The limits of detections were 0.016 ng/mg for AP and 0.031 ng/mg for MA. The validated hybridSPE method was applied to dyed hair for MA and AP extraction and compared to a methanol extraction method currently being used in our laboratory. The results showed that an additional hybridSPE step improved the recovery by 5.7% for low-concentration quality control (QC) samples and by 24.1% for high-concentration QC samples. Additionally, the hybridSPE method was compared to polymeric reversed-phase SPE methods, and the absolute recoveries for hybridSPE were 50% and 20% greater for AP (1.5 ng/mg) and MA (3.0 ng/mg), respectively. In short, the hybridSPE technique was shown to minimize the matrix effects, improving GC–MS analysis of hair. Based on the results, the proposed method proved to be effective for the selective determination of MA and AP in hair 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.

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