Marijuana Testing in Urine: Use of a Hexadeuterated Internal Standard for Extended Linearity, and Ion Trap vs Mass Selective Detector Gas Chromatograph/Mass Spectrometer Systems

1992 ◽  
Vol 38 (5) ◽  
pp. 717-719 ◽  
Author(s):  
W A Joern
Keyword(s):  
Mass Spectrometer ◽  
Ion Trap ◽  
Internal Standard ◽  
Chromatographic Peak ◽  
Gas Chromatograph ◽  
Mass Selective Detector ◽  
Peak Overlap ◽  
Trap Detector ◽  
Selective Detector

Abstract The use of a hexadeuterated internal standard for the assay of the marijuana carboxy metabolite in urine resulted in two significant improvements. First, the linearity of the procedure was increased considerably because of the minimal chromatographic peak overlap of the internal standard and carboxy metabolite derivatives. Second, again because of minimal peak overlap, the same extract could be analyzed with similar results by both the ion trap detector and mass selective detector gas chromatograph/mass spectrometer systems.

Determination of Carbadox-Related Residues in Swine Liver by Gas Chromatography/Mass Spectrometry with Ion Trap Detection

1991 ◽  
Vol 74 (4) ◽  
pp. 611-618 ◽  
Author(s):  
Martin J Lynch ◽  
Franklyn R Mosher ◽  
Richard P Schneider ◽  
Hassan G Fouda ◽  
James E Risk
Keyword(s):  
Chemical Ionization ◽  
Ion Trap ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
Isotope Dilution Analysis ◽  
Gas Chromatograph ◽  
Porcine Liver ◽  
Methyl Ester Derivative ◽  
Swine Liver

Abstract The Ion trap detector (ITD), in combination with a capillary gas chromatograph and under chemical ionization conditions, offers sufficient sensitivity to determine carbadoxrelated residues as the methyl ester derivative of quinoxaline- 2-carboxylic acid at 3 μg/kg or higher in porcine liver. A tetradeuterated internal standard of QME effectively compensates for losses incurred during sample preparation. The method produced mean levels of 3.3 (±0.5), 5.5 (±0.8), and 10.1 (±0.9) μg/kg for liver fortified at 3, 5, and 10 μg/kg. When applied to analysis of samples containing incurred residues of 14C-carbadox at the low μg/kg level, results were comparable to those obtained by reverse isotope dilution analysis.

scholarly journals Optimal Extraction of Ocimum basilicum Essential Oil by Association of Ultrasound and Hydrodistillation and Its Potential as a Biopesticide Against a Major Stored Grains Pest

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2781 ◽  
Author(s):  
Eridiane da Silva Moura ◽  
Lêda Rita D’Antonino Faroni ◽  
Fernanda Fernandes Heleno ◽  
Alessandra Aparecida Zinato Rodrigues ◽  
Lucas Henrique Figueiredo Prates ◽  
...  
Keyword(s):  
Biological Activity ◽  
Essential Oil ◽  
Insect Pests ◽  
Extraction Process ◽  
Ocimum Basilicum ◽  
Gas Chromatograph ◽  
Drying Temperature ◽  
Mass Selective Detector ◽  
Potential Control ◽  
Selective Detector

The essential oil of basil (Ocimum basilicum) has significant biological activity against insect pests and can be extracted through various techniques. This work aimed to optimize and validate the extraction process of the essential oil of O. basilicum submitted to different drying temperatures of the leaves and extracted by the combination of a Clevenger method and ultrasound. The biological activity of the extracted oil under different conditions was evaluated for potential control of Sitophilus zeamais. The extraction method was optimized according to the sonication time by ultrasound (0, 8, 19, 31 and 38 min) and hydrodistillation (20, 30, 45, 60 and 70 min) and drying temperature (20, 30, 45, 60 and 70 °C). The bioactivity of the essential oil was assessed against adults of S. zeamais and the effects of each variable and its interactions on the mortality of the insects were evaluated. The best yield of essential oil was obtained with the longest sonication and hydrodistillation times and the lowest drying temperature of leaves. Higher toxicity of the essential oil against S. zeamais was obtained by the use of ultrasound for its extraction. The identification and the relative percentage of the compounds of the essential oil were performed with a gas chromatograph coupled to a mass selective detector. The performance of the method was assessed by studying selectivity, linearity, limits of detection (LOD) and quantification (LOQ), precision and accuracy. The LOD and LOQ values for linalool were 2.19 and 6.62 µg mL−1 and for estragole 2.001 and 6.063 µg mL−1, respectively. The coefficients of determination (R2) were >0.99. The average recoveries ranged between 71 and 106%, with coefficient of variation ≤6.4%.

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