Positive Ion Ejection System (PIES).

Background: A simple and sensitive Ultra Performance Liquid Chromatography-Mass Spectrometry method was developed and validated to measure the concentrations of Alogliptin (ALO), Linagliptin (LIN), Saxagliptin (SAX), and Sitagliptin (SIT) using Pioglitazone (PIO) as an internal standard. Methods: Chromatographic separation of six gliptins was achieved on a C-18 column (100×2.1 mm, 2.7 μm) using a mobile phase consisting of formic acid in water, 0.1%v/v: acetonitrile in gradient elution. Electrospray ionization (ESI) source was operated in the positive ion mode. Targeted MS/MS mode on a QTOF MS was used to quantify the drug utilizing the transitions of 340.1(m/z), 473.2 (m/z), 316.2 (m/z), 408.1 (m/z), and 357.1 (m/z) for ALO, LIN, SAX, SIT and PIO respectively. Results: As per ICH Q2R1 guidelines, a detailed validation of the method was carried out and the standard curves were found to be linear over the concentration ranges of 1516.0-4548.1 ng mL-1, 519.8- 1559.4 ng mL-1, 1531.4-4594.3 ng mL-1and 1519.6-4558.8 ng mL-1 for ALO, LIN, SAX and SIT respectively. Precision and accuracy results were within the acceptable limits. The mean recovery was found to be 98.8 _ 0.76 % (GEM), 102.2 _ 1.59 % (LIN), 95.3 _ 2.74 % (SAX) and 99.2 _ 1.75 % (SIT) respectively. Conclusions: The optimized validated UPLC QTOF-MS/MS method offered the advantage of shorter analytical times and higher sensitivity and selectivity. The optimized method is suitable for application in quantitative analysis of pharmaceutical dosage forms for QC laboratory.

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Measurement and theoretical characterization of electronic absorption spectrum of neutral chrysene (C18H12) and its positive ion in H3BO3 matrix

Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy ◽

10.1016/j.saa.2006.11.009 ◽

2007 ◽

Vol 68 (1) ◽

pp. 156-164 ◽

Cited By ~ 3

Author(s):

Mudassir M. Husain

Keyword(s):

Absorption Spectrum ◽

Electronic Absorption Spectrum ◽

Electronic Absorption ◽

Theoretical Characterization ◽

Positive Ion

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Structure of the butadiene positive ion

Transactions of the Faraday Society ◽

10.1039/tf9635901695 ◽

1963 ◽

Vol 59 ◽

pp. 1695 ◽

Cited By ~ 4

Author(s):

D. A. Hutchinson

Keyword(s):

Positive Ion

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The Development and Validation of a Novel Designer Benzodiazepines Panel by LC–MS-MS

Journal of Analytical Toxicology ◽

10.1093/jat/bkab013 ◽

2021 ◽

Author(s):

Rebecca A Mastrovito ◽

Donna M Papsun ◽

Barry K Logan

Keyword(s):

Illicit Drug ◽

Liquid Extraction ◽

Electrospray Tandem Mass Spectrometry ◽

Method Performance ◽

Internal Standards ◽

Liquid Liquid Extraction ◽

Relative Standard ◽

Development And Validation ◽

Positive Ion ◽

Designer Benzodiazepines

Abstract Novel illicit benzodiazepines are among the most active areas of new illicit drug manufacture and use. We describe a method for the detection and quantification of etizolam and its metabolite α-hydroxyetizolam, flubromazolam, clonazolam, diclazepam, delorazepam, bromazepam, flubromazepam, phenazepam, flualprazolam, flunitrazolam, and nitrazolam in human whole blood. After addition of internal standards, samples are buffered and extracted using a liquid–liquid extraction. Analysis is performed using positive-ion electrospray tandem mass spectrometry for detection and quantitation. Calibration ranges were established based on the method performance and differed from compound to compound. Replicates at the lowest calibration point for each compound performed within 5% of CV (Coefficient of Variation). The correlation coefficient was >0.990 for all compounds. Relative standard deviation for all compounds was ≤10% of CV and accuracy was ±10% for both within- and between-run experiments. The maximum average intra- and inter-run imprecision were 5.7%. The maximum average intra- and inter-run imprecision was −8.7%. As part of evaluating the scope for relevancy, samples testing positive in immunoassay but confirmed to be negative in traditional benzodiazepine confirmation method were re-analyzed using this method. The presence of at least one novel benzodiazepine was identified in 70% of these samples. The appearance of these novel “designer” benzodiazepines demonstrates the challenge for toxicology testing and the need for continually updated confirmation methods.

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