scholarly journals A Simple Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry Method for Measurement of Cortisol Level in Human Saliva

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Syed N. Alvi ◽  
Muhammad M. Hammami
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Cortisol Level ◽  
Mobile Phase ◽  
Room Temperature ◽  
Human Saliva ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

A simple ultraperformance liquid chromatography-tandem mass spectrometry assay for measurement of cortisol level in human saliva was developed and validated. Saliva samples containing cortisol were spiked with tolperisone as internal standard (IS) and extracted with a mixture of methyl tert-butyl ether and hexane (8:2, v:v). After solvent evaporation, residue was reconstituted in 100 μl mobile phase. Analysis was performed on Atlantis dC18 column (2.1 × 100 mm, 3 μm particle size) with a mobile phase composed of acetonitrile and 2 mM ammonium acetate (50:50, v:v) and delivered at a flow rate of 0.3 ml/minute. Mass spectrometry acquisition was performed with multiple reaction monitoring in positive-ion mode for cortisol and IS (m/z: 363.1 → 121.0 and 246.0 → 97.9, respectively). Retention times of cortisol and IS were about 1.35 and 2.45 minutes, respectively. The relationship between cortisol level and peak area ratio of cortisol to IS was linear in the range of 0.5-100 ng/ml. Intra- and interday coefficient of variation and bias were ≤ 9.0% and ≤12.0%, respectively. Mean extraction recoveries of cortisol and IS from saliva samples were 92% and 94%, respectively. Using the method, cortisol was found to be ≥ 86% stable in processed (24 hours at room temperature or 48 hours at -20°C) and ≥ 91% stable in unprocessed (24 hours at room temperature or 20 weeks at -20°C) saliva samples. Further, the method was successfully applied to determine daily cortisol profile in saliva samples of a healthy volunteer.

scholarly journals Validation and clinical application of a method to quantify efavirenz in cervicovaginal secretions from flocked swabs using liquid chromatography tandem mass spectrometry

2021 ◽  
Vol 6 ◽  
pp. 246
Author(s):  
Adeniyi Olagunju ◽  
Jacinta Nwogu ◽  
Oluwasegun Eniayewu ◽  
Shakir Atoyebi ◽  
Alieu Amara ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Room Temperature ◽  
Female Genital Tract ◽  
Weighting Factor ◽  
Tandem Mass ◽  
Triple Quadrupole Mass Spectrometer ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

Background: A liquid chromatography tandem mass spectrometry method to quantify drugs in dried cervicovaginal secretions from flocked swabs was developed and validated using the antiretroviral efavirenz as an example. Methods: Cervicovaginal swabs (CVS) were prepared by submerging flocked swabs in efavirenz-spiked matrix. Time to full saturation, weight uniformity, recovery and room temperature stability were evaluated. Chromatographic separation was on a reverse-phase C18 column by gradient elution using 1mM ammonium acetate in water/acetonitrile at 400 µL/min. Detection and quantification were on a TSQ Quantum Access triple quadrupole mass spectrometer operated in negative ionisation mode. The method was used to quantify efavirenz in CVS samples from human immunodeficiency virus (HIV)-positive women in the VADICT study (NCT03284645). A total of 98 samples (35 paired intensive CVS and DBS samples, 14 paired sparse CVS and DBS samples) from 19 participants were available for this analysis. Results: Swabs were fully saturated within 15 seconds, absorbing 128 µL of matrix with coefficient of variation (%CV) below 1.3%. The method was linear with a weighting factor (1/X) in the range of 25-10000 ng/mL with inter- and intra-day precision (% CV) of 7.69-14.9%, and accuracy (% bias) of 99.1-105.3%. Mean recovery of efavirenz from CVS was 83.8% (%CV, 11.2) with no significant matrix effect. Efavirenz remained stable in swabs for at least 35 days after drying and storage at room temperature. Median (range) CVS efavirenz AUC0-24h was 16370 ng*h/mL (5803-22088), Cmax was 1618 ng/mL (610-2438) at a Tmax of 8.0 h (8.0-12), and Cmin was 399 ng/mL (110-981). Efavirenz CVS:plasma AUC0-24 ratio was 0.41 (0.20-0.59). Conclusions: Further application of this method will improve our understanding of the pharmacology of other therapeutics in the female genital tract, including in low- and middle-income countries.

scholarly journals Liquid Chromatography Tandem Mass Spectrometry Method for Ultra-Trace Analysis of Organic UV Filters in Environmental Water Samples

2020 ◽  
Vol 71 (1) ◽  
pp. 92-99
Author(s):  
Florentina Laura Chiriac ◽  
Iuliana Paun ◽  
Florinela Pirvu ◽  
Luoana Florentina Pascu ◽  
Marcela Niculescu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Surface Water ◽  
Tandem Mass Spectrometry ◽  
Mobile Phase ◽  
Solid Phase ◽  
Environmental Water ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

A liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) method was developed and validated for the simultaneous determination of six organic compounds (2-hydroxy benzophenone, 4-hydroxy benzophenone, 2,2�,4,4�-tetrahydroxy benzophenone, 2,4-dyhydroxy benzophenone, 4,4�-dyhydroxy benzophenone, 2,2�-dyhydroxy-4-methoxy-benzophenone) used as UV filters in personal care products used to protect against UV radiation. The major concern about this type of pollutants is due to their persistence and bioaccumulation potential in the environment and aquatic organisms and for their endocrine disruptor properties. Solid phase extraction was used for sample preparation, followed by liquid chromatography tandem mass spectrometry analysis. Benzophenone derivatives were analyzed on a Phenomenex Luna C18 column (150 x 2.0 mm, 3.0 �m) with the mobile phase run in gradient mode with a mixture of aqueous 0.1% formic acid and acetonitrile as the mobile phase components (at a flow rate of 0.2 mL/min). MS detector response was linear, on the tested concentration domain from 1 to 100 μg/L with correlation coefficient R2 ] 0.998. The recoveries of benzophenone derivatives after solid phase extraction procedure from surface water was found to be ]81% for surface water and higher than 79% for wastewater matrix. The standard deviation values for intra-day precision were situated between 7.67% and 9.88% for lower concentration and 7.27% and 8.86% for higher concentration respectively. The limits of quantitation were calculated for both environmental water matrices (1.6-4.1 ng/L for surface water and 3.3-8.2 ng/L for wastewater). This method can be applied for benzophenone derivatives detection in real environmental samples.

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