scholarly journals Measurement of Plasma Free Metanephrine and Normetanephrine by Liquid Chromatography–Tandem Mass Spectrometry for Diagnosis of Pheochromocytoma

2004 ◽  
Vol 50 (3) ◽  
pp. 603-611 ◽  
Author(s):  
Susan A Lagerstedt ◽  
Dennis J O’Kane ◽  
Ravinder J Singh
Keyword(s):  
Solid Phase ◽  
Atmospheric Pressure Chemical Ionization ◽  
Multiple Reaction Monitoring ◽  
Internal Standard ◽  
Ionization Source ◽  
Deming Regression ◽  
Liquid Chromatography Tandem Mass ◽  
Pressure Chemical Ionization ◽  
Pressure Chemical ◽  
Plasma Free Metanephrines

Abstract Background: Quantification of plasma free metanephrines is usually accomplished by HPLC with electrochemical detection, but sample preparation is labor-intensive and time-consuming, run times are long, and interfering substances sometimes obscure the relevant peaks. The aim of this study was to develop a sensitive and specific LC-MS/MS method for plasma free metanephrines. Methods: After solid-phase extraction, chromatographic separation of normetanephrine (NMN) and metanephrine (MN) was accomplished by use of a cyano analytical column. NMN, MN, d3-NMN, and d3-MN positive ions were detected in the multiple-reaction monitoring mode using the specific transitions m/z 166→134, 180→148, 169→137, and 183→151, respectively, with an atmospheric pressure chemical ionization source. Results: Multiple calibration curves exhibited consistent linearity and reproducibility. Interassay imprecision values (CV; n = 20) for NMN at 0.64, 1.9, and 2.7 nmol/L were 6.6%, 7.8%, and 13%, respectively. Interassay CV for MN at 0.60, 1.2, and 2.1 nmol/L (n = 20) were 9.2%, 6.8%, and 9.8%, respectively. The mean recoveries of NMN and MN relative to the internal standard were 100% and 96%, respectively. The assays were linear between 0.20 and 10.0 nmol/L. Deming regression of HPLC and LC-MS/MS results yielded slopes of 0.93 (95% confidence interval, 0.89–0.98) and 0.89 (0.85–0.93) and y-intercepts of −0.16 and 0.03 nmol/L for NMN (n = 132) and MN (n = 92), respectively. Conclusions: This novel LC-MS/MS approach provides a precise, rapid, and specific alternative method to HPLC for the quantification of the low nanomolar concentrations of free metanephrines in plasma.

scholarly journals Determination of Chloramphenicol in Bovine Milk by Liquid Chromatography/Tandem Mass Spectrometry

2003 ◽  
Vol 86 (4) ◽  
pp. 703-706 ◽  
Author(s):  
Lambert K Sørensen ◽  
Tina H Elbæk ◽  
Helga Hansen
Keyword(s):  
Solid Phase ◽  
Atmospheric Pressure Chemical Ionization ◽  
Bovine Milk ◽  
Negative Ion ◽  
Tandem Mass ◽  
Liquid Chromatography Tandem Mass ◽  
Pressure Chemical Ionization ◽  
Pressure Chemical ◽  
Negative Ion Mode

Abstract A rapid confirmatory liquid chromatographic/tandem mass spectrometic method was developed for determination of chloramphenicol in bovine milk. Chloramphenicol was extracted directly from milk by solid-phase extraction on a C18 cartridge. The extract was further cleaned up on neutral aluminium oxide. Three transition products were monitored in negative ion mode after atmospheric pressure chemical ionization. The detection capability related to the transition product of lowest abundance was 0.03 μg/kg. The mean recovery was 90% at levels of 0.1–0.2 μg/kg. The relative repeatability standard deviations were 4.3, 3.8, and 2.8% at levels of 0.1, 0.2, and 1.0 μg/kg, respectively.

scholarly journals Determination of β-Agonist Residues in Bovine Urine Using Liquid Chromatography-Tandem Mass Spectrometry

2005 ◽  
Vol 88 (1) ◽  
pp. 46-56 ◽  
Author(s):  
Leslie C Dickson ◽  
James D MacNeil ◽  
Stephen Lee ◽  
Adrian C E Fesser
Keyword(s):  
Solid Phase ◽  
Atmospheric Pressure Chemical Ionization ◽  
Multiple Reaction Monitoring ◽  
Enzymatic Digestion ◽  
Liquid Chromatograph ◽  
Bovine Urine ◽  
Liquid Chromatography Tandem Mass ◽  
Tandem Quadrupole Mass Spectrometer ◽  
Pressure Chemical Ionization ◽  
Detection Capabilities

Abstract A multiresidue method was developed and validated to screen bovine urine samples for 10 β-2-adrenergic agonistic drugs—brombuterol, cimaterol, clenbuterol, clenpenterol, isoxsuprine, mabuterol, ractopamine, ritodrine, salbutamol, and tulobuterol—at the 2 μg/L level. The method is also quantitative in the range of 1 to 4 μg/L for all analytes except salbutamol. The procedure uses enzymatic digestion, liquid–liquid extraction, and cleanup on solid-phase extraction columns, followed by detection using a liquid chromatograph-tandem quadrupole mass spectrometer operated in the positive-ion atmospheric pressure chemical ionization multiple-reaction monitoring mode. Method validation included assessment of recoveries, repeatabilities, linearity of responses, decision limits, and detection capabilities. Overall average recoveries ranged from 70–91%; recoveries were generally lower for salbutamol. The decision limits ranged from 0.4–1.0 μg/L, and detection capabilities from 0.6–1.7 μg/L.

scholarly journals A Novel Bioanalytical Method for Determination of Inotodiol Isolated from Inonotus Obliquus and Its Application to Pharmacokinetic Study

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1631
Author(s):  
Jin Hyeok Kim ◽  
Dan Gao ◽  
Chong Woon Cho ◽  
Inkyu Hwang ◽  
Hyung Min Kim ◽  
...  
Keyword(s):  
Pharmacokinetic Study ◽  
Solid Phase ◽  
Atmospheric Pressure Chemical Ionization ◽  
Multiple Reaction Monitoring ◽  
Pharmacokinetic Parameters ◽  
Inonotus Obliquus ◽  
Bioanalytical Method ◽  
Pressure Chemical Ionization ◽  
Pressure Chemical ◽  
Positive Mode

In this study, we developed a bioanalytical method using liquid chromatography coupled to triple quadrupole tandem mass spectrometry (LC-MS/MS) to apply to a pharmacokinetic study of inotodiol, which is known for its anti-cancer activity. Plasma samples were prepared with alkaline hydrolysis, liquid–liquid extraction, and solid-phase extraction. Inotodiol was detected in positive mode with atmospheric pressure chemical ionization by multiple-reaction monitoring mode using LC-MS/MS. The developed method was validated with linearity, accuracy, and precision. Accuracy ranged from 97.8% to 111.9%, and the coefficient of variation for precision was 1.8% to 4.4%. The developed method was applied for pharmacokinetic study, and the mean pharmacokinetic parameters administration were calculated as follows: λz 0.016 min−1; T1/2 49.35 min; Cmax 2582 ng/mL; Cl 0.004 ng/min; AUC0–t 109,500 ng×min/mL; MRT0–t 32.30 min; Vd 0.281 mL after intravenous administration at dose of 2 mg/kg and λz 0.005 min−1; T1/2 138.6 min; Tmax 40 min; Cmax 49.56 ng/mL; AUC0–t 6176 ng×in/mL; MRT0–t 103.7 min after oral administration. The absolute oral bioavailability of inotodiol was 0.45%, similar to nonpolar phytosterols. Collectively, this is the first bioanalytical method and pharmacokinetic study for inotodiol.

scholarly journals Simultaneous Determination of Cholecalciferol (Vitamin D3) and Ergocalciferol (Vitamin D2) in Foods by Selected Reaction Monitoring

2009 ◽  
Vol 92 (2) ◽  
pp. 511-517 ◽  
Author(s):  
Gianluca Dimartino
Keyword(s):  
Vitamin D3 ◽  
Ion Trap ◽  
Atmospheric Pressure Chemical Ionization ◽  
Internal Standard ◽  
Selected Reaction Monitoring ◽  
Vitamin D2 ◽  
Reaction Monitoring ◽  
Ionization Source ◽  
Relative Standard ◽  
Pressure Chemical Ionization

Abstract Cholecalciferol (vitamin D3) and ergocalciferol (vitamin D2) were determined simultaneously by selected reaction monitoring (SRM) mass spectrometry for different food matrixes. A small amount of starting sample was saponified and extracted before injection into a linear ion trap mass spectrometer equipped with an atmospheric pressure chemical ionization source. Dihydrotachysterol, which is absent from food and has a structure similar to that of vitamins D3 and D2, was used as an internal standard. Calibration curves for the 2 vitamins showed linearity with R2 values of 0.9999 and 0.9989 for vitamins D3 and D2, respectively. Limits of detection for vitamins D3 and D2 were 0.5 ng/g (1.3 pmol/g) and 1.75 ng/g (4.4 pmol/g) and limits of quantitation were 1.25 ng/g (3.24 pmol/g), and 3.75 ng/g (9.45 pmol/g), respectively. Accuracy and precision of the method were tested with the infant formula reference standard of the National Institute of Standards and Technology, which showed a relative standard deviation of 6. Recoveries ranged from 95 to 105. Several food products were tested with AOAC Method 982.29, which is currently in use for vitamins D3 and D2, and results were comparable within 6.

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