LC-tandem MS workshop updates on latest developments and applications

Abstract This paper describes a rapid and robust method utilizing a single liquid–liquid extraction for the quantitation and confirmation of chloramphenicol, florfenicol, and nitrofuran metabolites in honey. This methodology combines two previous extraction methods into a single extraction procedure and utilizes matrix-matched calibration standards and stable isotopically labeled standards to improve quantitation. The combined extraction procedure reduces the average extraction time by >50% when compared with previously used procedures. The drug residues were determined using two separate LC-tandem MS conditions. Validation of all the analytes was performed, with average quantitation ranging from 92 to 105% for all analytes and the RSDs for all analytes being ≤12%.

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New 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrimidinium alkaloids (phloeodictynes) from the New Caledonian shallow-water haplosclerid sponge Oceanapia fistulosa. Structural elucidation from mainly LC-tandem-MS-soft-ionization techniques and discovery of antiplasmodial activity

Organic & Biomolecular Chemistry ◽

10.1039/b313348f ◽

2004 ◽

Vol 2 (5) ◽

pp. 783 ◽

Cited By ~ 22

Author(s):

Ines Mancini ◽

Graziano Guella ◽

Michel Sauvain ◽

C�cile Debitus ◽

Anne-Ga�lle Duigou ◽

...

Keyword(s):

Shallow Water ◽

Structural Elucidation ◽

Antiplasmodial Activity ◽

Tandem Ms ◽

Soft Ionization ◽

Lc Tandem Ms

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Pilot Study for the Standardization of Insulin Immunoassays with Isotope Dilution–Liquid Chromatography/Tandem Mass Spectrometry

Clinical Chemistry ◽

10.1373/clinchem.2007.088393 ◽

2007 ◽

Vol 53 (8) ◽

pp. 1462-1469 ◽

Cited By ~ 40

Author(s):

Diego Rodríguez-Cabaleiro ◽

Katleen Van Uytfanghe ◽

Veronique Stove ◽

Tom Fiers ◽

Linda M Thienpont

Keyword(s):

Mass Spectrometry ◽

Liquid Chromatography ◽

Pilot Study ◽

Total Error ◽

Method Comparison ◽

Tandem Ms ◽

Tandem Mass ◽

Chromatography Tandem Mass Spectrometry ◽

Liquid Chromatography Tandem Mass ◽

Lc Tandem Ms

Abstract Background: An international working group convened by the American Diabetes Association (ADA) called for a reference measurement procedure for use in a trueness-based standardization project of insulin immunoassays. In view of this demand, we conducted a pilot study to investigate the feasibility of such a standardization project with our isotope dilution-liquid chromatography/tandem mass spectrometry (ID-LC/tandem MS) procedure. Methods: We evaluated the precision, accuracy, and limit of quantification (LoQ) of the ID-LC/tandem MS procedure by use of insulin-free serum supplemented with insulin to give 3 pools with concentrations of 0.0796, 0.769, and 5.56 μg/L. We conducted a pilot method comparison study with 4 immunoassays and 80 samples from fasting and glucose-stimulated patients. Results: The within-run and total imprecision (CV) ranged from 3.2% to 6.3% and from 4.9% to 12.1% (listing sequence from the high to the low pool). The recovery from supplemented insulin-free sera ranged from 101.8% to 104.1%, and the LoQ was 0.07 μg/L (12 pmol/L). Weighted Deming regression and correlation analysis of the method-comparison data showed considerable between-assay variation for the immunoassays but, with the exception of one assay, excellent correlation with ID-LC/tandem MS. Recalibration of the immunoassay results considerably reduced the between-assay variation. Moreover, after recalibration, 3 of the 4 assays fulfilled the total error specification of 32% proposed by the ADA Workgroup. Conclusions: Recalibration of insulin assays by regression equations established from method comparison with ID-LC/tandem MS can result in successful standardization and fulfillment of the total error criterion proposed by the ADA Workgroup.

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IFCC international conventional reference procedure for the measurement of free thyroxine in serum

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm.2011.639 ◽

2011 ◽

Vol 49 (8) ◽

Cited By ~ 19

Author(s):

Sofie K. Van Houcke ◽

Katleen Van Uytfanghe ◽

Eri Shimizu ◽

Wataru Tani ◽

Masao Umemoto ◽

...

Keyword(s):

Equilibrium Dialysis ◽

Free Thyroxine ◽

Regenerated Cellulose ◽

Tandem Ms ◽

Thyroid Function Tests ◽

Thermostatic Control ◽

Reference Procedure ◽

Amount Of Substance ◽

Calibration Measurement ◽

Lc Tandem Ms

AbstractThe IFCC Working Group for Standardization of Thyroid Function Tests proposes a candidate international conventional reference procedure (RMP) for measurement of the amount-of-substance concentration of free thyroxine in plasma/serum at physiological pH 7.40 and temperature (37.0°C). The unit for reporting measurement results is, by convention, pmol/L. The RMP is based on equilibrium dialysis isotope dilution-liquid chromatography/tandem mass spectrometry (ED-ID-LC/tandem MS). The rationale for proposing a conventional RMP is that, because of the physical separation step, it is unknown whether the measurement truly reflects the concentration of free thyroxine (FT4) in serum. Therefore, the ED part of the RMP has to strictly adhere to the following conditions: use of a dialysis buffer with a biochemical composition resembling the ionic environment of serum/plasma as closely as possible; buffering of the sample to a pH of 7.40 (at 37.0°C) before dialysis, however, without additional dilution; dialysis in a device with a dialysand/dialysate compartment of identical volume and separated by a membrane of regenerated cellulose and adequate cut-off; thermostatic control of the temperature during dialysis at 37.0°C±0.50°C. The convention does not apply to the ID-LC/tandem MS part, provided it is eligible to be nominated for review by the Joint Committee for Traceability in Laboratory Medicine. Here, we describe the ED procedure, inclusive its validation and transferability, in greater detail. We recommend a protocol for successful calibration, measurement and monitoring of the accuracy/trueness and precision of the candidate conventional RMP. For details on our ID-LC/tandem MS procedures, we refer to the Supplement.

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Sequence Mapping of Epoxide Adducts in Human Hemoglobin with LC−Tandem MS and the Salsa Algorithm

Chemical Research in Toxicology ◽

10.1021/tx015589+ ◽

2002 ◽

Vol 15 (6) ◽

pp. 799-805 ◽

Cited By ~ 26

Author(s):

Hamid Badghisi ◽

Daniel C. Liebler

Keyword(s):

Tandem Ms ◽

Human Hemoglobin ◽

Sequence Mapping ◽

Lc Tandem Ms

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Perspective on Advancing FDA Regulatory Monitoring for Mycotoxins in Foods using Liquid Chromatography and Mass Spectrometry (Review)

Journal of AOAC International ◽

10.5740/jaoacint.16-0116 ◽

2016 ◽

Vol 99 (4) ◽

pp. 890-894 ◽

Cited By ~ 11

Author(s):

Kai Zhang ◽

Jon W Wong ◽

Alexander J Krynitsky ◽

Mary W Trucksess

Keyword(s):

Mass Spectrometry ◽

Liquid Chromatography ◽

Food Safety ◽

High Resolution ◽

Drug Administration ◽

Matrix Effects ◽

Tandem Ms ◽

Mycotoxin Analysis ◽

Lc Tandem Ms ◽

The U.S

Abstract The presence of mycotoxins (such as aflatoxins, deoxynivalenol, fumonisins, and patulin) is routinely monitored by the U.S. Food and Drug Administration (FDA) to ensure that their concentrations in food are below the levels requiring regulatory action or advisories. To improve the efficiency of mycotoxin analysis, the researchers at the FDA's Center for Food Safety and Applied Nutrition have been evaluating modern LC-MS technologies. Consequently, a variety of LC–tandem MS and LC–high-resolution MS methods have been developed, which simultaneously identify and quantitate multiple mycotoxins in foods and feeds. Although matrix effects (matrix-induced ion suppression or enhancement) associated with LC-MS-based mycotoxin analysis remain, this review discusses methods for managing these effects and proposes practical solutions for the future implementation of LC-MS-based multimycotoxin analysis.

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