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

2004 ◽  
Vol 2 (5) ◽  
pp. 783 ◽  
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

LC tandem MS – overview of technology

Pathology ◽  
2011 ◽  
Vol 43 ◽  
pp. S19
Author(s):  
James Pitt
Keyword(s):  
Tandem Ms ◽  
Lc Tandem Ms

LC-tandem MS workshop updates on latest developments and applications

2006 ◽  
Vol 25 (11) ◽  
pp. 1043-1044
Author(s):  
Damià Barceló ◽  
Mira Petrovic
Keyword(s):  
Tandem Ms ◽  
Lc Tandem Ms

Quantitation and Confirmation of Chloramphenicol, Florfenicol, and Nitrofuran Metabolites in Honey Using LC-MS/MS

2018 ◽  
Vol 101 (3) ◽  
pp. 897-903 ◽  
Author(s):  
Brian T Veach ◽  
Renea Anglin ◽  
Thilak K Mudalige ◽  
Paula J Barnes
Keyword(s):  
Extraction Procedure ◽  
Extraction Methods ◽  
Liquid Extraction ◽  
Tandem Ms ◽  
Robust Method ◽  
Calibration Standards ◽  
Single Extraction ◽  
Liquid Liquid Extraction ◽  
Lc Tandem Ms ◽  
Nitrofuran Metabolites

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%.

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

2007 ◽  
Vol 53 (8) ◽  
pp. 1462-1469 ◽  
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.

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

2011 ◽  
Vol 49 (8) ◽  
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.

Direct Analysis of Elastomer Compounds by Soft Ionization, Tandem (MS/MS) and High Resolution (AC-MS) Mass Spectrometry

1995 ◽  
Vol 68 (5) ◽  
pp. 783-793 ◽  
Author(s):  
Robert P. Lattimer
Keyword(s):  
Mass Spectrometry ◽  
Thermoplastic Polyurethane ◽  
High Sensitivity ◽  
High Specificity ◽  
Mass Spectrometric ◽  
Spectrometric Analysis ◽  
Tandem Ms ◽  
Organic Additives ◽  
Soft Ionization ◽  
Modern Mass

Abstract In recent years very effective mass spectrometric methods have been developed for direct polymer compound analysis. The high sensitivity, high specificity, and superb mixture analysis capabilities of modern mass spectrometry make it an invaluable tool in the polymer industry, particularly for qualitative analysis (chemical identification) of organic additives as well as polymeric components. “Survey” mass spectra obtained with soft ionization methods — field ionization (FI-MS) and chemical ionization (CI-MS) — provide diagnostic overviews of chemical composition. The supplemental tandem (MS/MS) and atomic composition (AC-MS) techniques are used to make specific identifications of various organic ingredients. This report describes the direct mass spectrometric analysis of three different elastomer compounds. Organic additives, including curatives, were identified via thermal desorption methods in a commercial EPDM bearing as well as a diene rubber V-belt. The composition of a commercial thermoplastic polyurethane was determined via pyrolysis (Py-CI-MS). These problem-solving examples illustrate the very effective role that mass spectrometry can play in the industrial polymer analysis laboratory.

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