scholarly journals Establishing pre-analytical requirements and maximizing peptide recovery in the analytical phase for mass spectrometric quantification of amyloid-β peptides 1–42 and 1–40 in CSF

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lauren M. Forgrave ◽  
J. Grace van der Gugten ◽  
Quyen Nguyen ◽  
Mari L. DeMarco
Keyword(s):  
Mass Spectrometry ◽  
Clinical Laboratory ◽  
Comprehensive Evaluation ◽  
Solid Phase ◽  
Amyloid Β ◽  
Careful Consideration ◽  
Mass Spectrometric ◽  
Analytical Sensitivity ◽  
Surrogate Matrix ◽  
Analytical Phase

Abstract Objectives Amyloid-β (Aβ) peptides in cerebrospinal fluid (CSF), including Aβ42 (residues 1–42) and Aβ40 (residues 1–40), are utilized as biomarkers in the diagnostic workup of Alzheimer’s disease. Careful consideration has been given to the pre-analytical and analytical factors associated with measurement of these peptides via immunoassays; however, far less information is available for mass spectrometric methods. As such, we performed a comprehensive evaluation of pre-analytical and analytical factors specific to Aβ quantification using mass spectrometry. Methods Using our quantitative mass spectrometry assay for Aβ42 and Aβ40 in CSF, we investigated the potential for interference from hemolysate, bilirubin, lipids, and anti-Aβ-antibodies. We also optimized the composition of the calibrator surrogate matrix and Aβ recovery during and after solid phase extraction (SPE). Results There was no interreference observed with total protein up to 12 g/L, hemolysate up to 10% (v/v), bilirubin up to 0.5% (v/v), intralipid up to 1% (v/v), or anti-Aβ-antibodies at expected therapeutic concentrations. For hemolysate, bilirubin and lipids, visual CSF contamination thresholds were established. In the analytical phase, Aβ recovery was increased by ∼50% via SPE solvent modifications and by over 150% via modification of the SPE collection plate, which also extended analyte stability in the autosampler. Conclusions Attention to mass spectrometric-specific pre-analytical and analytical considerations improved analytical sensitivity and reproducibility, as well as, established CSF specimen acceptance and rejection criteria for use by the clinical laboratory.

scholarly journals IDENTIFICATION OF CANNABIMIMETIC MDMB(N)-073F METABOLITES IN URINE BY METHOD OF GAS CHROMATOGRAPHY WITH MASS SPECTROMETRIC DETECTION

2019 ◽  
Vol 7 (2) ◽  
pp. 70-83 ◽  
Author(s):  
S. S. Kataev ◽  
O. N. Dvorskaya ◽  
M. A. Gofenberg
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Acute Poisoning ◽  
Mass Spectrometric ◽  
Mass Spectrometric Detection ◽  
Urine Samples ◽  
Instrumental Method ◽  
Phase Extraction

Background. At the beginning of 2019, the use of a new representative of synthetic cannabimimetics of the methylbutanoate indazole carboxamides group, MDMB(N)-073F, was recorded in a number of regions in the Russian Federation. Characteristic features of the pharmacological effect, the clinical picture of MDMB(N)-073F poisoning have not been studied, the psychoactive effects produced by MDMB(N)-073F remain unexplored. In this regard, the study of the new cannabimimetic metabolism is an important aspect in establishing the fact of taking MDMB(N)-073F during expert studies of biological objects.The aim of the research is identifying metabolites of synthetic MDMB(N)-73F cannabimimetics in real urine samples using solid-phase extraction (SPE) and gas chromatography (GC) with mass spectrometric detection (GC-MS).Materials and methods. 10 urine samples were collected from March 15 to March 29, 2019. 8 urine samples were taken from the medical examination offices of the city of Yekaterinburg and the Sverdlovsk region from the persons examined for intoxication; 2 urine samples were obtained from the patients of the Sverdlovsk regional center of acute poisoning upon enrolment to the toxic-intensive care unit with a preliminary diagnosis of “acute poisoning by synthetic cannabimimetics”. In the research, SampliQ EVIDEX-200 mg – 3 ml (Agilent, USA) cartridges were used for the sample preparation; β-glucuronidase Type HP-2, From Helix Pomatia, 100000 U/ml (Sigma-ALDRICH CHEMI, Germany) was used for enzymatic hydrolysis. Gas chromatography – mass spectrometry with the use of Agilent 7820 gas chromatograph with Agilent 5975 mass selective detector (Agilent, USA) was used as an instrumental method of the analysis.Results. The metabolites that make it possible to establish the fact of taking MDMB(N)-073F cannabimimetics via urine screening procedure to detect the presence of narcotic and medicinal substances with the use of solid-phase extraction and gas chromatography methods with mass spectrometry, have been described. The major metabolites MDMB(N)-073F in the urine of smoking mixtures consumers have been identified. The metabolism of MDMB(N)-073F has been found to be mainly due to hydrolysis of the ester group, hydroxylation, oxidative defluorination and N-dealkylation. Most of the resulting metabolites are excreted in the urine in the conjugated form.Conclusion. Gas chromatographic and mass spectrometric characteristics of some derivatives of the main metabolites of the new synthetic MDMB(N)-073F cannabimimetic have been obtained. This data can be used in the practice of forensic chemical and chemical toxicological analysis.

Quantitative detection of amyloid-β peptides by mass spectrometry: state of the art and clinical applications

2015 ◽  
Vol 53 (10) ◽  
Author(s):  
Pauline Bros ◽  
Vincent Delatour ◽  
Jérôme Vialaret ◽  
Béatrice Lalere ◽  
Nicolas Barthelemy ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amyloid Β ◽  
Clinical Applications ◽  
Health Concern ◽  
Quantitative Detection ◽  
Csf Biomarkers ◽  
Aβ Peptides ◽  
The Past ◽  
Analytical Phase ◽  
Interesting Alternative

AbstractAlzheimer’s disease (AD) is the most common form of dementia in humans, and a major public health concern with 35 million of patients worldwide. Cerebrospinal fluid (CSF) biomarkers being early diagnostic indicators of AD, it is essential to use the most efficient analytical methods to detect and quantify them accurately. These biomarkers, and more specifically amyloid-β (Aβ) peptides, are measured in routine clinical practice using immunoassays. However, there are several limits to this immunodetection in terms of specificity and multiplexing of the multiple isoforms of the Aβ peptides. To overcome these issues, the quantification of these analytes by mass spectrometry (MS) represents an interesting alternative, and several assays have been described over the past years. This article reviews the different Aβ peptides quantitative MS-based approaches published so far, compares their pre-analytical phase, and the different quantitative strategies implemented that might be suitable for clinical applications.

scholarly journals Plasma Free Metanephrine Measurement Using Automated Online Solid-Phase Extraction HPLC–Tandem Mass Spectrometry

2007 ◽  
Vol 53 (9) ◽  
pp. 1684-1693 ◽  
Author(s):  
Wilhelmina HA de Jong ◽  
Kendon S Graham ◽  
Jan C van der Molen ◽  
Thera P Links ◽  
Michael R Morris ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Mass Spectrometric ◽  
Mass Spectrometric Detection ◽  
Tandem Mass ◽  
Phase Extraction ◽  
Analytical Sensitivity ◽  
Automated Method ◽  
Online Solid Phase Extraction ◽  
Tandem Mass Spectrometric

Abstract Background: Quantification of plasma free metanephrine (MN) and normetanephrine (NMN) is considered to be the most accurate test for the clinical chemical diagnosis of pheochromocytoma and follow-up of pheochromocytoma patients. Current methods involve laborious, time-consuming, offline sample preparation, coupled with relatively nonspecific detection. Our aim was to develop a rapid, sensitive, and highly selective automated method for plasma free MNs in the nanomole per liter range. Methods: We used online solid-phase extraction coupled with HPLC-tandem mass spectrometric detection (XLC-MS/MS). Fifty microliters plasma equivalent was prepurified by automated online solid-phase extraction, using weak cation exchange cartridges. Chromatographic separation of the analytes and deuterated analogs was achieved by hydrophilic interaction chromatography. Mass spectrometric detection was performed in the multiple reaction monitoring mode using a quadrupole tandem mass spectrometer in positive electrospray ionization mode. Results: Total run-time including sample cleanup was 8 min. Intra- and interassay analytical variation (CV) varied from 2.0% to 4.7% and 1.6% to 13.5%, respectively, whereas biological intra- and interday variation ranged from 9.4% to 45.0% and 8.4% to 23.2%. Linearity in the 0 to 20 nmol/L calibration range was excellent (R2 > 0.99). For all compounds, recoveries ranged from 74.5% to 99.6%, and detection limits were <0.10 nmol/L. Reference intervals for 120 healthy adults were 0.07 to 0.33 nmol/L (MN), 0.23 to 1.07 nmol/L (NMN), and <0.17 nmol/L (3-methoxytyramine). Conclusions: This automated high-throughput XLC-MS/MS method for the measurement of plasma free MNs is precise and linear, with short analysis time and low variable costs. The method is attractive for routine diagnosis of pheochromocytoma because of its high analytical sensitivity, the analytical power of MS/MS, and the high diagnostic accuracy of free MNs.

scholarly journals Analytical method applied for perfluororinated chemicals in water, sediment and fish by liquid chromatography with tandem mass spectrometry

2017 ◽  
Vol 33 (3) ◽  
Author(s):  
Hồng Anh Dương ◽  
Ngọc Thúy Nguyễn ◽  
Quang Phan Dinh ◽  
Tuyến Hữu Lê ◽  
Kim Thị Trương ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Solid Phase ◽  
Mass Spectrometric ◽  
Tandem Mass ◽  
Phase Extraction ◽  
Environmental Media ◽  
Mass Spectrometric Detector ◽  
Fish Samples ◽  
Tandem Mass Spectrometric

Abstract: 12 perfluororinated chemicals including perflourocarbocylic acids and perfluoroankyl sulfonates (containing C4 to C12)  in environmental media such as water, sediment and fish were deternined by liquid chromatography with tandem mass spectrometric detector (LC-MS/MS) using  weak anion exchange cartridge (WAX) in solid phase extraction for sample preparation.  The result of method validation showed that the recoveries of 12 PFCs for water and fish samples were in a range from 87 to 112% ( 4-17% CV)  and a range from  81 to125% (3-12% CV), respectively. The method was a reliable analysis for 10 PFCs compounds of sediment sample which recieved the recoveries in a range from 80 to121% (3-16% CV), except PFUdA and PFDoA. The detection limits of 12 PFCs were from 0.06 to 0.6 ng/L for water and from 0.01 to 0.06 ng/g for sediment and fish samples.  

scholarly journals Recommendations for the Generation, Quantification, Storage, and Handling of Peptides Used for Mass Spectrometry–Based Assays

2016 ◽  
Vol 62 (1) ◽  
pp. 48-69 ◽  
Author(s):  
Andrew N Hoofnagle ◽  
Jeffrey R Whiteaker ◽  
Steven A Carr ◽  
Eric Kuhn ◽  
Tao Liu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Clinical Care ◽  
Internal Standard ◽  
Mass Spectrometric ◽  
Protein Quantification ◽  
Analytical Sensitivity ◽  
Central Importance ◽  
Protein Mass ◽  
Clinical Laboratories ◽  
Protein Assays

Abstract BACKGROUND For many years, basic and clinical researchers have taken advantage of the analytical sensitivity and specificity afforded by mass spectrometry in the measurement of proteins. Clinical laboratories are now beginning to deploy these work flows as well. For assays that use proteolysis to generate peptides for protein quantification and characterization, synthetic stable isotope–labeled internal standard peptides are of central importance. No general recommendations are currently available surrounding the use of peptides in protein mass spectrometric assays. CONTENT The Clinical Proteomic Tumor Analysis Consortium of the National Cancer Institute has collaborated with clinical laboratorians, peptide manufacturers, metrologists, representatives of the pharmaceutical industry, and other professionals to develop a consensus set of recommendations for peptide procurement, characterization, storage, and handling, as well as approaches to the interpretation of the data generated by mass spectrometric protein assays. Additionally, the importance of carefully characterized reference materials—in particular, peptide standards for the improved concordance of amino acid analysis methods across the industry—is highlighted. The alignment of practices around the use of peptides and the transparency of sample preparation protocols should allow for the harmonization of peptide and protein quantification in research and clinical care.

Confounding contaminants in mass spectrometric reaction monitoring

2018 ◽  
Author(s):  
Gilian T. Thomas ◽  
Landon MacGillivray ◽  
Natalie L. Dean ◽  
Rhonda L. Stoddard ◽  
Lars Yunker ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometric ◽  
Negative Ion ◽  
Reaction Monitoring ◽  
Schlenk Flask ◽  
Dynamic Analyses ◽  
Rubber Septa ◽  
Negative Ion Mode ◽  
Mode A

<p>Reactions carried out in the presence of rubber septa run the risk of additives being leached out by the solvent. Normally, such species are present at low enough levels that they do not interfere with the reaction significantly. However, when studying reactions using sensitive methods such as mass spectrometry, the appearance of even trace amounts of material can confuse dynamic analyses of reactions. A wide variety of additives are present in rubber along with the polymer: antioxidants, dyes, detergent, and vulcanization agents, and these are all especially problematic in negative ion mode. A redesigned Schlenk flask for pressurized sample infusion (PSI) is presented as a means of practically eliminating the presence of contaminants during reaction analyses.</p>

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