scholarly journals Characterization and Quantification of Selenoprotein P: Challenges to Mass Spectrometry

2021 ◽  
Vol 22 (12) ◽  
pp. 6283
Author(s):  
Jérémy Lamarche ◽  
Luisa Ronga ◽  
Joanna Szpunar ◽  
Ryszard Lobinski
Keyword(s):  
Mass Spectrometry ◽  
State Of The Art ◽  
Animal Health ◽  
Primary Standard ◽  
Selenoprotein P ◽  
Primary Standards ◽  
Analytical Approaches ◽  
Careful Investigation ◽  
Accurate Quantification

Selenoprotein P (SELENOP) is an emerging marker of the nutritional status of selenium and of various diseases, however, its chemical characteristics still need to be investigated and methods for its accurate quantitation improved. SELENOP is unique among selenoproteins, as it contains multiple genetically encoded SeCys residues, whereas all the other characterized selenoproteins contain just one. SELENOP occurs in the form of multiple isoforms, truncated species and post-translationally modified variants which are relatively poorly characterized. The accurate quantification of SELENOP is contingent on the availability of specific primary standards and reference methods. Before recombinant SELENOP becomes available to be used as a primary standard, careful investigation of the characteristics of the SELENOP measured by electrospray MS and strict control of the recoveries at the various steps of the analytical procedures are strongly recommended. This review critically discusses the state-of-the-art of analytical approaches to the characterization and quantification of SELENOP. While immunoassays remain the standard for the determination of human and animal health status, because of their speed and simplicity, mass spectrometry techniques offer many attractive and complementary features that are highlighted and critically evaluated.

Determination of T-2 and HT-2 toxins in food and feed: an update

2014 ◽  
Vol 7 (2) ◽  
pp. 131-142 ◽  
Author(s):  
R. Krska ◽  
A. Malachova ◽  
F. Berthiller ◽  
H.P. van Egmond
Keyword(s):  
Mass Spectrometry ◽  
Matrix Effects ◽  
Certified Reference Materials ◽  
Animal Health ◽  
Rapid Screening ◽  
Chromatography Method ◽  
Food And Feed ◽  
Immunochemical Methods ◽  
Analytical Approaches

Based on the recent scientific opinion of the European Food Safety Authority (EFSA) Panel on Contaminants in the Food Chain on the risks to human and animal health related to the presence of T-2 and HT-2 toxins in food and feed that was published by EFSA in the EFSA Journal, this article provides an update on the determination of these Fusarium mycotoxins. After a brief introduction into the chemistry of these toxins, both chromatographic and immuno-analytical methods are discussed for the determination of these type A trichothecenes. During the last decade, liquid chromatography with (tandem) mass spectrometry has become the most frequently used method for the determination of T-2 and HT-2 toxins, often within a multi-analyte approach. However, complex matrices and the resulting signal suppression effects, as observed particularly in electrospray-mass spectrometry methods owing to matrix effects, may require careful optimisation of clean-up, usage of matrix matched standards, or e.g. the use of internal standards. For specific purposes where extremely low limits of quantification are needed, e.g. for the analysis of duplicate diets, a dedicated gas chromatography method with multistage mass spectrometry has become available. Other novel analytical approaches to determine T-2 and HT-2 toxins in food and feed include biosensor-based methods in surface plasmon resonance and electrochemical formats, as well as DNA microchip assays. For rapid screening, several immunochemical methods (mostly ELISAs) have become available and some are sold as commercial test kits. Whereas these methods work fast, cross-reactivities with other trichothecenes can have an undesired effect on their accuracy. While proficiency tests including T-2 and HT-2 toxins have been carried out, none of the chromatographic or immunochemical methods have been formally validated in interlaboratory validation studies. There are no certified reference materials available for T-2 and HT-2 toxins.

Automatic Flame Photometric Determination of Potassium in Fertilizers. A. Elimination of Anion Exchange Cleanup. B. Using Direct Available P2O5 Extract

1965 ◽  
Vol 48 (6) ◽  
pp. 1095-1100
Author(s):  
James P Ussary ◽  
Charles W Gehrke
Keyword(s):  
Anion Exchange ◽  
Primary Standard ◽  
Photometric Determination ◽  
Photometric Method ◽  
Potassium Salts ◽  
Commercial Fertilizer ◽  
Aoac Official ◽  
Primary Standards ◽  
Standard Grade

Abstract Three primary standard grade potassium salts, eight Magruder check samples, and 18 commercial fertilizer samples were analyzed by three methods. Primary standards gave an average recovery of 100.0% and an average range of 0.21% K20. Magruder check samples averaged 0.09% K20 higher by the modified flame photometric method than the grand averages of the STPB results on the respective Magruder reports. The modified flame photometric method averaged 0.02% K20 lower than the official flame photometric method and 0.11% K20 higher than the official STPB method on 18 commercial fertilizer samples. The automatic flame photometric method, without anion exchange cleanup, is rapid enough for routine analysis and is as accurate and precise as the AOAC official methods. The method was also applied to the direct available P205 extract. Results on three primary grade potassium salts, seven Magruder check samples, and 13 commercial fertilizer samples were as accurate and precise as the official STPB method.

scholarly journals HILIC-Enabled 13C Metabolomics Strategies: Comparing Quantitative Precision and Spectral Accuracy of QTOF High- and QQQ Low-Resolution Mass Spectrometry

Metabolites ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 63 ◽  
Author(s):  
André Feith ◽  
Attila Teleki ◽  
Michaela Graf ◽  
Lorenzo Favilli ◽  
Ralf Takors
Keyword(s):  
Mass Spectrometry ◽  
Isotope Dilution Mass Spectrometry ◽  
Absolute Quantification ◽  
Spectral Accuracy ◽  
Time Resolved ◽  
13C Tracer ◽  
Accurate Quantification ◽  
Tracer Experiments

Dynamic 13C-tracer-based flux analyses of in vivo reaction networks still require a continuous development of advanced quantification methods applying state-of-the-art mass spectrometry platforms. Utilizing alkaline HILIC chromatography, we adapt strategies for a systematic quantification study in non- and 13C-labeled multicomponent endogenous Corynebacterium glutamicum extracts by LC-QTOF high resolution (HRMS) and LC-QQQ tandem mass spectrometry (MS/MS). Without prior derivatization, a representative cross-section of 17 central carbon and anabolic key intermediates were analyzed with high selectivity and sensitivity under optimized ESI-MS settings. In column detection limits for the absolute quantification range were between 6.8–304.7 (QQQ) and 28.7–881.5 fmol (QTOF) with comparable linearities (3–5 orders of magnitude) and enhanced precision using QQQ-MRM detection. Tailor-made preparations of uniformly (U)13C-labeled cultivation extracts for isotope dilution mass spectrometry enabled the accurate quantification in complex sample matrices and extended linearities without effect on method parameters. Furthermore, evaluation of metabolite-specific m+1-to-m+0 ratios (ISR1:0) in non-labeled extracts exhibited sufficient methodical spectral accuracies with mean deviations of 3.89 ± 3.54% (QTOF) and 4.01 ± 3.01% (QQQ). Based on the excellent HILIC performance, conformity analysis of time-resolved isotopic enrichments in 13C-tracer experiments revealed sufficient spectral accuracy for QQQ-SIM detection. However, only QTOF-HRMS ensures determination of the full isotopologue space in complex matrices without mass interferences.

Determination of cortisol in hair using liquid chromatography-tandem mass spectrometry: a short review

Bioanalysis ◽  
2021 ◽  
Author(s):  
Daniella Rheingantz Decker Soares ◽  
Marina Venzon Antunes ◽  
Rafael Linden
Keyword(s):  
Mass Spectrometry ◽  
Short Review ◽  
Reversed Phase ◽  
Negative Ion ◽  
Stress Evaluation ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Negative Ion Mode ◽  
Analytical Approaches

Cortisol is considered a particularly relevant biomarker in the context of stress evaluation. This study aims to review of the available literature on the determination of cortisol in hair using LC-MS/MS. Currently, there is no standardized procedure for the measurement of cortisol concentrations in hair, and different sample preparation, chromatographic separation and mass spectrometric detection conditions were described. Simple methanolic extraction, reversed-phase separation and MRM detection in negative ion mode are the most common employed analytical approaches. Reported assays presented acceptable sensitivity for clinical purposes. The increasing use of mass spectrometry in clinical laboratories may contribute to the establishment of LC-MS/MS as the method of choice for the determination of cortisol concentrations in hair.

Determination of nivalenol in food and feed: an update

2014 ◽  
Vol 7 (3) ◽  
pp. 247-255 ◽  
Author(s):  
A. Malachova ◽  
H.P. van Egmond ◽  
F. Berthiller ◽  
R. Krska
Keyword(s):  
Animal Health ◽  
Direct Analysis ◽  
Fusarium Mycotoxin ◽  
Multi Stage ◽  
Health Related ◽  
Food And Feed ◽  
Interlaboratory Validation ◽  
Scientific Opinion ◽  
Accurate Quantification

Based on the recent scientific opinion published by the EFSA CONTAM panel on the risks to human and animal health related to the presence of nivalenol in food and feed, this article provides an update on the determination of this Fusarium mycotoxin. After a brief introduction into the chemistry of nivalenol, chromatographic methods as well as other approaches are being discussed. Methods for the determination of nivalenol are well established and can be applied for the analysis of cereals, food, feed and biological samples. Accurate quantification of nivalenol is mostly carried out by liquid chromatography coupled with (multi-stage) mass spectrometry (MS) often within a multi-analyte approach. Some novel techniques, such as direct analysis in real time (DART) MS and electrochemical methods, have shown potential to determine nivalenol, but applications for routine measurements are not yet available. None of the currently available analytical methods has been formally validated in interlaboratory validation studies. While a certified calibrant for nivalenol is available, no matrix reference materials have been developed. Due to the scarcity of appropriate antibodies also no rapid immunochemical methods specific for nivalenol have become available.

scholarly journals Πρωτεωμική ανάλυση βιολογικών δειγμάτων για την ανάδειξη βιοδεικτών του καρκίνου

2011 ◽  
Author(s):  
Θεόδωρος Ρουμελιώτης
Keyword(s):  
Mass Spectrometry ◽  
Blood Serum ◽  
Biological Samples ◽  
State Of The Art ◽  
Genetic Constitution ◽  
Major Public Health Problem ◽  
Pharmacological Response ◽  
Depth Analysis ◽  
Potential Biomarkers

The various forms of cancer is a major public health problem of the modern societies. Several environmental and genetic factors have been recognized to be responsible for the occurrence of cancer and key biological mechanisms involved have been revealed as well. However, early diagnosis, prognosis of progression and the identification of pharmacological therapeutic targets remain partially ineffective fields in clinical practice despite the fact that studies focusing on these areas are increasing rapidly. This is largely due to the complexity and diversity of both the disease and the genetic constitution of individuals and hence of the biological samples. Therefore, the main characteristics that an experimental approach should concentrate in order to provide solutions to such questions should be, holisticity, accuracy, sensitivity, cross-verification and the use of well-characterized biological samples. State of the art proteomics based on mass spectrometry is a useful tool for the first step in this direction which is the identification of potential biomarkers which then should be tested for their sensitivity and specificity using simple and validated biochemical techniques in inter-laboratory assays. This study, presents novel applications of combined state of the art proteomic techniques for the in-depth analysis and characterization of biological specimens such as tissue and blood serum for the determination of potential biomarkers of diagnosis, prognosis and pharmacological response for breast cancer and prostate cancer as well. The analysis of biological samples was based on the principles of multidimensional liquid chromatography combined with tandem mass spectrometry. The study resulted in the qualitative and semi-quantitative determination of a large number of proteins that extensively covers the proteome of tissues from breast biopsies and blood serum compared with the data available in current bibliography. Finally, proteins with differences in expression between the different biological states studied were identified with potential in diagnosis, prognosis and pharmacological response that consist innovative findings amenable to further study.

scholarly journals Determination of alkyl amines in atmospheric aerosol particles: a comparison of gas chromatography-mass spectrometry and ion chromatography approaches

2014 ◽  
Vol 7 (3) ◽  
pp. 2127-2152 ◽  
Author(s):  
R.-J. Huang ◽  
W.-B. Li ◽  
Y.-R. Wang ◽  
Q. Y. Wang ◽  
K.-F. Ho ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Ion Chromatography ◽  
Aerosol Particles ◽  
Gas Chromatography Mass Spectrometry ◽  
Limits Of Detection ◽  
Alkyl Amines ◽  
Chromatography Mass Spectrometry ◽  
Analytical Approaches

Abstract. In recent years low molecular weight alkyl amines have been recognized to play an important role in particle formation and growth in the lower atmosphere. However, major uncertainties are associated with their atmospheric processes, sources and sinks, mostly due to the lack of ambient measurements and the difficulties in accurate quantification of alkyl amines at trace level. In this study, we present the evaluation and optimization of two analytical approaches, i.e., gas chromatography-mass spectrometry (GC-MS) and ion chromatography (IC), for the determination of alkyl amines in aerosol particles. Alkyl amines were converted to carbamates through derivatization with isobutyl chloroformate for GC-MS determination. A set of parameters affecting the analytical performances of the GC-MS approach, including reagent amount, reaction time and pH value, was evaluated and optimized. The accuracy is 84.3–99.1%, and the limits of detection obtained are 1.8–3.9 pg. For the IC approach, a solid phase extraction (SPE) column was used to separate alkyl amines from interfering cations before IC analysis. 1–2% (v/v) of acetone (or 2–4% (v/v) of acetonitrile) was added to the eluent to improve the separation of alkyl amines on the IC column. The limits of detection obtained are 2.1–15.9 ng and the accuracy is 55.1–103.4%. The lower accuracy can be attributed to evaporation losses of amines during the sample concentration procedure. Measurements of ambient aerosol particle samples collected in Hong Kong show that the GC-MS approach is superior to the IC approach for the quantification of primary and secondary alkyl amines due to its lower detection limits and higher accuracy.

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