Determination of non-cholesterol sterols in serum and HDL fraction by LC/MS-ms: Significance of matrix-related interferences

Summary Background Non-cholesterol sterols (NCS) are promising biomarkers for estimation of cholesterol homeostasis properties. In addition, determination of NCS in high-density lipoprotein (HDL) fraction (HDL-NCS) could provide information on cholesterol efflux. However, matrix effects interfere in liquid chromatography–mass spectrometry (LC-MS) analysis of NCS, thereby impairing the method sensitivity. The aims of this study were development, optimization and validation of LC-MS method for quantification of NCS in serum and HDL-NCS. Additionally, matrix effect interferences and methods application in individual serum samples were examined. Methods HDL precipitating reagent was used for HDL isolation. Matrix effect was examined by comparing different surrogates by simple regression analysis. Validation was conducted according to the FDA-ICH guideline. 20 healthy volunteers were recruited for testing of method application. Results The observed matrix effect was 30%, and matrix comparison showed that cholesterol was the dominant contributor to the matrix effect. Cholesterol concentration was adjusted by construction of the calibration curve for serum and HDL fraction (5 mmol/L and 2.5 mmol/L, respectively). The intra- and inter- run variabilities for NCSs were 4.7–10.3% for serum NCS and 3.6–13.6% for HDL-NCS and 4.6–9.5% for serum NCSs and 2.5–9.8% for HDL-NCS, respectively. Recovery studies showed satisfactory results for NCSs: 89.8–113.1% for serum NCS and 85.3–95.8% for HDL-NCS. Conclusions The method was successfully developed and optimized. The matrix interference was solved by customising calibration curves for each method and sample type. The measurement of NCS in HDL fraction was proposed for the first time as potentially useful procedure in biomedical researches.

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Determination of Arsenic, Chromium and Lead in titanium dioxide pigments by ICP- OES with Concomitant Metals Analyser

International Journal of Scientific Research in Science and Technology ◽

10.32628/ijsrst196664 ◽

2019 ◽

pp. 296-305

Author(s):

Beena Sunilkumar ◽

S. B. Singh

Keyword(s):

Titanium Dioxide ◽

Matrix Effects ◽

Mineral Acid ◽

Icp Oes ◽

Acid Decomposition ◽

Simple Method ◽

Sample Dissolution ◽

The Matrix ◽

Generating System

A simple method has been developed for the determination of trace toxic elements like arsenic, lead and chromium in titanium dioxide pigment samples by ICP OES attached with a Concomitant Metals Analyser. Open mineral acid decomposition was used for sample dissolution employing a mixture of nitric and hydrofluoric acids. The continuous online generation of hydrides into the plasma was achieved through a concomitant metals analyser. The recovery of arsenic, lead and chromium and the matrix effects of titanium on these elements have been studied with spiking experiments. The proposed method has been successfully applied to the determination of arsenic and other elements in titanium pigment samples. The continuous hydride generating system, Concomitant Metals Analyser (CMA) improved the sensitivity of analysis nearly five times in pigment samples. The precision of the measurements was found to be less than 10% RSD.

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Direct Fluorometric Determination of Total Cholesterol in Serum Using Derivatized Cholesterol Oxidase

Applied Spectroscopy ◽

10.1366/0003702001950968 ◽

2000 ◽

Vol 54 (8) ◽

pp. 1157-1162 ◽

Cited By ~ 10

Author(s):

Javier Galbán ◽

José F. Sierra ◽

José M. López Sebastian ◽

Susana de Marcos ◽

Juan R. Castillo

Keyword(s):

Blood Serum ◽

Total Cholesterol ◽

Cholesterol Oxidase ◽

Enzymatic Reaction ◽

Direct Determination ◽

Analytical Signal ◽

Cholesterol Concentration ◽

Serum Samples ◽

Response Range

In this paper the use of cholesterol oxidase derivatized with a fluorescein derivative is proposed for the direct determination of total cholesterol in blood serum. The method is based on the changes in the fluorescence of the solution during the enzymatic reaction (λexe = 498 nm and λem 519 nm). A mathematical model which relates the analytical signal to the total cholesterol concentration was developed, and the model can also be used to obtain some of the thermodynamic constants of the process. The method has a linear response range up to 70 mg/L of cholesterol, a detection limit of 2.5 mg/L, and the precision was 1.0% (40 mg/L cholesterol, n = 10). The method was applied to total cholesterol determination in blood serum samples. The results were compared to those obtained by a commercial analyzer, and statistically similar results were obtained. The use of derivatized cholesterol oxidase makes it possible to simplify the methodology normally used in this type of determination (the indicator reaction is avoided and the number of reagents reduced), with the added advantage that the analytical signal is independent of the concentrations of O2 and cholesterol oxidase.

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Comparison of the Du Pont aca and Dow methods for determination of high-density lipoprotein cholesterol.

Clinical Chemistry ◽

10.1093/clinchem/30.1.127 ◽

1984 ◽

Vol 30 (1) ◽

pp. 127-129 ◽

Cited By ~ 4

Author(s):

N N Rehak ◽

R J Elin ◽

R Chesler ◽

E Johnson

Keyword(s):

High Density Lipoprotein ◽

Disease Control ◽

Total Cholesterol ◽

High Density Lipoprotein Cholesterol ◽

Dextran Sulfate ◽

Density Lipoprotein ◽

High Density ◽

Lipoprotein Cholesterol ◽

Serum Samples

Abstract We compared the Du Pont aca (phosphotungstate-enzymic cholesterol) and the Dow (dextran sulfate/Mg2+-enzymic cholesterol) methods for the determination of high-density lipoprotein cholesterol (HDLC) and total cholesterol in serum from 113 patients. The aca results for both total cholesterol and HDLC were significantly greater (p less than 0.0001) than the Dow results, the aca method overestimating the HDLC concentration (mean recovery 107.2% in serum samples with values assigned by the Centers for Disease Control). The precision of the aca method for HDLC was essentially the same as that of the Dow method. Bilirubin (up to 0.17 g/L), hemoglobin (up to 4 g/L), and slight lipemia (triglycerides up to 5.4 g/L) did not interfere with the aca method.

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Evaluation of multiple solid-phase microextraction as a technique to remove the matrix effect in packaging analysis for determination of volatile organic compounds

Journal of Chromatography A ◽

10.1016/j.chroma.2003.08.066 ◽

2003 ◽

Vol 1020 (2) ◽

pp. 189-197 ◽

Cited By ~ 27

Author(s):

Óscar Ezquerro ◽

Begoña Pons ◽

Marı́a Teresa Tena

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Matrix Effect ◽

Solid Phase Microextraction ◽

Solid Phase ◽

Volatile Organic ◽

The Matrix

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Determination of Opiates in Whole Blood and Vitreous Humor: A Study of the Matrix Effect and an Experimental Design to Optimize Conditions for the Enzymatic Hydrolysis of Glucuronides

Journal of Analytical Toxicology ◽

10.1093/jat/bks007 ◽

2012 ◽

Vol 36 (3) ◽

pp. 162-170 ◽

Cited By ~ 18

Author(s):

L. R. Sanches ◽

S. C. Seulin ◽

V. Leyton ◽

B. A. P. Bismara Paranhos ◽

C. A. Pasqualucci ◽

...

Keyword(s):

Experimental Design ◽

Enzymatic Hydrolysis ◽

Matrix Effect ◽

Whole Blood ◽

Vitreous Humor ◽

The Matrix ◽

Hydrolysis Of

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Detection Confirmation and Determination of Trace Amounts of Selenium by X-Ray Methods

Advances in X-ray Analysis ◽

10.1154/s0376030800002792 ◽

1963 ◽

Vol 7 ◽

pp. 542-554

Author(s):

Frank L. Chan

Keyword(s):

Matrix Effects ◽

Hexagonal Structure ◽

Elemental Selenium ◽

X Ray Diffraction ◽

X Ray ◽

Yellow Color ◽

The Matrix ◽

Ray Methods ◽

Tetravalent State

AbstractRecently, interest in the determination of selenium in trace amounts has been greatly intensified because of the nutritional aspects of this element. It has been reported that selenium in the amount of 13 μg in the form of sodium selenite in 100 g of feed has an effect similar to that of vitamin E. In the field of semiconductors, the detection and determination of trace amounts of selenium in arsenic, antimony, and small single crystals of solid solution of cadmium selenide and sulfide are of considerable importance in semiconductor performance.In the Aerospace Research Laboratories, 4,5 diamino-6-tbiopyi-imidine has been successfully adopted as a reagent for the spectrophotometric determination of selenium. The reaction of 4,5 diamino-6-thiopyrimidine and tetxavalent selenium produces a yellow color with the formation of elemental selenium. It is possible to determine elemental selenium by collecting it in a thin layer. The selenium deposited in this layer may then be determined by an X-ray fluorescence method. A procedure of this nature has the advantage of eliminating the matrix effects commonly encountered in X-ray fluorescence. Furthermore, the slow generation of selenium affords a convenient means of detection and confirmation of this element by the use of X-ray diffraction procedures. By this technique selenium is first converted to its tetravalent state and is then reacted with 4,5 diamino-6-thiopyrimidine. On standing, the selenium is reduced to a red precipitate of elemental selenium which can be dissolved in carbon disulfide. Finally, the selenium can be converted into its hexagonal structure by annealing at 205-207°C.

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Analytical validation of eight methods of thyroglobulin measurement in fine-needle aspiration washouts

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/0004563220968369 ◽

2020 ◽

pp. 000456322096836

Author(s):

Florence Boux de Casson ◽

Rémi Beloeil ◽

Anne-Sophie Gauchez ◽

Charlotte Oris ◽

Monique Leban ◽

...

Keyword(s):

Matrix Effect ◽

Limit Of Detection ◽

Needle Aspiration ◽

Decision Threshold ◽

Serum Samples ◽

Cervical Lymph Nodes ◽

Analytical Error ◽

Low Concentrations ◽

The Matrix ◽

Assay Methods

Background Thyroglobulin (Tg) assay in washout fluids of fine needles, after cervical lymph nodes aspiration, is used for detecting metastases from differentiated thyroid carcinomas. Assay methods are the same as for Tg in serum. However, with non-serum samples, methods require extensive validation to notably check for the absence of matrix effect. This study fits this context. Our objectives were to assess analytic performances, in washout fluid, of eight different Tg assay methods and to compare them to validated data in serum. Methods Eleven medical laboratories participated in this study. The matrix tested was phosphate-buffer saline containing 1% bovine serum albumin (PBS-1% BSA). Samples used were dilutions, in this buffer, of Certified Reference Material (CRM 457). We verified, for all methods, the limit of detection, precision, linearity, trueness and accuracy. Results In PBS-1% BSA, the functional sensitivities (FS) were comparable to those expected for serum. All the methods were linear. The relative biases of trueness were between –24.5 and 10.2% around 1 µg/L. Total analytical error was ≤40% near the functional sensitivity values. Conclusion No quantitatively important matrix effect was observed. All the methods showed their ability to measure Tg in PBS-1% BSA, over the concentration range of interest, with acceptable total analytical error. We validated the functional sensitivity value as a decision threshold in thyroidectomized patients after treatment and with low concentrations of serum Tg.

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Implications of Matrix Effects in Quantitative HPLC/ESI-ToF-MS Analyses of Atmospheric Organic Aerosols

Proceedings ◽

10.3390/proceedings2020055006 ◽

2020 ◽

Vol 55 (1) ◽

pp. 6

Author(s):

Cornelia Amarandei ◽

Romeo Iulian Olariu ◽

Cecilia Arsene

Keyword(s):

Mass Spectrometry ◽

Electrospray Ionization ◽

Matrix Effect ◽

Matrix Effects ◽

Organic Aerosols ◽

Organic Chemical ◽

Ionization Mass ◽

Signal Suppression ◽

The Matrix ◽

Tof Ms

Matrix-induced signal suppression or enhancements are known phenomena in electrospray ionization mass spectrometry. Very few studies report on method development for organic aerosols analyses with the evaluation of the matrix effects. The matrix effects lead to errors in the quantification of the analytes and affect the detection capability, precision, and accuracy of an analysis method. The present study reports on the matrix effects in the analysis of organic chemical compounds present in atmospheric aerosol particles collected on quartz filters. A total number of 19 analytes, including different classes of organic compounds, such as monoaromatic phenols and derivatives (e.g., catechol, 4-methylcatechol, 3-methoxycatechol, 4-nitrocatechol, 4-nitrophenol, 2,4-dinitrophenol, 2,6-dimethyl-4-nitrophenol), carboxylic acids (terebic acid, adipic acid, pimelic acid, phthalic acid, vanillic acid), and sulfonic acids (e.g., camphor-10-sulfonic acid), was investigated by high-performance liquid chromatography coupled to electrospray ionization time-of-flight mass spectrometry (HPLC/ESI-ToF-MS). The HPLC and ESI set-up parameters used in this study were previously optimized for the investigated compounds. Different volumes of a standard mixture were added to sample extracts, with final solutions concentrations in the 50–1500 μg L−1 range. For the investigated concentration range, the observed matrix effect was independent of the standard concentration level. For quartz filter extracts, the average matrix effect determined on a concentration-based method was 109.5 ± 6.1%. Both signal suppression and enhancement effects were observed for different compounds. For other analytes, the influence of the matrix effect is variable, suggesting that the use of an internal standard is not sufficient for the matrix effects correction. Competition between analyte ions and matrix components in the gas-phase ionization processes occurring in electrospray might explain signal suppression while generated coeluted isobaric compounds might induce signal enhancement.

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