Quantitative Analysis Of Cholesterol Research Articles

Metal Nanoparticles Based Electrochemical Biosensors for Cholesterol

Electrochemical biosensors (EBS) have recently gained much attention in the field of health care for the management of cholesterol (CHO). This review comprises a report on the modification of electrode surfaces with metal nanoparticles (MNP) for selective and sensitive sensing of CHO. Quantitative analysis of cholesterol is carried out with the use of the amperometric data of linear calibration plot. A good synergistic between MNP of working electrode (WE) and CHO give fast electron transfer and precised electrochemical detection of CHL.

Sensitive determination of cholesterol and its metabolic steroid hormones by UHPLC-MS/MS via derivatization coupled with dual ultrasonic-assisted dispersive liquid-liquid microextraction.

Quantitative analysis of cholesterol and its metabolic steroid hormones plays a vital role in diagnosing endocrine disorders and understanding disease progression, as well as in clinical medicine studies. Because of their extremely low abundance in body fluids, it remains a challenging task to develop a sensitive detection method. A hyphenated technique of dual ultrasonic-assisted dispersive liquid-liquid microextraction (dual-UADLLME) coupled with microwave-assisted derivatization (MAD) was proposed for cleansing, enrichment and sensitivity enhancement. 4'-Carboxy-substituted rosamine (CSR) was synthesized and used as derivatization reagent. An ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was developed for determination of cholesterol and its metabolic steroid hormones in the multiple reaction monitoring mode. Parameters of dual-UADLLME, MAD and UHPLC-MS/MS were all optimized. Satisfactory linearity, recovery, repeatability, accuracy and precision, absence of matrix effect and extremely low limits of detection (LODs, 0.08-0.15pgmL(-1) ) were achieved. Through the combination of dual-UADLLME and MAD, a determination method for cholesterol and its metabolic steroid hormones in human plasma, serum and urine samples was developed and validated with high sensitivity, selectivity, accuracy and perfect matrix effect results. Copyright © 2016 John Wiley & Sons, Ltd.

Cholesterol homeostasis in cardiovascular disease and recent advances in measuring cholesterol signatures

Despite the biochemical importance of cholesterol, its abnormal metabolism has serious cellular consequences that lead to endocrine disorders such as cardiovascular disease (CVD). Nevertheless, the impact of blood cholesterol as a CVD risk factor is still debated, and treatment with cholesterol-lowering drugs remains controversial, particularly in older patients. Although, the prevalence of CVD increases with age, the underlying mechanisms for this phenomenon are not well understood, and metabolic changes have not been confirmed as predisposing factors of atherogenesis. The quantification of circulating biomarkers for cholesterol homeostasis is therefore warranted, and reference values for cholesterol absorption and synthesis should be determined in order to establish CVD risk factors. The traditional lipid profile is often derived rather than directly measured and lacks a universal standard to interpret the results. In contrast, mass spectrometry-based cholesterol profiling can accurately measure free cholesterol as a biologically active component. This approach allows to detect alterations in various metabolic pathways that control cholesterol homeostasis, by quantitative analysis of cholesterol and its precursors/metabolites as well as dietary sterols. An overview of the mechanism of cholesterol homeostasis under different physiological conditions may help to identify predictive biomarkers of concomitant atherosclerosis and conventional CVD risk factors.

An Accurate Method for Cholesterol Analysis in Bile

An accurate method for quantitative analysis of cholesterol in human bile is presented. Bile cholesterol was extracted in a single solvent (chloroform) in single step and 1H NMR spectra of the extract were obtained by suppressing chloroform signal by presaturation. Cholesterol was quantitatively estimated through integral area of its H‐18 methyl signal which invariably appears distinctly in the nuclear magnetic resonance (NMR) spectrum. Precision and accuracy were determined from the recovery of added cholesterol from bile. Excellent correlation was observed between added and recovered cholesterol (R2=1). Direct and accurate analysis of cholesterol following simple extraction method as presented here may have important implications.

Cholesterol quantitation by GLC: artifactual formation of short-chain steryl esters.

A simple and rapid method for the quantitation of total cholesterol in lipid extracts using gas-liquid chromatography is presented here as a modification of an earlier saponification procedure (Ishikawa, T. T., J. MacGee, J. A. Morrison, and C. J. Glueck. 1974. Quantitative analysis of cholesterol in 5 to 20 microliters of plasma. J. Lipid Res. 15: 286-291). Using the original method, as well as a slightly modified version, we found a systematic loss of cholesterol measured as total cholesterol that was attributable to the formation of a byproduct during the procedure. Depending on the nature of the solvent mixture used for extraction after saponification, different byproducts were produced that had longer retention times than cholesterol. The byproducts were identified as cholesteryl butyrate (produced when methyl butyrate was included in the solvent mix) and cholesteryl propionate (with ethyl propionate in the solvent mix) by comparison to authentic standards using gas chromatography-mass spectroscopy. Using mixtures of cholesterol standards, we compared several solvents in lieu of the solvent mixture used in the original extraction procedure to identify those that eliminate the formation of the byproducts. Our optimized microsaponification procedure uses a single solvent, tetrachloroethylene, to extract lipids after the saponification reaction, and improves the accuracy of the cholesterol determination.

Analytical reviews in clinical biochemistry: the quantitative analysis of cholesterol.

Analytical reviews in clinical biochemistry: the quantitative analysis of cholesterol.

Quantitative analysis of cholesterol in 5 to 20 μl of plasma

A gas–liquid chromatographic micromethod for quantitation of cholesterol in 20 μl of plasma was developed using 5α-cholestane as an internal standard, saponification with tetramethylammonium hydroxide–isopropanol, and extraction with tetrachloroethylene–methyl butyrate. Cholesterol levels in plasma samples were calculated by comparing cholesterol–cholestane peak height ratios with those of preassayed reference plasma. Over a plasma cholesterol range of 44 to 468 mg/100 ml, the gas–liquid chromatographic micromethod and the automated ferric chloride colorimetric method gave nearly identical results (r = 0.99) in duplicate aliquots of 131 plasma samples.