scholarly journals Stability of ascorbic acid in serum and plasma prior to analysis

2002 ◽  
Vol 39 (5) ◽  
pp. 518-520 ◽  
Author(s):  
Simon YL Ching ◽  
Alex W Prins ◽  
John P Beilby
Keyword(s):  
Ascorbic Acid ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Perchloric Acid ◽  
Healthy Subjects ◽  
High Performance ◽  
Minimum Loss ◽  
Blood Samples ◽  
The Stability

Introduction: The stability of ascorbic acid in serum and plasma prior to analysis was studied. Methods: Blood samples were collected from ten healthy subjects into Vacutainer tubes containing either dipotassium EDTA, lithium-heparin or no additive. Ascorbic acid was analysed following immediate separation and preservation of samples, following delayed separation for 2 h and after delayed deproteinization and preservation for 2, 5 and 8 h. Deproteinization and preservation were achieved using a solution containing perchloric acid, EDTA and dithiothreitol. Ascorbic acid was analysed by high-performance liquid chromatography. Results: Blood collected into EDTA and separated, deproteinized and preserved immediately gave the highest yield of ascorbic acid. Loss of analyte after delayed separation was least for EDTA tubes (median 7%, range 4-13%), followed by lithium-heparin (median 18%, range 10-32%) and serum (median 26%, range 14-50%). Immediate separation of samples but delayed deproteinization and preservation also resulted in substantial losses of ascorbic acid. Conclusion: Minimum loss of ascorbic acid is achieved if blood is collected into tubes containing dipotassium EDTA and separated within 2 h, followed by immediate deproteinization and preservation.

scholarly journals Determination of 19 Psychoactive Substances in Premortem and Postmortem Whole Blood Samples Using Ultra-High-Performance Liquid Chromatography–Tandem Mass Spectrometry

Separations ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 78
Author(s):  
Sevasti Karampela ◽  
Jessica Smith ◽  
Irene Panderi
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Formic Acid ◽  
Whole Blood ◽  
High Performance ◽  
Tandem Mass ◽  
Psychoactive Substances ◽  
Blood Samples ◽  
Whole Blood Samples

An ever-increasing need exists within the forensic laboratories to develop analytical processes for the qualitative and quantitative determination of a broad spectrum of new psychoactive substances. Phenylethylamine derivatives are among the major classes of psychoactive substances available on the global market and include both amphetamine analogues and synthetic cathinones. In this work, an ultra-high-performance liquid chromatography-positive ion electrospray ionization tandem mass spectrometric method (UHPLC-ESI-MS/MS) has been developed and fully validated for the determination of 19 psychoactive substances, including nine amphetamine-type stimulants and 10 synthetic cathinone derivatives, in premortem and postmortem whole blood. The assay was based on the use of 1 mL premortem or postmortem whole blood, following solid phase extraction prior to the analysis. The separation was achieved on a Poroshell 120 EC-C18 analytical column with a gradient mobile phase of 0.1% formic acid in acetonitrile and 0.1% formic acid in water in 9 min. The dynamic multiple reaction monitoring used in this work allowed for limit of detection (LOD) and lower limit of quantitation (LOQ) values of 0.5 and 2 ng mL−1, respectively, for all analytes both in premortem and postmortem whole blood samples. A quadratic calibration model was used for the 12 quantitative analytes over the concentration range of 20–2000 ng mL−1, and the method was shown to be precise and accurate both in premortem and postmortem whole blood. The method was applied to the analysis of real cases and proved to be a valuable tool in forensic and clinical toxicology.

Determination of ascorbic acid in the retina during chicken embryo development using high performance liquid chromatography and UV detection

2016 ◽  
Vol 8 (27) ◽  
pp. 5441-5447 ◽  
Author(s):  
Débora R. S. Lima ◽  
Marcelo Cossenza ◽  
Carlos Gustavo Garcia ◽  
Camila C. Portugal ◽  
Flávia F. de C. Marques ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Embryo Development ◽  
Chicken Embryo ◽  
High Performance ◽  
Uv Detection

A HPLC-UV method has been developed and validated for the determination of ascorbic acid in chicken embryo retina.

Differential intestinal deconjugation of taurine and glycine bile acid N-acyl amidates in rats

1992 ◽  
Vol 262 (2) ◽  
pp. G351-G358
Author(s):  
R. Zhang ◽  
S. Barnes ◽  
R. B. Diasio
Keyword(s):  
High Performance Liquid Chromatography ◽  
Small Intestine ◽  
Liquid Chromatography ◽  
Bile Acid ◽  
Chenodeoxycholic Acid ◽  
High Performance ◽  
Biliary Fistula ◽  
The Difference ◽  
The Stability ◽  
Rat Bile

Mechanisms responsible for the difference in the relative amounts of taurine- and glycine-conjugated bile acid N-acyl amidates (Tau/Gly ratio) are not fully understood. In the present study, the stability of taurine- and glycine-conjugated bile acid N-acyl amidates during intestinal transit and absorption was examined to investigate the contribution of intestinal deconjugation to the Tau/Gly ratio in rat bile. Radiolabeled chenodeoxycholic acid (CDC) and its N-acyl amidates with glycine (CDC-Gly) or taurine (CDC-Tau) were introduced into the lumen of the upper small intestine in the biliary fistula rats, and radioactive metabolites in bile, blood, urine, and tissues were identified and quantitated by high-performance liquid chromatography. Results indicated that 1) extensive deconjugation of CDC-Gly occurs during intestinal absorption; 2) CDC-Tau is recovered in bile largely intact; and 3) newly synthesized CDC-Tau and CDC-Gly are formed in a ratio of less than 2:1 after administration of [14C]-CDC. In summary, the present study demonstrates that resistance of taurine-conjugated bile acid N-acyl amidates to hydrolysis in the intestine, rather than a difference in synthesis of taurine- and glycine-conjugated N-acyl amidates in liver, may account for the high Tau/Gly ratio in rat bile.

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