Determination of asymmetric and symmetric dimethylarginines in human plasma by HPLC with electrochemical detection

Abstract

A new HPLC method was developed and validated for the determination of asymmetric and symmetric dimethylarginines and l-arginine in human plasma. After SPE and evaporation of the eluate, the samples were derivatised with an o-phthaldialdehyde reagent containing 3-mercaptopropionic acid. The derivatives formed were analysed by isocratic RP-HPLC with electrochemical detection at +320 mV. The mobile phase consisted of 50 mM phosphate buffer (pH 6.1) containing 10% v/v acetonitrile, the flow rate was 1 mL/min. The retention times of all compounds including monomethylarginine (internal standard) were <24 min. The LODs (S/N 3:1) were 0.012 μM for both dimethylarginines and 0.013 μM for L-arginine; the linearity of the method was from 0.1 to 20 μM for both dimethylarginines and from 1 to 200 μM for L-arginine. Absolute extraction recoveries measured for all analytes ranged from 85 to 88%.

Upregulated plasma and urinary levels of nucleosides as biological markers in the diagnosis of primary gallbladder cancer

“…To date, numerous methods have been utilized to purify nucleosides satisfactorily from a complex matrix of biological samples, such as urine, serum, blood, and even tissues [22,[24][25][26]. In our current study, we performed RP-HPLC analysis of ten different nucleosides in the urine, serum, blood, and even tissues and found that significantly increased levels of nucleosides were observed in the plasma and urine of gallbladder carcinoma patients.…”

“…Because there are no specific enzymatic systems to incorporate modified nucleosides into the macromolecular nucleic acid, these nucleosides once released cannot be reutilized, nor are they further degraded, but are excreted into the urine . Other studies also have demonstrated that urinary nucleoside excretion is little affected by the diet in humans, and when normalized to urinary creatinine levels, the daily excretion rate of urinary nucleosides is remarkably constant in healthy individuals . Thus, nucleoside detection could be useful in the assessment of human diseases, including cancer.…”

“…Thus, a large number of studies have emphasized that urinary nucleosides, especially modified ones, may be used as a diagnostic tool in human cancers, e.g. colorectal cancer [25,26], breast cancer [27][28][29], hepatocellular carcinoma [30,31], gastric cancer [32], and leukemia [33]. Therefore, in this study, we detected nucleoside levels in the urine, blood, and bile from patients with gallbladder carcinoma or gallstones and healthy controls to explore the usefulness of altered nucleoside levels as biomarkers in the early detection or prognosis of gallbladder carcinoma.…”

Highly selective capture of nucleosides with boronic acid functionalized polymer brushes prepared by atom transfer radical polymerization

“…Their concentration level in the biological fluids can reflect the situation of RNA degradation. Thus, they can be used as a diagnostic tool for human cancers and other degenerative diseases . It is therefore important to develop efficient and practical methods for nucleoside enrichment from complex biological samples.…”

Simultaneous determination ofNG-monomethyl-l-arginine,NG,NG-dimethyl-l-arginine,NG,NG′-dimethyl-l-arginine, andl-arginine using monolithic silica disk-packed spin columns and a monolithic silica column

“…Existing methods for the determination of methylated arginines include electrophoresis , ion‐exchange chromatography , monoclonal antibody assays , HPLC–UV , and HPLC with electrochemical detection . Several recently reported techniques have significantly higher sensitivity than earlier methods: LC–MS , MS/MS , CE–MS , CE–LIF , and UHPLC–MS .…”