A simple and accurate method to determine nitrite and nitrate in serum based on high‐performance liquid chromatography with fluorescence detection

Abstract

A simple method for accurate determination of nitrite and nitrate in serum was proposed to avoid the variation of nitrate reduction. For nitrite determination, serum samples were directly precipitated with methanol pre-nitrate conversion, and then the supernatant reacted with 2,3-diaminonaphthalene (DAN) to form 2,3-naphthotriazole (NAT), which was quantitatively analyzed by high-performance liquid chromatography coupled with fluorescence detection (HPLC-FL). For nitrate determination, samples were firstly heated at 70°C for 10 min to inactivate endogenous reductase-inhibiting proteins, then nitrate in the samples was quantitatively reduced to nitrite by reductase added experimentally. The difference in total nitrite concentrations between pre- and post-nitrate conversion was used to calculate the amount of nitrate in the samples. In addition to good specificity, high sensitivity, satisfactory accuracy and reproducibility, our method is simple and suitable for the quantitative determination of nanomolar level of nitrite and nitrate in a large number of serum samples.

Selective nitrate detection by an enzymatic sensor based on an extended-gate type organic field-effect transistor

“…fluorometric (Biswas et al, 2004) methods, while that of high-performance liquid chromatography (5 ppb, Shu-yu et al, 2013) is further lower than our OFET-based sensing system. However, the further improvement of sensitivity could be achieved by OFET-based amplifiers (Fukuda et al, 2015), which is thus in progress in our laboratory.…”

Portable device for the detection of colorimetric assays

“… method linear detection range (mg l −1 ) limit of detection (mg l −1 ) portability ref. UV–vis 0.1–1.6 0.1 no this work HPLC–UV 0.1–100.0 0.05 no [ 52 ] Spectrofluorometric 0.005–0.500 2.5 × 10 −3 no [ 53 ] Spectrophotometric ion-pair HPLC 0.01–0.1 0.1 no [ 54 ] our device 0.4–1.6 0.2 yes this work …”

Quantitative Analysis of Drugs in Biological Matrices by HPLC Hyphenated to Fluorescence Detection

“…The LOQ of histamine was 0.145 ng/ml in psoriatic plaques and 0.015 ng/ml in urine, respectively. Shu-yu et al [67] proposed an approach to quantify nitrite and nitrate (reduced to nitrite) in rat serum. Nitric oxide (NO) is a messenger molecule that possesses a wide variety of physiological activity.…”