Antioxidant activity and total phenolic, organic acid and sugar content in commercial pomegranate juices

Methods for the detection and determination of nitrite and nitrate: A review.

Nitrate and nitrite quantification from cured meat and vegetables and their estimated dietary intake in Australians

Simultaneous determination of nitrite and nitrate in meat products and vegetables by capillary electrophoresis

This study reports the use of microfluidic paper-based analytical devices (μPADs) associated with colorimetric detection for the determination of nitrite in clinical, food and environmental samples. μPADs were fabricated by a simple and fast stamping process in a geometry containing eight circular detection zones and one central zone to sample inlet interconnected by microfluidic channels. The colorimetric determination of nitrite was performed through the modified Griess reaction. Detection zones were spotted with a 0.75 μL aliquot of a solution containing 50 mM sulfanilamide, 1.2 M hydrochloric acid and 4 mM N-(1-naphthyl)ethylenediamine. The monitoring of the background colorimetric response revealed good stability over 12 h for devices stored in the absence of light. After the addition of standard or real samples, the resulting images were captured with a scanner, converted to a color scale and analyzed in the magenta channel. The analytical sensitivity and the limit of detection achieved after a preconcentration stage were 0.56 (AU μM−1) and 5.6 μM, respectively. The preconcentration provided an enrichment factor of ca. 3.2 times. The concentration levels of nitrite were successfully determined in saliva, preservative water, ham, sausage and river water samples. The concentration levels attained for each sample using μPADs were compared to the values found by spectrophotometry and there was no significant difference from one another at a confidence level of 95%.

Colorimetric determination of nitrite in clinical, food and environmental samples using microfluidic devices stamped in paper platforms

The Use of Cationic Polymer for the Separation of Inorganic Anions by Capillary Electrophoresis

The determination of the organic acids, tartaric, malic, citric, lactic, succinic, and acetic, by capillary electrophoresis was investigated. The acids were separated on a polyethyleneimine (PEI)-coated capillary filled with 20 mM 6-aminohexanoic acid and 5 mM 2,4-dihydroxybenzoic acid and adjusted to pH 4.9. The anodic electroosmotic flow generated by the PEI coating favors the separation speed of organic acids. The method was applied to the determination of organic acids in white wine and fruit juices. ©1999 John Wiley & Sons, Inc. J Micro Sep 11: 541–543, 1999

M. Said Nutku

Papers

Simultaneous determination of nitrite and nitrate in meat products and vegetables by capillary electrophoresis

The Use of Cationic Polymer for the Separation of Inorganic Anions by Capillary Electrophoresis

Polyethyleneimine‐coated capillary electrophoresis capillaries for the analysis of organic acids with an application to beverages