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Method using gas chromatography mass spectrometry (GC-MS) for analysis of nitrate and nitrite in vegetables

Lookup NU author(s): Othman Qadir, Jean Teh

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Abstract

Accurate analytical methods are very important to detect the contents of chemical substances in vegetables and fruit. There is particular interest in nitrate and nitrite, due to their possible benefits and harm on human health. The aim of this research is to modify the method of measurement of nitrate and nitrite by GC-MS for use in vegetables. Many procedures are available to measure nitrate (NO3) and nitrite (NO2). Some examples are: capillary electrophoresis, spectrophotometry using the Griess reaction, various HPLC methods and different types of isotope dilution GC-MS: with electron ionisation by nitration of mesitylene, and with chemical ionisation by derivatisation with pentafluorobenzyl bromide. However, some of these methods are mostly used in research on human health, to measure nitrate and nitrite in human biological fluids such as plasma or urine. Methods developed for analysis of vegetable samples often give variable results, for example due to interference from coloured compounds in the plant material. Therefore, we tried to modify the GC-MS method using pentafluorobenzyl bromide and chemical ionisation to optimise it for analysis of nitrate and nitrite in vegetable samples. Experiments were carried out to maximise peak area, in particular for nitrate. Factors that were tested were gas pressure, derivatisation reaction time and temperature, duration of nitrogen flushing, time of vortex after adding toluene during sample preparation, and amount of water added to separate the phases. The modified method was used to analyse contents of nitrate and nitrite in samples from a range of different vegetables


Publication metadata

Author(s): Qadir O, Teh J, Siervo M, Seal C, Brandt K

Editor(s): D’Haene K; Vandecasteele B; De Vis R; Crappé S; Callens D; Mechant E; Hofman G; De Neve S

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: NUTRIHORT : Nutrient management, innovative techniques and nutrient legislation in intensive horticulture for an improved water quality

Year of Conference: 2013

Pages: 258-264

Print publication date: 16/09/2013

Online publication date: 14/09/2013

Date deposited: 04/08/2017

URL: http://www.ilvo.vlaanderen.be/nutrihort

DOI: 10.13140/2.1.1891.8082

Library holdings: Search Newcastle University Library for this item

ISBN: 9789040303463


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