TY - JOUR
T1 - Sequential injection determination of nitrate in vegetables by spectrophotometry with inline cadmium reduction
AU - Oliveira, Sara M.
AU - Lopes, Teresa I. M. S.
AU - Rangel, António O. S. S.
PY - 2007/2
Y1 - 2007/2
N2 - A sequential injection system for the determination of nitrate (NO 3-) in vegetables was developed to automate this determination, allowing for substantially reduced reagent consumption and generated waste using low-cost equipment. After extraction with water and filtration, the extracted nitrate is reduced inline to nitrite in a copperized cadmium (Cd) column and determined as nitrite. According to the Griess-Ilosvay reaction, nitrate is diazotized with sulfanilamide and coupled with N-(1-naphtyl)-ethylenediamine dihydrochloride to form a purple-red azo dye monitored at 538 nm. Nitrate can be determined within a range of 1.35-50.0 mg L-1 of NO3- (corresponding to 0.270-10.0 g of NO3- per kg of vegetable), with a conversion rate of nitrate to nitrite of 99.1 ± 0.8%. The results obtained for 15 vegetable extracts compare well with those provided by the classical procedure, with a sampling throughput of 24 determinations per hour and relative standard deviations better than 1.2%.
AB - A sequential injection system for the determination of nitrate (NO 3-) in vegetables was developed to automate this determination, allowing for substantially reduced reagent consumption and generated waste using low-cost equipment. After extraction with water and filtration, the extracted nitrate is reduced inline to nitrite in a copperized cadmium (Cd) column and determined as nitrite. According to the Griess-Ilosvay reaction, nitrate is diazotized with sulfanilamide and coupled with N-(1-naphtyl)-ethylenediamine dihydrochloride to form a purple-red azo dye monitored at 538 nm. Nitrate can be determined within a range of 1.35-50.0 mg L-1 of NO3- (corresponding to 0.270-10.0 g of NO3- per kg of vegetable), with a conversion rate of nitrate to nitrite of 99.1 ± 0.8%. The results obtained for 15 vegetable extracts compare well with those provided by the classical procedure, with a sampling throughput of 24 determinations per hour and relative standard deviations better than 1.2%.
KW - Copperized cadmium column
KW - Nitrate
KW - Sequential injection analysis
KW - Spectrophotometry
KW - Vegetables
UR - http://www.scopus.com/inward/record.url?scp=33847253534&partnerID=8YFLogxK
U2 - 10.1080/00103620601174635
DO - 10.1080/00103620601174635
M3 - Article
AN - SCOPUS:33847253534
SN - 0010-3624
VL - 38
SP - 533
EP - 544
JO - Communications in Soil Science and Plant Analysis
JF - Communications in Soil Science and Plant Analysis
IS - 3-4
ER -