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New spectrophotometric method for determining nitrogen dioxide in air using 2,2-azino-bis(3-ethyl benzothiazoline)-6-sulfonic acid-diammonium salt and passive sampling.

Salem AA, Soliman AA, El-Haty IA - Anal Chem Insights (2011)

Bottom Line: A new simple and highly sensitive spectrophotometric method for determining nitrogen dioxide in air was developed.Developed spectrophotometric method was shown to be one order of magnitude higher in sensitivity compared to the ion chromatographic method.These values indicated insignificant difference between the averages of the newly developed method and the values obtained by ion chromatography at 95% confidence level.Compared to continuous monitoring techniques, the newly developed method has shown simple, accurate, sensitive, inexpensive and reliable for long term monitoring of nitrogen dioxide in ambient air.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Faculty of Science, United Arab Emirates University, Al-Ain, United Arab Emirates.

ABSTRACT
A new simple and highly sensitive spectrophotometric method for determining nitrogen dioxide in air was developed. The method is based on converting atmospheric nitrogen dioxide to nitrite ions within the IVL passive samplers used for samples collection. Acidifying nitrite ions with concentrated HCl produced the peroxynitrous acid oxidizing agent which was measured using 2, 2-azino-bis(3-ethyl benzothiazoline)-6-sulfonic acid-diammonium salt (ABTS) as reducing coloring agent. A parallel series of collected samples were measured for its nitrite content using a validated ion chromatographic method.The results obtained using both methods were compared in terms of their sensitivity and accuracy. Developed spectrophotometric method was shown to be one order of magnitude higher in sensitivity compared to the ion chromatographic method. Quantitation limits of 0.05 ppm and 0.55 μg/m(3) were obtained for nitrite ion and nitrogen dioxid, respectively. Standard deviations in the ranges of 0.05-0.59 and 0.63-7.92 with averages of 0.27 and 3.11 were obtained for determining nitrite and nitrogen dioxide, respectively.Student-t test revealed t-values less than 6.93 and 4.40 for nitrite ions and nitrogen dioxide, respectively. These values indicated insignificant difference between the averages of the newly developed method and the values obtained by ion chromatography at 95% confidence level.Compared to continuous monitoring techniques, the newly developed method has shown simple, accurate, sensitive, inexpensive and reliable for long term monitoring of nitrogen dioxide in ambient air.

No MeSH data available.


Effects of HCl concentration on the reaction of 1.0 ml of 10−3 M ABTS mixed with 1.0 ml of 10 ppm nitrite solution into 10.0 ml volumetric flasks. 0.5–3 ml of 0.1 M standard HCl solution was added. The total volume was adjusted to 10.0 ml in each flask.
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f4-aci-1-2011-037: Effects of HCl concentration on the reaction of 1.0 ml of 10−3 M ABTS mixed with 1.0 ml of 10 ppm nitrite solution into 10.0 ml volumetric flasks. 0.5–3 ml of 0.1 M standard HCl solution was added. The total volume was adjusted to 10.0 ml in each flask.

Mentions: The effect of HCl concentration on the reaction rate was studied by adding 0.5–3 ml of 0.1 M standard HCl solution to 1.0 ml of 10−3 M ABTS mixed with 1.0 ml of 10 ppm nitrite solution and the total volume was made up to 10 ml by deionized water. Solutions were incubated for two minutes at room temperature and their UV-Vis spectra were scanned. The rate of reaction was found to increase with increasing HCl concentration as shown in Figure 4. After several experiments, 3.0 ml of 0.1 M. HCl showed nearly the complete conversion of 1.0 ml of 10−3 M ABTS to ABTS+. Therefore all subsequent measurements were made using 3 ml of 0.1 M HCl.


New spectrophotometric method for determining nitrogen dioxide in air using 2,2-azino-bis(3-ethyl benzothiazoline)-6-sulfonic acid-diammonium salt and passive sampling.

Salem AA, Soliman AA, El-Haty IA - Anal Chem Insights (2011)

Effects of HCl concentration on the reaction of 1.0 ml of 10−3 M ABTS mixed with 1.0 ml of 10 ppm nitrite solution into 10.0 ml volumetric flasks. 0.5–3 ml of 0.1 M standard HCl solution was added. The total volume was adjusted to 10.0 ml in each flask.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3117622&req=5

f4-aci-1-2011-037: Effects of HCl concentration on the reaction of 1.0 ml of 10−3 M ABTS mixed with 1.0 ml of 10 ppm nitrite solution into 10.0 ml volumetric flasks. 0.5–3 ml of 0.1 M standard HCl solution was added. The total volume was adjusted to 10.0 ml in each flask.
Mentions: The effect of HCl concentration on the reaction rate was studied by adding 0.5–3 ml of 0.1 M standard HCl solution to 1.0 ml of 10−3 M ABTS mixed with 1.0 ml of 10 ppm nitrite solution and the total volume was made up to 10 ml by deionized water. Solutions were incubated for two minutes at room temperature and their UV-Vis spectra were scanned. The rate of reaction was found to increase with increasing HCl concentration as shown in Figure 4. After several experiments, 3.0 ml of 0.1 M. HCl showed nearly the complete conversion of 1.0 ml of 10−3 M ABTS to ABTS+. Therefore all subsequent measurements were made using 3 ml of 0.1 M HCl.

Bottom Line: A new simple and highly sensitive spectrophotometric method for determining nitrogen dioxide in air was developed.Developed spectrophotometric method was shown to be one order of magnitude higher in sensitivity compared to the ion chromatographic method.These values indicated insignificant difference between the averages of the newly developed method and the values obtained by ion chromatography at 95% confidence level.Compared to continuous monitoring techniques, the newly developed method has shown simple, accurate, sensitive, inexpensive and reliable for long term monitoring of nitrogen dioxide in ambient air.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Faculty of Science, United Arab Emirates University, Al-Ain, United Arab Emirates.

ABSTRACT
A new simple and highly sensitive spectrophotometric method for determining nitrogen dioxide in air was developed. The method is based on converting atmospheric nitrogen dioxide to nitrite ions within the IVL passive samplers used for samples collection. Acidifying nitrite ions with concentrated HCl produced the peroxynitrous acid oxidizing agent which was measured using 2, 2-azino-bis(3-ethyl benzothiazoline)-6-sulfonic acid-diammonium salt (ABTS) as reducing coloring agent. A parallel series of collected samples were measured for its nitrite content using a validated ion chromatographic method.The results obtained using both methods were compared in terms of their sensitivity and accuracy. Developed spectrophotometric method was shown to be one order of magnitude higher in sensitivity compared to the ion chromatographic method. Quantitation limits of 0.05 ppm and 0.55 μg/m(3) were obtained for nitrite ion and nitrogen dioxid, respectively. Standard deviations in the ranges of 0.05-0.59 and 0.63-7.92 with averages of 0.27 and 3.11 were obtained for determining nitrite and nitrogen dioxide, respectively.Student-t test revealed t-values less than 6.93 and 4.40 for nitrite ions and nitrogen dioxide, respectively. These values indicated insignificant difference between the averages of the newly developed method and the values obtained by ion chromatography at 95% confidence level.Compared to continuous monitoring techniques, the newly developed method has shown simple, accurate, sensitive, inexpensive and reliable for long term monitoring of nitrogen dioxide in ambient air.

No MeSH data available.