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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.


Effect of time on reaction rate of 1.0 ml of 10−3 M ABTS mixed with 3.0 ml of 0.1 M HCl and 1 ml of 5.0 ppm nitrite solution. The mixture was made to 10.0 ml by deionized water in volumetric flask. The absorption spectra were scanned at 2 minutes time intervals.
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f5-aci-1-2011-037: Effect of time on reaction rate of 1.0 ml of 10−3 M ABTS mixed with 3.0 ml of 0.1 M HCl and 1 ml of 5.0 ppm nitrite solution. The mixture was made to 10.0 ml by deionized water in volumetric flask. The absorption spectra were scanned at 2 minutes time intervals.

Mentions: Figure 5 shows the effect of time on the reaction rate of 1.0 ml of 10−3 M ABTS mixed with 3.0 ml of 0.1 M HCl and 1.0 ml of 5.0 ppm nitrite. A slow reaction that needs long time to be terminated was observed. Calibration curves at different incubation time intervals were plotted and used for checking concentrations of standard nitrite samples. Two minutes incubation time gave the best linear regression and recoveries. The reason can be attributed to a change in the kinetic order of the reaction by time. Therefore, two minutes incubation time was used in our all subsequent measurements.


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)

Effect of time on reaction rate of 1.0 ml of 10−3 M ABTS mixed with 3.0 ml of 0.1 M HCl and 1 ml of 5.0 ppm nitrite solution. The mixture was made to 10.0 ml by deionized water in volumetric flask. The absorption spectra were scanned at 2 minutes time intervals.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5-aci-1-2011-037: Effect of time on reaction rate of 1.0 ml of 10−3 M ABTS mixed with 3.0 ml of 0.1 M HCl and 1 ml of 5.0 ppm nitrite solution. The mixture was made to 10.0 ml by deionized water in volumetric flask. The absorption spectra were scanned at 2 minutes time intervals.
Mentions: Figure 5 shows the effect of time on the reaction rate of 1.0 ml of 10−3 M ABTS mixed with 3.0 ml of 0.1 M HCl and 1.0 ml of 5.0 ppm nitrite. A slow reaction that needs long time to be terminated was observed. Calibration curves at different incubation time intervals were plotted and used for checking concentrations of standard nitrite samples. Two minutes incubation time gave the best linear regression and recoveries. The reason can be attributed to a change in the kinetic order of the reaction by time. Therefore, two minutes incubation time was used in our all subsequent measurements.

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.