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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.


Absorption spectra of 1.0 ml of the 10−3 M ABTS at different concentrations (0.1–0.6 ppm) of nitrite.
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f3-aci-1-2011-037: Absorption spectra of 1.0 ml of the 10−3 M ABTS at different concentrations (0.1–0.6 ppm) of nitrite.

Mentions: Figure 3 shows the UV-VIS absorption spectra of 1.0 ml of 10−3 M ABTS after successive additions of different volumes of standard nitrite solution to produce concentrations of 0.1–0.6 ppm. The broad intense band at 315 nm is attributed to the reduced form of ABTS. This band was not shown when ABTS totally existed in the reduced form. Upon conversion to the oxidized from (ABTS+), spectra showed broad intense bands at 415 nm. This strong band corresponds to the half oxidation of ABTS to ABTS•+ has been used for monitoring nitrite ions concentration in solution throughout our investigation. Figure 3 shows that by increasing nitrite concentration, the intensity of the 315 nm band decreased while that of 415 nm band increased. An isoesbertic point around 360 nm was obtained indicating a reversible redox reaction at equilibrium.


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)

Absorption spectra of 1.0 ml of the 10−3 M ABTS at different concentrations (0.1–0.6 ppm) of nitrite.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3-aci-1-2011-037: Absorption spectra of 1.0 ml of the 10−3 M ABTS at different concentrations (0.1–0.6 ppm) of nitrite.
Mentions: Figure 3 shows the UV-VIS absorption spectra of 1.0 ml of 10−3 M ABTS after successive additions of different volumes of standard nitrite solution to produce concentrations of 0.1–0.6 ppm. The broad intense band at 315 nm is attributed to the reduced form of ABTS. This band was not shown when ABTS totally existed in the reduced form. Upon conversion to the oxidized from (ABTS+), spectra showed broad intense bands at 415 nm. This strong band corresponds to the half oxidation of ABTS to ABTS•+ has been used for monitoring nitrite ions concentration in solution throughout our investigation. Figure 3 shows that by increasing nitrite concentration, the intensity of the 315 nm band decreased while that of 415 nm band increased. An isoesbertic point around 360 nm was obtained indicating a reversible redox reaction at equilibrium.

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.