Corn leaf nitrate reductase - A nontoxic alternative to cadmium for photometric nitrate determinations in water samples by air-segmented continuous-flow analysis

Patton, C. J.; Fischer, A. E.; Campbell, W. H.; Campbell, E. R.

Abstract:

Development, characterization, and operational details of an enzymatic, air-segmented continuous-flow analytical method for colorimetric determination of nitrate + nitrite in natural-water samples is described. This method is similar to U.S. Environmental Protection Agency method 353.2 and U.S. Geological Survey method 1-2545-90 except that nitrate is reduced to nitrite by soluble nitrate reductase (NaR, EC 1.6.6.1) purified from corn leaves rather than a packed-bed cadmium reactor. A three-channel, air-segmented continuous-flow analyzer-configured for simultaneous determination of nitrite (0.020-1.000 mg-N/L) and nitrate + nitrite (0.05-5.00 mg-N/L) by the nitrate reductase and cadmium reduction methods-was used to characterize analytical performance of the enzymatic reduction method. At a sampling rate of 90 h-1, sample interaction was less than 1% for all three methods. Method detection limits were 0.001 mg of NO2- -N/L for nitrite, 0.003 mg of NO3-+ NO2- -N/L for nitrate + nitrite by the cadmium-reduction method, and 0.006 mg of NO3- + NO2- -N/L for nitrate + nitrite by the enzymatic-reduction method. Reduction of nitrate to nitrite by both methods was greater than 95% complete over the entire calibration range. The difference between the means of nitrate + nitrite concentrations in 124 natural-water samples determined simultaneously by the two methods was not significantly different from zero at the p = 0.05 level.

Genre:

Article

ProdID:

70025095

Citation Author:

Patton, C. J.; Fischer, A. E.; Campbell, W. H.; Campbell, E. R.

Citation Contributing Office:

Citation Datum:

Citation Day:

Citation Edition:

Citation Editor:

Citation End Page:

735

Citation Issue:

Citation Keywords:

Citation Language:

English

Citation Larger Work Title:

Environmental Science and Technology

Citation LatN:

Citation LatS:

Citation LonE:

Citation LonW:

Citation Month:

Citation No Pagination:

Citation Number Of Pages:

Citation Online Only Flag:

Citation Phsyical Description:

Citation Projection:

Citation Public Comments:

Citation Publisher:

Citation Series:

Citation Series Code:

Citation Series Number:

Citation Search Results Text:

Corn leaf nitrate reductase - A nontoxic alternative to cadmium for photometric nitrate determinations in water samples by air-segmented continuous-flow analysis; 2002; Article; Journal; Environmental Science and Technology; Patton, C. J.; Fischer, A. E.; Campbell, W. H.; Campbell, E. R.