Validation of Analytical Methods Used for Determination of Nitrate in Soil
Accred Qual Assur (2005) 10:172–176 DOI 10.1007/s00769-005-0914-6
PRACTITIONER’S REPORT
V. Kmecl J. SuÐin ˇˇ L. Zupancic-Kralj
Validation of analytical methods used for determination of nitrate in soil
Received: 7 April 2004 Accepted: 3 November 2004 Published online: 24 March 2005 Springer-Verlag 2005
V. Kmecl ()) · J. SuÐin Agricultural Institute of Slovenia, Hacquetova 17, 1000 Ljubljana, Slovenia e-mail: veronika.kmecl@kis.si Tel.: +386-1-2805164 Fax: +386-1-2805255 ˇˇ L. Zupancic-Kralj Faculty of Chemistry and Chemical Technology, University of Ljubljana, ˇ AÐkerceva 5, P.O. Box 537, 1000 Ljubljana, Slovenia
Abstract The standard method (ISO/ DIS 14255) and the quick test were used for determination of nitrate in soil. We validated both methods using parameters such as accuracy, reproducibility within 1 day and between days, limit of detection and limit of quantification. The accuracy of the results was determined using the analysis of samples from the international interlaboratory scheme WEPAL. The accuracy of the standard method was good, while for the quick test the results were not accurate. The standard method showed a solid reproducibility of measurement results (in 1 day, relative standard deviation, RSD=0.2%; between days,
RSD=0.8%). The quick test gave poorer results (in 1 day, RSD=6%; between days, RSD=7%). We tried to established the compatibility of both methods on real soil samples and we were satisfied to obtain the correlation coefficient 0.98 using the regression straight line. The analyses with the quick field instrument are much simpler and cheaper than the standard laboratory analyses and can be used for advising on nitrogen fertilisation. Keywords Nitrogen · Validation · Segmented flow analyser · Quick field instrument
Introduction
Nitrate ions are the subject of numerous investigations today owing to their mobility and a relatively high content in soil. Unprofessional handling with nitrogen fertilisers often
PRACTITIONER’S REPORT
V. Kmecl J. SuÐin ˇˇ L. Zupancic-Kralj
Validation of analytical methods used for determination of nitrate in soil
Received: 7 April 2004 Accepted: 3 November 2004 Published online: 24 March 2005 Springer-Verlag 2005
V. Kmecl ()) · J. SuÐin Agricultural Institute of Slovenia, Hacquetova 17, 1000 Ljubljana, Slovenia e-mail: veronika.kmecl@kis.si Tel.: +386-1-2805164 Fax: +386-1-2805255 ˇˇ L. Zupancic-Kralj Faculty of Chemistry and Chemical Technology, University of Ljubljana, ˇ AÐkerceva 5, P.O. Box 537, 1000 Ljubljana, Slovenia
Abstract The standard method (ISO/ DIS 14255) and the quick test were used for determination of nitrate in soil. We validated both methods using parameters such as accuracy, reproducibility within 1 day and between days, limit of detection and limit of quantification. The accuracy of the results was determined using the analysis of samples from the international interlaboratory scheme WEPAL. The accuracy of the standard method was good, while for the quick test the results were not accurate. The standard method showed a solid reproducibility of measurement results (in 1 day, relative standard deviation, RSD=0.2%; between days,
RSD=0.8%). The quick test gave poorer results (in 1 day, RSD=6%; between days, RSD=7%). We tried to established the compatibility of both methods on real soil samples and we were satisfied to obtain the correlation coefficient 0.98 using the regression straight line. The analyses with the quick field instrument are much simpler and cheaper than the standard laboratory analyses and can be used for advising on nitrogen fertilisation. Keywords Nitrogen · Validation · Segmented flow analyser · Quick field instrument
Introduction
Nitrate ions are the subject of numerous investigations today owing to their mobility and a relatively high content in soil. Unprofessional handling with nitrogen fertilisers often
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