Measurement uncertainty evaluation and in-house method validation of the herbicide iodosulfuron-methyl-sodium in water samples by using HPLC analysis
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A method for separation and quantitative determination of the iodosulfuron-methyl-sodium in water samples by high-performance liquid chromatography (HPLC) was developed and in-house validated in order to demonstrate its performance for monitoring of heterogeneous photocatalytic elimination of the herbicide iodosulfuron-methyl-sodium from water. Surface and ground water samples were used to demonstrate its selectivity, detection and quantification limits, linearity, trueness and precision. In addition, stability of iodosulfuron-methyl-sodium was studied in function of temperature and time. Method accuracy was quantified through measurement uncertainty estimate based on method validation data. The paper gives practical and easy to follow guidance on how uncertainty estimates can be obtained from method validation experiments. It shows that, if properly planned and executed, key precision and trueness studies undertaken for validation purposes can also provide much of the data needed to produce an estimate of measurement uncertainty. Our analytical protocol allowed us to quantify iodosulfuron-methyl-sodium in ground water and surface water in concentration level between 2.50–50.0 μmol L−1 with satisfactory recoveries (99–104%) and repeatability lower or equal than 0.3% for all the matrices. We also estimated within-laboratory reproducibility over 3-month period, which was 0.7%. We proved that the method was selective for determination of iodosulfuron-methyl-sodium in the relevant matrices. Measurement uncertainty of results was evaluated to be 4.0% with 95% confidence level. After validation and measurement uncertainty evaluation steps, results obtained showed that the method can be applied to efficiently monitor heterogenous photocatalytic degradation of the herbicide iodosulfuron-methyl-sodium.
KeywordsPhotocatalytic degradation HPLC Iodosulfuron-methyl-sodium Method validation Measurement uncertainty
The authors gratefully acknowledge financial support from the Ministry of Higher Education, Science and Technology of the Republic of Slovenia (Program P2-0150) and from the Metrological Institute of the Republic of Slovenia (MIRS).
- 5.BIPM, IEC, IFCC, ILAC, IUPAC, IUPAP, ISO, OIML (2008) The International Vocabulary of Metrology—basic and general concepts and associated terms (VIM), 3rd edn, JCGM 200Google Scholar
- 6.BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML (1995) Guide to the Expression of Uncertainty in Measurement, International Organization for Standardization, GenevaGoogle Scholar
- 7.Ellison SLR, Rosslein M, Williams A (eds) (2000) EURACHEM/CITAC, quantifying uncertainty in analytical measurement, 2nd edn. LGC, TeddingtonGoogle Scholar
- 8.Barwick VJ, Ellison SLR (1998) Protocol for uncertainty evaluation from validation data. VAM, TeddingtonGoogle Scholar
- 9.Magnusson B, Naykki T, Hovind H, Krysell M (2004) Handbook for calculation of measurement uncertainty in environmental laboratories (Nordtest Technical Report 537), 2nd edn. Nordtest, OslGoogle Scholar
- 10.ISO/IEC 17025 (2005) General requirements for the competence of testing and calibration laboratories, International Organization for Standardization, SwitzerlandGoogle Scholar
- 11.EURACHEM (1998) The fitness for purpose of analytical methods. Eurachem LGC, TeddingtonGoogle Scholar
- 17.Kruve A, Herodes K, Leito I (2010) J AOAC Intern 93:306–314Google Scholar
- 18.APHA-AWWA-WEF (2005) Standard methods for examination of water and waste water, WashingtonGoogle Scholar
- 19.Miller JN, Miller JC (2000) Statistics and chemometrics for analytical chemistry. Prentice Hall, LondonGoogle Scholar
- 20.ISO 8466-1 (1990) Water quality—Calibration and evaluation of analytical methods and estimation of performance characteristics—Part 1: Statistical evaluation of the linear calibration function, GenevaGoogle Scholar