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Alternative Validation of a LC‐MS/MS‐Multi‐Method for Pesticides in Drinking Water
Author(s) -
Müller Alexander,
Flottmann Dirk,
Schulz Wolfgang,
Seitz Wolfram,
Weber Walter H.
Publication year - 2007
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.200700014
Subject(s) - central composite design , chromatography , analyte , robustness (evolution) , dwell time , design of experiments , response surface methodology , chemistry , analytical chemistry (journal) , mathematics , statistics , medicine , clinical psychology , biochemistry , gene
Abstract The development of instrumental analytics such as the LC‐MS/MS has made it possible to quickly determine many component concentrations in a single chromatogram. However, the validation of such multi‐methods needs new strategies for robustness and optimization. Statistical execution of analytical tests is one tool that can be utilized to meet this requirement. A Central Composite Design (CCD) was utilized for the validation of an LC‐MS/MS multi‐method for 84 analytes. The experimental design includes six design variables and two non‐design variables (response variables). Concentration, ionization temperature, dwell time, gradient, flow (of eluent), and spraying/curtain gas (continuous design variables) were varied on five different levels; the whole design encompassed 91 runs. To investigate the robustness of a LC‐MS/MS method both peak sensitivity and chromatographic separation had to be verified. Therefore, two non‐design variables were necessary. The distribution of the peaks over analysis time was applied to describe the quality of the chromatographic separation. The sensitivity was described with the signal to noise ratio (S/N). The evaluation of the measured data was accomplished with the Analysis of Variance (ANOVA) and the Response Surface Methodology (RSM). Three main effects (concentration, ionization temperature, dwell time) and no significant interaction effect were found for the response variable “S/N”. The variables of concentration, ionization temperature, and dwell time had no significant effects for the response variable “S/N”. The ANOVA of the response variable chromatographic separation abandoned no significant effects as well. Therefore, robustness of the method can be guaranteed for all non significant design variables.