A test of robustness in IIR-RP-HPLC separation of nine priority pollutant phenols

This study presents an example of method validation, applied to an IIR-RP-H PLC method, developed for the separation of nine PPPs (Priority Pollutant P henols). The parameters of both primary validation (accuracy, precision, re sponse linearity, detection. and quantitation limits,) and of secondary val idation (method ruggedness) are evaluated. The glossary used in literature for ruggedness and rabustness is discussed. The robustness test is carried out with respect to five chromatographic conditions, both depending on anal yst accuracy (concentration of the ion-interaction reagent, concentration o f the organic modifier, and pH of the mobile phase) and on instrumentation (column temperature and few-rate). The effect of the experimental factors is studied by a fractional factorial design and mathematical models are built, that correlate the chromatograph ic retention to the experimental factors and to their interactions. The cro ss-validated models can usefully be employed to evaluate for each studied v ariable the region of acceptable ruggedness for any given confidence level.