Validation of bias in multianalyte determination methods. Application to RP-HPLC derivatizing methodologies

This paper reports a new approach for validating bias in analytical methods that provide simultaneous results on multiple analytes. The validation pro cess is based on a linear regression technique taking into account errors i n both axes. The validation approach is used to individually compare two di fferent chromatographic methods with a reference one. Each of the two metho ds to be tested is applied on a different set of data composed of two real data sets each. In addition, three different kinds of simulated data sets w ere used. All three methods are based on RP-high-performance liquid chromat ography (HPLC) and are used to quantify eight biogenic amines in wine. The two methods to be tested use different derivatizing procedures: precolumn 6 -aminoquinolyl-n-hydroxysuccinimidyl carbamate (AQC) and oncolumn o-phtalal dehyde (OPA), respectively. On the other hand, rite reference method uses d erivatization with OPA precolumn, Various analytes are determined in a set of samples using each of the methods to be tested and their results are reg ressed independently against the results of the reference method. Bias is d etected in the methods to be tested by applying the joint confidence interv al test to the slope and the intercept of the regression line which takes i nto account uncertainties in the two methods being compared, The conclusion s about the trueness of the two methods being tested varied according to wh ether the joint confidence interval test was applied to data obtained from various biogenic amines considered simultaneously or individually. (C) 2000 Elsevier Science B.V. All rights reserved.