Free Access
Volume 27, Number 2, March 1999
Capillary electrophoresis
Page(s) 181 - 185
Section Original articles
Analusis 27, 181-185 (1999)
DOI: 10.1051/analusis:1999164

Validation of the use of an automatic diluter in HPLC analyses by comparison with traditional methods

J. Vial1, A. Jardy1, P. Anger2 and G. Gorge2

1  Laboratoire "environnement et chimie analytique", associé au CNRS, École Supérieure de Physique et Chimie Industrielles de la Ville de Paris, 10 rue Vauquelin 75005 Paris, France
2  Centre de Recherche de Vitry Alfortville, Rhône-Poulenc Rorer, 13 Quai Jules Guesde, 94400 Vitry sur Seine, France

In an analysis protocol, dilution is nowadays the last step that is never (or seldom) fully automated. Yet special appliances called diluters are commercially available. In spite of the potential advantages in time and solvent saving, analysts are still reluctant to use these diluters, mainly because of the insufficient proof that they are able to give accurate and precise results. Validation by gravimetry did not represent an irrevocable argument since it could not account for memory effect. That is the reason why we chose to carry out our validation of the dilution step in HPLC analyses with an automatic diluter through a comparison with classical methods using flasks and pipettes or burettes. A parent solution made of concentrated Spiramycin was diluted by the various methods. The control analysis was operated using HPLC with UV detection. The experimental design involved two operators and results obtained were processed using statistical tools such as ANOVA and regression. Conclusions were that in any case the diluter was at least as effective as traditional methods. Observed variability introduced by dilution was 0.30% RSD with diluter, and 0.45% RSD with classical methods. In addition, as was shown by the results of the lack of fit test, diluter accuracy is quite compatible with linearity studies in HPLC. Consequently, it is possible and even advantageous to use a diluter instead of manual methods.

Key words: Dilution error / automatic diluter / validation / ANOVA / HPLC.

© EDP Sciences, Wiley-VCH 1999