Variance study of burette aliquot volumes

Abstract

An experimental study using gravimetry was carried out in order to measure the variances observed in aliquot volumes delivered by graduated burettes operating with various flow-rates and surface tensions and with the burette tip immersed and not immersed in the receiving liquid. Aliquot mass versus meniscus level data were analysed for the aliquot volume variance by a maximum likelihood calculation that corrected for random and systematic mass errors including liquid evaporation. The observed variances provide estimates of titrant volume standard deviations for analytical chemists using non-linear regression analysis to extract parameter values and standard errors from potentiometric titration data.