A multi-channel dispenser-titrator-pH-stat

Abstract

A multi-channel dispenser-titrator-pH-stat with switch-selection of reagents and reagent volume control and with a directly digital read-out is described. A valve driven by a stepper motor is used to select reagents and as a coarse volume control. A drop generator dispensing-deflection mechanism is used as a fine volume control. The drop generator is also used to reject automatically to waste any reagent contaminated by previously dispensed reagent and, in the titration mode, to add various amounts of reagent to the reaction mixture. The instrument gives outstanding precision (relative standard deviation less than 0·2 per cent. over the range 0·5 to 7·0 ml) and linearity (correlation coefficient r= 0·999 over the ranges 0·01 to 1·0 and 0·25 to 7·0 ml).