Abstract
A twin six-port valve with two sample loops was installed between the autosampler and the nebuliser of a simultaneous inductively coupled plasma-atomic emission spectrometer. The valve was mounted close to the nebuliser inlet so that the time required for the sample to enter from the loop to the nebulizer was less than 0.5 s. The content of one loop was introduced to the nebulizer using a peristalic pump, whilst a second loop was filed with the next sample using a second peristaltic pump. The washout time was in this manner reduced by 20 s per analysis and the hourly sampling rate was increased from 90 to 180 in the measurements described.