Micro-sampling atomic absorption spectrometry using sample drops on a rotating polytetrafluoroethylene plate

Abstract

A micro-sampling method is proposed whereby drops of sample, pipetted on to a PTFE turntable, are sucked up by the negative pressure of the nebuliser and diluted in the carrier stream. Dilution is regulated by adjustment of the nebuliser. The presence of air in the tubing at the start of aspiration has a marked effect on absorption. The influences of sample flow-rate, sample volume and viscosity have been studied. The procedure described is very simple and requires only inexpensive additional equipment. The precision is about 1% RSD for 25-µl Cu^II samples. A throughput rate of 360 samples per hour is readily achieved.