HIGH-THROUGHPUT FAST-SCAN ANODIC-STRIPPING VOLTAMMETRY IN A MICROFLOWSYSTEM

A now-onto thin-layer electrochemical cell, incorporating Pt-based Hg microelectrodes, is used for fast scan anodic stripping voltammetry (F S-ASV) at microbore now rates, The slow now rates are uniformly altere d and controlled utilizing a gas displacement pump, Flow injection is carried out with a low-dead-volume six-port valve. In such a microflow system, the high precision that is observable in quiescent solutions is maintained, The detection limits (e.g., 0.17 nM for Cd2+ with a 2-m in preconcentration, or 0.19 pg of Cd2+ at 4.9 mu L/min) are remarkabl y lower than those previously reported in other now systems utilizing Hg microelectrodes, Compared to ASV in quiescent solutions and in othe r now systems, this setup has an excellent sample throughput and low s ample consumption, For example, at moderately fast scan rates (e.g., 1 5 V/s), one analysis of a sample containing Pb2+ or Cd2+ at submicromo lar levels takes about 10 s, with only 0.82 mu L of sample consumed, E xperimental conditions that govern the sensitivity, sample consumption , and throughput are discussed (i.e., scan rate, flow rate, Hg film th ickness, and preconcentration time), Finally, potential use of this de vice for automatic analyses is demonstrated.