GOLD ULTRAMICROELECTRODES FOR ON-SITE MONITORING OF TRACE LEAD

Gold and gold-coated cylinder microelectrodes are used as stripping-based microsensors for trace lead. These gold ultramicroelectrodes exhibit a favorable stripping performance, similar to that observed at common mercury ultramicroelectrodes. Such use of ''mercury-free'' electrodes greatly facilitates the development of disposable sensors for lead blood screening programs. Potentiometric stripping analysis at these gold ultramicroelectrodes yields reproducible results for parts per billion (mug/L) concentrations, of lead, following short preconcentration periods and using static, nondeaerated solutions. Numerous experimental variables have been characterized and optimized. Repetitive assays of 200-mul sample drops yield a relative standard deviation of 2.2% (n = 20). The application of the gold ultramicroelectrodes for assays of various real samples is demonstrated, and prospects for their use in decentralized testings are discussed.