||This thesis describes: (i) A literature review concerning the historic development of hydride generation atomic spectrometric determinations. Inter-element interferences are identified in the literature. However, literature techniques for dealing with these interferences were either incomplete, inadequate, inappropriate or were not applied to a wide range of samples. (ii) The determination of arsenic and selenium in difficult sample matrices. Instrumental methods, preliminary studies and final digestion procedures were developed. (iii) The inter-element interferences found during the determination of hydride forming elements utilizing Atomic Absorption and Inductively Coupled Plasma Emission Spectrometry utilizing three commercially available hydride generation systems. Nineteen of fifty elements studied caused interferences. The selection of appropriate hydride generators and generating conditions aided in reducing these interferences. (iv) The effect of acid strength in reducing the interferences caused by those 19 elements. Nearly all interferences were reduced in high acid solutions; some interferences were eliminated. (v) The advantages of cation and anion exchange resins in reducing the interferent of analyte ratio. Chelex 100, widely used in the literature, was found to be inadequate for several of the sample types investigated. (vi) The effect of applying these techniques to a variety of environmental and agricultural sample matrices. Signal improvement was noted for Standard Reference Materials, Extraction Procedure Toxicity Leachates, Municipal Sludges and Coal Fly Ash which are representative of a broad range of environmental and agricultural samples.