Preparation of ion exchange films for solid-phase spectrophotometry and solid-phase fluorometry

Atomic spectroscopy has dominated the field of trace inorganic analysis bec ause of its high sensitivity and selectivity. The advantages gained by the atomic spectroscopies come with the disadvantage of expensive and often com plicated instrumentation. Solid-phase spectroscopy, in which the analyte is preconcentrated on a solid medium followed by conventional spectrophotomet ry or fluorometry, requires less expensive instrumentation and has consider able sensitivity and selectivity. The sensitivity gains come from preconcen tration and the use of chromophore (or fluorophore) developers and the sele ctivity is achieved by use of ion exchange conditions that favor the analyt e in combination with speciative chromophores. Little work has been done to optimize the ion exchange medium (IEM) associated with these techniques. I n this paper we present a method for making ion exchange polymer films whic h considerably simplify the solid-phase spectroscopic techniques. They are mechanically sturdy and optically transparent in the ultraviolet and visibl e portion of the spectrum, which makes them suitable for spectrophotometry and fluorometry.