The investigation of chelate-enhanced fluorescence as an analytical tool for anion determination and the use of supercritical fluid extraction for metal speciation

This dissertation is divided into two different projects. Part A is the description of efforts at anion detection using chelation enhanced fluorescence coupled with flow injection analysis. Part B focuses on supercritical fluid extraction, and the use of this technique for the separation of metals by species, followed by detection with inductively coupled plasma atomic emission spectroscopy.; The first project discussed in this dissertation is an effort to develop a reagent for use in anion determination. This is an area in analytical chemistry that is lacking, while the area of cation determination has become well stocked with different reagents. The reason for this may be the ease of chelation with unoccupied d-orbitals of large cations, while anions usually must be chelated through electrostatic interaction coupled with size recognition. The ideal anion reagent is one that could be easily synthesized, and specific for an anion or class of anions. Another consideration would be the adaptability to different matrices. The use of chelation enhanced fluorescence (CHEF) combines a reagent that is easily adapted along with a detection technique that is selective and has low background levels. The anthrylmethylpolyamine was initially synthesized from Czamik's procedure. This reagent was then screened for chelating ability with different anions. The biggest effect was seen with adenosine triphosphate (ATP) with minimal interferences, a detection limit of 1{dollar}mu{dollar}M, a large linear range from 0.5 ppm to 100 ppm and an r squared value of 0.9997.; The second part of this dissertation focuses on the problem of metal speciation. In this dissertation speciation is defined as the separation and identification of different species of the same metal. The concern with determining different species of the same metal is due to the drastic difference in the toxicity levels of some of these species, as well as the tremendous difference in reactivity. The metals presented in this dissertation are chromium, mercury, and arsenic.; The separation of chromium (III) and chromium (VI) was performed at a high supercritical fluid density with methanol modifier and a fluorinated dithiocarbamate chelator. Chromium (VI) was extracted selectively at concentrations down to 100 ppb with 106% recovery, a standard deviation of 5.52%, and a relative standard deviation of 5.26% where n = 8. This separation is critical because Cr (VI) is toxic while Cr (III) is considered an essential micronutrient.; Speciation of mercury is important because the organic mercury compounds are more volatile, and more toxic than inorganic mercury compounds. In this work a method has been developed which uses SFE with ICP-AES analysis. The organomercury components are extracted selectively at low pressure with no additives, followed by extraction of inorganic mercury at high pressure with methanol modifier and fluorinated dithiocarbamate chelator. The two appendices contain the work on arsenic speciation which was not easily analyzed, and work an the low level determination of salicylic acid using flow injection analysis.