Room Temperature Phosphorimetry as a New Spectrochemical Method of Analysis

Abstract

Luminescence spectroscopy has been extensively applied in the fields of clinical chemistry, biochemistry, and environmental chemistry. Proteins, nucleic acids, enzymes, drugs, and pollutants all show characteristic luminescence properties. The unexcelled sensitivity, selectivity, ease of sampling, and breadth of application of this method is of considerable interest to every analytical researcher and analyst. Whereas fluorimetry has become a well-established method for analysis [11, phosphorimetry has been used during the past decade only for a limited number of quantitative analyses, including the analysis of poly-nuclear aromatic compounds [2–41, coal tar fractions [5], air pollutants [6-8], impurities in petroleum fractions [9–111, detection of pesticides, and fungicides in foods [12–17], and the analysis of amino acids and pharmaceutical compounds in biological fluids [18–26]. Only recently has phosphorimetry been extensively developed into a practical qualitative and quantitative analytical method. Several papers have appeared in which the progress in instrumentation and methodology as well as the analytical uses of phosphorimetry were given [27–30]. In the 1960s the lack of use of phosphorimetry for quantitative analysis was primarily due to the great complexity and time needed to prepare and carry out an analysis at low temperature, and the poor precision and accuracy of measurements of snowed, opaque, or cracked inhomogeneous samples. In the early 1970s, improvements were achieved with techniques to enable the measurement of opaque matrices of organic solvents [31] and the development of time-resolved and phase-resolved phosphorimetry [32-361. However, in most phosphorimetric studies, the analysis still had to be performed using either low temperature rigid solvents of organic glasses, polymer matrices, or carefully degassed and purified solutions in order to minimize collisional triplet quenching. These requirements still are the main disadvantages which make this spectro-chemical method less-widely used than fluorimetry. Recently, the observed phenomenon of intense phosphorescence at room temperature (RTP) from ionic organic compounds adsorbed on a variety of supports, such as silica, alumina, paper, and asbestos [36, 37], has been proposed as a new analytical technique [38–42]. A large variety of ionic compounds of biological and clinical interest [38-40] has been investigated by this new method. The use of external heavy atom perturbers has also been investigated for the determination of trace nonionic compounds, such as the polyaromatic hydrocarbons [41]. Significant progress has been achieved with the development of a simple device for automated RTP measurement [42].