Relative fluorescence quantum yields are determined using a computercontrolled luminescence spectrometer. The relative absorbances of the standards and unknowns are measured using the same instrument as for the fluorescence measurements. Relative quantum yields are presented for a wide range of compounds a t room temperature.

No abstract

An ultrasensitive method for determining total mercury concentrations in biological specimens is a prerequisite for monitoring exposure to chronic low-dose levels of Hg vapor such as those from dental silver amalgam fillings. The clinical consequences of such doses are currently in question. We describe an adaptation of a two-stage gold amalgamation preconcentration step combined with cold vapor atomic fluorescence spectrometric detection for Hg. At Hg concentrations of 40 and 350 nmol/L, the within-day assay CVs were 5% and 3%, respectively; between-day assay CVs were 8% and 5%, respectively. Accuracy, as demonstrated by analytical recovery, ranged from 98% to 105%. The detection limit for the assay is 50 pmol/L, which is suitable for measuring total Hg concentrations in specimens of human urine, blood, and breast milk, and in monkey kidney cortex and feces, obtained from subjects with and without amalgam fillings.

No abstract

A new conduction cooling device for low-temperature luminescence measurements is presented and its use evaluated in a pulsed source luminescence spectrometer, Fluorescence and phosphoresence quantum yields are reported for some polyaromatic hydrocarbons a t 77 K.