Characterization of a Tunable Optical Parametric Oscillator Laser System for Multielement Flame Laser Excited Atomic Fluorescence Spectrometry of Cobalt, Copper, Lead, Manganese, and Thallium in Buffalo River Sediment

Abstract

A pulsed (10 Hz) optical parametric oscillator (OPO) laser system based on β-barium borate (BBO) crystals and equipped with a frequency-doubling option (FDO) was characterized for use in laser excited atomic fluorescence spectrometry (LEAFS). This all-solid-state laser has a narrow spectral line width, a wide spectral tuning range (220−2200 nm), and a rapid, computer-controlled slew scan of wavelength (0.250 nm s^-1 in the visible and infrared, and 0.125 nm s^-1 in the ultraviolet). The output power characteristics (15−90 mJ/pulse in the visible, 1−40 mJ in the infrared, and 1−11 mJ in the ultraviolet), laser pulse-to-pulse variability (3−13% relative standard deviation, RSD, of the laser pulses), conversion efficiency of the FDO (2−17%), and spectral bandwidth in the visible spectrum (0.1−0.3 cm^-1) were measured. The laser was used as the excitation source for a flame LEAFS instrument for which rapid, sequential, multielement analysis was demonstrated by slew scan of the laser. The instrument allowed about 640 measurements to be made in about 6 h, with triplicate measurements of all solutions and aqueous calibration curves, which yielded accurate analyses of a river sediment (National Institute of Standards and Technology, Buffalo River Sediment, 2704) for five elements with precisions -¹), copper (2 ng mL^-1), lead (0.4 ng mL^-1), manganese (0.2 ng mL^-1), and thallium (0.9 ng mL^-1) by flame LEAFS.