Abstract

A pump-probe thermal lens instrument was constructed, evaluated, and applied to the determination of metals after extraction with dithizone in carbon tetrachloride. An argon-ion laser operated at 514.5 nm, with a power of just 22 mW at the cuvette position and chopped at 2 Hz, and a He-Ne laser were used as a pump and probe, respectively. The thermal lens effect was measured by a pinhole-photodiode and a lock-in amplifier. Evaluation of the setup with an iodine solution in carbon tetrachloride gave a minimum detectable absorbance of 5 × 10<sup>−6</sup>(S/N = 3), the upper limit of the dynamic range being 5.7 × 10<sup>−3</sup>. Relative standard deviation was about 3%. Calibration curves and limits of detection for several metal dithizonates were obtained. From extractions of cadmium dithizonate at concentrations lower than 2 ng mL<sup>−1</sup>, a LOD of 8 pg mL<sup>−1</sup>, corresponding to an absolute LOD of 4 fg of cadmium in the probe volume, was achieved.

PDF Article

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription