Trace Selenium Measurement in Water Using Laser-Induced Fluorescence Assisted by Laser Ablation

Selenium detection and removal from industrial and mining effluents have gained attention recently due to the negative effects of this trace element on aquatic life. However, the current methods for the detection of selenium in effluents are off-line by nature. In order to fill this gap, we investigated the use of laser ablation-assisted laser-induced fluorescence (LA-LIF) to measure trace amount of selenium in aqueous solutions. LA-LIF measurements are real time, label-free, standoff, and require no consumables as well as no sample preparation. They can provide a field-amenable, versatile tool for the measurement of selenium in the whole water treatment chain. We describe the system utilized, the temporal and fluence optimization studies, and the resulting calibration curve, which is linear over a wide dynamic range from parts-per-billion to tens of parts-per-million concentration levels. We also show that the achieved limit of detection of selenium can reach 32 µg/L using LA-LIF, without any kind of preconcentration or matrix transfer.