Determination of Arsenic in Soil by Ultrasonic Assisted Slurry Sampling Hydride Generation (HG) in-Situ Dielectric Barrier Discharge Trap (DBD)-Optical Emission Spectrometry (OES)

An ultrasonic assisted slurry sampling procedure was coupled with hydride generation in-situ dielectric barrier discharge trap optical emission spectrometry (HG-in situ DBD trap-OES) to provide the simple and fast determination of arsenic in soil. The soil was treated HNO3 and HF in an ultrasonic bath for 25 min, subsequently diluted with 6% HCl (v/v) and 40 g L−1 thiourea, and placed into the ultrasonic bath again for 10 min to obtain a stable and homogeneous slurry that was introduced to HG-in-situ DBD trap-OES for As determination. Under the optimal conditions, the calibration coefficient exceeded 0.995 from 2 μg L−1 to 200 μg L−1. A method detection limit of 0.18 mg kg−1 was achieved for As in soil (250 times dilution) with a 3.4% relative standard deviation. The developed method was validated by the determination of As in three soil certified reference materials including GBW07430 (As, 18 ± 2 mg kg−1), GBW07447 (As, 10.7 ± 0.5 mg kg−1), and GBW07449 (As, 8.7 ± 0.6 mg kg−1), as well as two real soil samples. The results agreed well with the certified values and the measurements by inductively coupled plasma – mass spectrometry. With advantages of simple pretreatment procedures, small size/weight, low power consumption, and low manufacturing cost, the developed method has the potential to be widely applied in soil analysis.