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 mu g L-1 to 200 mu g 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.

Automated summary

The developed method combining ultrasonic assisted slurry sampling and in-situ DBD trap-OES technology is capable of fast determination of arsenic in soil. With simple pretreatment procedures, low detection limit, and good accuracy, it is suitable for soil analysis.