Continuous Arsine Detection Using a Peltier-Effect Cryogenic Trap To Selectively Trap Methylated Arsines

Authors

Guoying Chen, USDA-ARSFollow
Bunhong Lai, USDA-ARS
Xuefei Mao, Chinese Academy of Agricultural Sciences
Tuanwei Chen, Fujian Agriculture and Forestry University
Miaomiao Chen, Jinan University

Document Type

Article

Date of this Version

2017

Citation

Anal. Chem. 2017, 89, pp. 8678−8682, DOI: 10.1021/acs.analchem.7b02635.

Comments

U.S. government work.

Abstract

Hydride generation (HG) is an effective technique that eliminates interfering matrix species and enables hydride separation. Arsenic speciation analysis can be fulfilled by cryogenic trapping (CT) based on boiling points of resulting arsines using liquid nitrogen (LN₂) as a coolant. In this work, LN₂ was replaced by the thermoelectric effect using a cryogenic trap that consisted of a polytetrafluoroethylene (PTFE) body sandwiched by two Peltier modules. After the trap was precooled, the arsines flew along a zigzag channel in the body and reached a sorbent bed of 0.2 g of 15% OV-3 on Chromosorb W-AW-DMCS imbedded near the exit of the trap. CH₃AsH₂ and (CH₃)₂AsH were trapped, while AsH₃, that passed the trap unaffected, was detected by atomic fluorescence spectrometry. Continuous operation led to enhanced throughput. For inorganic As, the limit of detection (LOD) was 1.1 ng/g and recovery was 101.0 ± 1.1%. Monomethylarsonic acid and dimethylarsinic acid did not interfere with 0.2 ± 1.2% and −0.3 ± 0.5% recoveries, respectively.