Determination of phosphite (HPO3-2) by a new IC/MS/MS method using an 18O-labeled HPO3-2 internal standard

TALANTA

卷:230

Article

Sadeghi, Sepideh¹  Anderson, Todd A.²  Jackson, W. Andrew¹ 

[1] Texas Tech Univ, Dept Civil Environm & Construct Engn, Box 41023, Lubbock, TX 79409 USA

[2] Texas Tech Univ, Dept Environm Toxicol, Box 41163, Lubbock, TX 79409 USA

关键词: Phosphite;    IC/MS/MS;    Internal standard;   

DOI  :  10.1016/j.talanta.2021.122198

来源: Elsevier

【 摘 要 】

A new method has been developed to determine trace amounts of phosphite (HPO3-2) in environmental samples using ion chromatography with electrospray tandem mass spectrometry (IC-ESI/MS/MS). The method includes the production and use of an O-18-labeled HPO3-2 internal standard (IS). This isotopically labeled IS significantly improved sensitivity and could account for matrix suppression. The method detection limit (MDL) was determined as 0.017 and 0.034 mu g L-1 of HPO3-2 (6.5 and 13 ng P L-1) using a 500 and 25 mu L injection loop, respectively. Precision (1-10%) and accuracy (recoveries = 96-106%) were established for a range of environmental samples using known (spiked) addition. The impact of ionic interferences was investigated by evaluating the response of the internal standard in the presence of common anions with respect to distilled deionized water. The most significant interference was due to nitrate (100 mg-NO3 L-1) with a 99.99% reduction in IS intensity. The method was successfully applied to wastewater effluent, surface water, tap water, and soil samples. Relatively low concentrations <0.25 mu g HPO3-2 L-1 were measured in tap water, surface water and wastewater effluent, and similar to 1.6 mu g kg(-1) HPO3-2 in soil samples, using both injection loops. Limited suppression was observed for all matrices. The largest IS peak area suppression (similar to 98%) was observed in WW effluent with 500 mu L injection loop; however, this method was able to quantify HPO3-2 with good recoveries and precision despite the mentioned suppression, supporting the ability of the proposed method to quantify HPO3-2 in different environmental matrices.

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