Unwanted loss of volatile organic compounds (VOCs) during in situ chemical oxidation sample preservation: Mechanisms and solutions

To assess the performance of hazardous waste sites remediation technologies like in situ chemical oxidation (ISCO) with persulfate (S2O82−) researchers must periodically measure concentrations of target contaminants. Due to the presence of relatively high concentrations of the residual oxidant expected in many samples, the standard analytical method requires the addition of a relatively high concentration of ascorbic acid to prevent the oxidation process from continuing after sample collection. We discovered that addition of ascorbic acid quencher results in a radical chain reaction that transforms two common halogenated solvents (i.e., tetrachloroethene and hexachloroethane). To avoid the artifact associated with the radical chain reaction, a small quantity of n-hexane can be added to aqueous samples to extract target compounds and protect them from the radical chain reaction initiated by addition of the quencher. We..., , # Unwanted loss of volatile organic compounds (VOCs) during in situ chemical oxidation sample preservation: Mechanisms and solutions

Dataset DOI: [10.5061/dryad.g1jwstr34](10.5061/dryad.g1jwstr34)

## Description of the data and file structure

This dataset contains raw and processed GC/MS data supporting Figures 1 and 2 in the associated manuscript, which examine unintended transformations of volatile organic compounds (VOCs) during sample preservation in in situ chemical oxidation (ISCO) experiments using persulfate and ascorbic acid. There are no blank cells in the data column. All values represent either detected signals.

### Files and variables

#### File: JHML\_Tae\_Scavenger\_Rawfile.xlsx

#### **Figure 1 data: Artifact Formation During Preservation with Ascorbic Acid**

The csv sheet titled **“Figure 1”** presents the experimental data demonstrating how the addition of ascorbic acid as a preservative in the presence of residual persulfate initiates a radical chain reaction tha...,