The aim of this study was to evaluate the performance of gas chromatography (GC)-triple quadrupole mass spectrometry (QqQ, MS/MS) as an alternative to the standard GC-high resolution mass spectrometry (GC-HR/MS) for soils contaminated with polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). GC-QqQ (MS/MS) using a dynamic multiple reaction monitoring (dMRM) mode was optimized for the quantitative analysis of 17 PCDD/Fs. A comparative study between GC-QqQ (MS/MS) and GC-HR/MS was carried out to validate the results of actual field soil samples. Although GC-HR/MS has excellent sensitivity and selectivity, the validation parameters obtained by GC-QqQ (MS/MS) also met the recommended criteria of the standard method. The results for total and I-TEQ (international toxic equivalent) value of the PCDD/F concentrations of over 86.0 pg/g and 4.3 pg I-TEQ/g, respectively, in actual field soil samples showed good agreement between the two methods, falling within ±25% relative difference. In consideration of the remediation goal (100 pg I-TEQ/g), GC-QqQ (MS/MS) can be an alternative cost-effective method for use in soil remediation research.
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Polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) are toxic chemicals that persist in the environment because of their lipophilicity and high chemical stability (Shin et al., 2017; Ayala-Cabrera et al., 2021; Zheng et al., 2008). PCDD/Fs gathered international attention because of the indiscriminate use of the herbicide Agent Orange, which contains large amounts of PCDD/Fs, by the United States Army during the Vietnam war from 1962 to 1971. This use led to severe environmental and health-related consequences such as high levels of contamination in the soil near to air bases used at the time and the incidence of congenital malformations and non-Hodgkin's lymphoma among the exposed population (de Lacerda, 2019). Seventeen toxic PCDD/PCDF congeners under environment regulation have been assessed with a total toxic equivalency (TEQ) value because of the toxicity risk associated with exposure to complex mixtures and because human exposure to PCDD/Fs is not to single compounds (Kutz et al., 1990; Bhavsar et al., 2008; Hens et al., 2016). The toxic potency of a mixture of PCDD/Fs is estimated by multiplying the concentrations of individual congeners by their respective toxic equivalent factor (TEF) and summing the products to yield a total TEQ (Hoogenboom et al., 2020). In accordance with the Vietnamese national technical regulation on authorized levels of PCDD/Fs in soils (Vietnam, 2012), the maximum PCDD/F content must not exceed 100 TEQ pg/g dw (Van den Berg et al., 2006; My et al., 2021). In Korea, a survey was conducted of the exposure level of PCDD/Fs in contaminated soil inside Camp Market, a US military base scheduled for return to civilian use in the Bupyeong district of Incheon. The investigation detected PCDD/Fs at all 33 survey sites. The highest concentration was 10,347 pg-TEQ/g, and seven of the 33 sites had values in excess of 1,000 pg-TEQ/g. For remediating contaminated soil, a variety of treatment methods have been applied in numerous countries (Weber et al., 2008; Jonsson et al., 2010; Tran et al., 2022). A number of instrumental and biological methods have been used for screening PCDD/Fs such as electron capture detection (ECD), bioassays, and immunoassays (EPA, 2002; EPA, 2014a,b; Draper et al., 1991; Harrison and Carlson, 1997; Klasmeier and McLachlan, 1998). Although these methods have been used successfully, there are limitations in terms of accurate identification and quantification of individual PCDD/F congeners. Traditionally, gas chromatography (GC) coupled with high-resolution mass spectrometry (GC-HR/MS) has been used as the authorized method. However, the method is not easily accessible in general laboratories because of the high cost of capital investment and maintenance (Focant et al., 2005; García-Bermejo et al., 2015; Franchina et al., 2019). Furthermore, GC-HR/MS has the disadvantage that the instrument is easily contaminated after high-concentration analysis and extreme care is required (Reiner, 2010). Unfortunately, the quantitative remediation goal for soil is relatively high, unlike that for food and other samples (Grant et al., 2015). A barrier in the case of remediation technologies for cleaning up contaminated sites is the high cost of the inspection fee for sample testing (thousands of samples per year) using GC-HR/MS. The cost per one sample is similar to the thermal remediation cost for 1 m3 of PCDD/F contaminated soil. Recently, GC-triple quadrupole mass spectrometry (QqQ, MS/MS) has been attempted with environmental samples as an alternative to GC-HR/MS (Palmiotto et al., 2013; Hashimoto et al., 2021). For operation costs, GC-HR/MS requires 1.3–3 times more for capital investment, and 1.5 times more for maintenance compared with GC-QqQ (MS/MS) (Reiner, 2010). Moreover, the analytical service charge is about 10 times higher per one sample when using GC-HR/MS than using GC-QqQ (MS/MS).This work was supported by a KBSI research grant (C230420) and by the Korea Ministry of Environment (MOE) as the “Subsurface Environment Management (SEM)” Program [project No. 2021002470001].
This work was supported by a KBSI research grant ( C230420 ) and by the Korea Ministry of Environment (MOE) as the “ Subsurface Environment Management (SEM) ” Program [project No. 2021002470001 ].
© 2022 The Authors
- Cost effective
- Gas chromatography
- High-resolution mass spectrometry
- Polychlorinated dibenzo-p-dioxins and dibenzofurans
- Triple quadrupole mass spectrometry