کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5745721 | 1618780 | 2018 | 8 صفحه PDF | دانلود رایگان |
- Smartphone app-based monitoring tool for the detection of anionic surfactants including PFOA/PFOS.
- A standard deviation of <10% in 10-1000Â ppb range with a LOD of 10Â ppb, and possible lower LOD of 0.5Â ppb.
- Dual-LPE of â¼5Â min enabling on-site test by removing potential background interference.
- Validation by PFOA/PFOS spiked in tap water/groundwater at environmentally-relevant concentrations.
We developed a smartphone app-based monitoring tool for the detection of anionic surfactants (AS), including perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Akin to the methylene blue active substances (MBAS), liquid-phase extraction (LPE) is employed to extract the hydrophobic ion-pair of dye (ethyl violet)-AS to an organic phase (ethyl acetate). The colour (RGB) of the organic phase is read using a smartphone camera with the help of a reading kit. The value of RGB is carefully corrected and linked to the concentration of ASs with a standard deviation of <10% in the 10-1000Â ppb (part per billion) range. In order to avoid the interference arising from inorganic anions (such as those found in tap water and groundwater), the water sample is pre-treated either by solid-phase extraction (SPE), which takes â¼30Â min, or by dual liquid-phase extraction (dual-LPE, developed by us), which takes â¼5Â min. In the latter case, the organic phase of the first LPE (equilibrium with water sample) is transferred and subjected to a second LPE (equilibrium with Milli-Q water) to remove any potential background interference. In the meantime, SPE can also pre-concentrate ASs at 100-1000 times (in volume) to benefit the sensitivity. Consequently, our smartphone app can detect PFOA spiked in tap/groundwater with an LOD of 10Â ppb (â¼12Â nM, dual-LPE of â¼5Â min), or 0.5Â ppb (â¼1.2Â nM, SPE of â¼3Â h), suggesting that it has the potential to succeed as a pre-screening tool for on-site application and in common laboratory tests.
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Journal: Chemosphere - Volume 191, January 2018, Pages 381-388