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unidentified PFAS precursors [130]. The TOF analysis is an indicator of the total fluorinated organic content 483

in a sample [131]. Electrochemical biosensors are an analytical device that detects the interaction between the 484

target analyte and antibodies, enzymes, DNA, cells, viruses, or microorganisms which are coupled to an 485

electrode for the detection of oxidation and reduction taking place [132]. Colorimetric sensing allows fast 486

analysis and low cost in assay-based detection of PFAS and the toxicities linked to it. PFA sensing is linked 487

by several mechanisms of chromophore generation. Colorimetric sensing involves the destabilization of gold 488

and silver nanoparticles, which leads to the generation of surface plasmons that can be optically monitored 489

and can be incorporated into paper-based assays [133]. Colorimetric assessment can also be done by the 490

complexation of PFA ions with cationic dyes. This creates hydrophobic phases that can be extracted to 491

compare with a standardized chart to determine substance concentration using an analysis similar to pH strips 492

[134]. Assays and kits that use colorimetric techniques can be used as a substitute to analytical detection 493

methods for their ease of use and convenience. Spectroscopic methods also have enough potential for the 494

sensitive detection of environmental contaminants and plastic nanoparticles [135]. The effects and risks of 495

PFAS can be addressed by linked biology–chemistry methods which first detect and then identify specific 496

chemicals. 497

5. Applications of PFAs 498

According to multiple expert studies conducted worldwide, per- and polyfluoroalkyl substances (PFAS) are a 499

growing source of concern [136, 137]. Due to their ubiquitous environmental prevalence, bio accumulative 500

characteristics, severe persistence, and evidence of negative health impacts, PFAs are a cause for concern 501
[138]. 502

PFAs are lipo- and hydrophobic persistent synthetic organo-fluorine chemicals that have a high degree of 503

stability. Due to their unusual hydrophobic and lipophobic properties and ability to withstand harsh 504

environmental conditions, a class of synthetic organo-fluorine chemicals known as "PFAS" has been used 505

since 1940 to refer to these chemicals. This class consists of about 5000 different substances and is used in a 506

variety of commercial applications [139, 140]. 507

The uses of PFAS are versatile and diverse. PFAS are commonly used to treat plastics and metals, as well as 508

in herbicides and fire extinguishing agents. They are chemically and thermally stable and repel dirt, grease, 509

and water. These PFAS substances are employed all over the world in products for the construction, 510