## 3 Pharmaceuticals Pollutants
### Detection, Sample Preparation and Analysis of NsaIDs and ARV Drugs  
There have been numerous analytical techniques developed for the simultaneous quantification and detection of pharmaceutical compounds [65]. Because of their diverse solubility, log Kow values, polarity, pKa values, physical-chemical properties, and low concentration in ecosystems, optimizing procedures for analyzing multidrug residues remains a global challenge [50]. Because matrices are complex and have low concentrations, extraction is required prior to sample analysis, pre-concentration, and sample clean-up [3]. Solid-phase extraction (SPE) is usually the method of choice for extraction and pre-concentration NSAIDs and ARV drugs from various environmental matrices [3]. The effectiveness of SPE is solely determined by the elution solvent and sorbent type [66]. Oasis HLB (lipophilic-hydrophilic balance), Oasis MAX (containing mixed mode and robust anion exchange groups), Strata-X (Phenomenex), Bond elute plexa, and molecular imprinted polymers (MIPs) are all commonly used sorbents in SPE. To retain polar and non-polar compounds, Oasis HLB contains divinylbenzene rings and N-vinyl-pyrrolidone groups [67]. Three or more cartridges are typically used to pre-concentrate the samples, and polar solvents (acetonitrile and methanol) are typically used for elution [68]. Purification and comprehensive extraction procedures, such as liquid chromatography-mass spectrometry (LC-MS), are required to study the fate of these pharmaceuticals and their occurrence in wastewater, rivers, and sewage sludge. After pre-treatment with SPE, samples are analyzed using various spectroscopic techniques such as liquid chromatography (LC) with fluorescence detection (FLD) and diode-array detection (DAD), high-performance liquid chromatography (HPLC), ultra-high-performance liquid chromatography (UHPLC), tandem MS using triple quadrupole or ion trap MS, and so on [69]. C8 and C18 columns with an elution mixture of acetonitrile/water or methanol/water are commonly used in HPLC to determine these pharmaceuticals [29]. Acetic and formic acid additions are also used to improve the mobile phase's efficiency in order to increase analyte sensitivity and ionization for mass detection [69]. Because of the high operating pressure, flow rate (mobile phase), reduced column length, and large particle surface area to achieve better resolution in a short separation time, LC-MS has several advantages over other techniques [70]. MS, coupled with LC, is one of the most effective methods for analyzing NSAIDs and ARV drugs and their residues, with a detection limit of ng L\({}^{-1}\). The majority of the techniques described focus on the parent compounds and rarely discuss their transformation products or residues. Hence, metabolites should be studied because they can be found in high concentrations with high toxicity, mobility, and persistence in the environment. So far, various approaches for detecting NSAIDs and ARV drugs in various environmental matrices have been proposed; they are broadly classified into polar and non-polar sorbents. in which solutes or removable species are transferred from a liquid phase to the surface of a solid phase [72]. Adsorbed substances are attached to the solid surface via physiochemical interactions. Adsorption has a removal effectiveness of up to 99.9%. The United States Environmental Protection Agency (USEPA) stated that the adsorption method, among others, is one of the most effective and finest wastewater treatment procedures [73]. Because of its simplicity and cost-effectiveness in comparison to other alternatives, adsorption is regarded as a well-developed technology for removing pharmaceuticals from wastewater. Adsorbate migration happens in three successive phases in this process: (i) migration of adsorbate to the adsorbent's border shell, (ii) intraparticle diffusion into pores, and (iii) adsorption and desorption of solute. The rate of all these processes is determined by the properties of the adsorbate, adsorbent, and matrix.