**7. Results and suggestions**

pharmaceuticals by humans with antipyretic activities in some countries such as South Africa [64]. The emerging environmental pollutants such as antiretroviral drugs (ARVs) are imprinted [63, 65], however, there is still limited/no information on their environmental extraction using MISPE. Most MISPE applications for ARVs are based on their extraction from biological samples [66, 67]. The application of MISPE allows for pre-concentration of various analytes from environmental samples which in turn lead to very low detection limits in μg.L−1 to ng.L−1 levels (**Table 4**). Based on higher extraction efficiency or percent recoveries for pharmaceuticals, MIPs show strong ability to extract such drugs from complex sample matrices such as wastewater. As can be seen in **Table 4**, various amounts of MIPs are used in SPE. Small quantities as demonstrated by Zunngu

One of the most important applications of MIPs is their usage as the chromatographic stationary phases. This is done by slurry packing the prepared MIP into the stainless still chromatographic column. During the application, the imprinted molecule binds strongly to the packing material, which results in its strong retention and longer retention time [56]. This application was demonstrated in literature where a chiral stationary phase for the enantioselective separation of naproxen was reported [56]. In their work [56], a MIP was synthesized using (*S*)-naproxen as the template and evaluated for chromatographic separation. Racemic naproxen was efficiently resolved on the MIP with (*S*)-naproxen eluted last. Similarly, Haginaka and Sanbe, [70], synthesized a uniformly sized MIP for (*S*)-naproxen that gave good enantioselectivity and resolution for naproxen. In addition, uniform-sized MIP material for (*S*)-propranolol when applied as chromatographic stationary phase has shown the ability to separate (*S*)-propranolol from a mixture that contains some structurally related β-adrenergic antagonists [71]. Due to the strong binding of target compound onto MIP, peak tailing on the chromatogram is usually evident. Therefore, there are opportunities relating to the improve-

**Elution Analytical method** 

2 mL of methanol/ acetic acid (9:1, v:v)

1 mL of acetic acid and methanol (1:9)

5 mL of methanol LC-UV

**and detection limit**

LC–MS/MS LOD – Not reported

LOD – 25 μg.L−1

LC-DAD-ESI/MS LOD – 1.5–3.4 ng.L−1

LOD – 0.23 μg.L−1

LOD – 0.03 μg.mL−1

**Reference**

[36]

[68]

[69]

[3]

[25]

et al. [3] are the significant of potential application in miniaturization techniques.

**6.2. Chromatographic analysis**

60 Recent Research in Polymerization

**Analyte Sorbent** 

**amount (mg)**

Diclofenac 35 1000 mL wastewater and

Carbamazepine 200 100 mL wastewater effluent

Metformin 50 50 mL aqueous samples

ment of the quality of the resulting chromatograms.

**loading**

river water

at pH 11

pH 10

**Table 4.** MISPE of pharmaceuticals from environmental waters.

**Environmental sample** 

including wastewater,

Ketoprofen 14 50 mL wastewater at pH 5 1 mL of methanol LC-UV

Indomethacin 200 100 mL river water at pH 5 2 mL methanol LC-UV

In the earlier sections of this chapter, the evidence of the improved selectivity due to the application of MIPs in analytical methods has been demonstrated (**Figure 1**). In numerous occasions, the quantification of some pharmaceutical drugs in the environment has been performed after sample clean-up and analyte(s) pre-concentration using MISPE. After preconcentrated with MISPE, pharmaceutical compounds have been detected at concentration levels that range from low ng.L−1 to μg.L−1 [3, 26, 37, 44, 61]. In this chapter, it was further elaborated that there are MIP sorbents that are available commercially, and therefore, it is suggested that more sorbents should be available in the near future as more pharmaceuticals are being detected in the environment. Moreover, there are no reports in literature for MIPs synthesized for a number of pharmaceutical compounds more especially those that are new in the market. For example, in their recent review paper, Madikizela et al. [29] observed that the MIP for fenoprofen is yet to be developed. In different perspective, the potential for MIPs to be applied as chromatographic stationary phases for separation of complex mixtures such as enantiomers have been investigated extensively in the early 2000 [56, 70, 71]. Due to the promising results reported in previous years, it is suggested that this area should be exploited more carefully in order to improve the quality of chromatographic peaks, that could lead to better quality of analysis and results that are more reliable can be achieved. This of cause could lead to the introduction of new stationary phases by the manufacturers of chromatographic equipment and consumables.
