Abstract
The occurrence and removal efficiency for naproxen, ibuprofen and diclofenac in two of eThekwini Municipality’s wastewater treatment plants (WWTPs), Kingsburgh and Umbilo, were investigated. This paper describes a simple method that can be used routinely for the simultaneous determination of such compounds in the influent and effluent of the WWTPs. Target compounds were extracted from wastewater and pre-concentrated using the optimized Oasis MAX solid-phase extraction (SPE) method. During SPE, the pH of wastewater samples was adjusted to 2.5; then 100 mL of each sample was loaded onto a pre-conditioned cartridge. The SPE cartridge was rinsed with methanol:water (10:90%, v:v) prior to sequential elution of retained analytes with 2 mL methanol, followed by 2 mL methanol and acetic acid (90:10, v:v) and 2 mL of 2% (v:v) formic acid diluted using a mixture of methanol and acetic acid (40:60, v:v). The eluted analytes from the SPE cartridge were quantified using high performance liquid chromatography (HPLC) equipped with photo diode array detection. The analytical method was validated by spiking deionized water with 5 and 50 μg·L -1 of target compounds, for which the recovery range of 76 to 98% was achieved with good precision. The instrument quantification limits obtained were 0.1 μg·L -1 , for naproxen and 0.4 μg·L -1 for both ibuprofen and diclofenac. The detected concentrations for naproxen, ibuprofen and diclofenac in the influent of both WWTPs were in the ranges of 15–20 μg·L -1 , 55–69 μg·L -1 and 6.4–16 μg·L -1 , respectively. In effluent, the detected concentrations for naproxen, ibuprofen and diclofenac were in the ranges of 0.6–1.1, 2.1–4.2 and 1.4–2.0 μg·L -1 , respectively. Overall, the employed SPE-HPLC method led to rapid pre-concentration of target compounds prior to their trace quantification in wastewater samples. Keywords: solid-phase extraction, wastewater treatment plants, ibuprofen, naproxen, diclofenac
Highlights
The presence of pharmaceutical compounds in the environment is a growing concern to analytical chemists and the general public. Pharmaceutical compounds such as naproxen, ibuprofen and diclofenac are useful compounds that belong to the group of non-steroidal anti-inflammatory drugs (NSAIDs)
When a water sample is acidified to a pH that is less than the pKa value of target compounds given in Table 1, the acids are non-ionized which leads to their adsorption through the reversed-phase interactions (Lee et al, 2005)
The application of advanced high performance liquid chromatography (HPLC) equipped with photo diode array detector for environmental analyses has allowed for the separation and quantification of ibuprofen, naproxen and diclofenac in wastewater
Summary
The presence of pharmaceutical compounds in the environment is a growing concern to analytical chemists and the general public. Pharmaceutical compounds such as naproxen, ibuprofen and diclofenac are useful compounds that belong to the group of non-steroidal anti-inflammatory drugs (NSAIDs). These organic compounds are polar and acidic. NSAIDs are widely used by humans for the treatment of rheumatoid arthritis (Mahkam and Poorgholy, 2011). Once consumed, they are subjected to human metabolism, followed by excretion in urine and faeces as metabolites and as unaltered parent compounds, which can be subjected to further transformations in wastewater treatment plants (WWTPs) (Parrilla Vazquez et al, 2013)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
