[en] Contamination of low molecular weights polycyclic aromatic hydrocarbons (PAHs) is common in beverage and water. This could pose a health risk to those beverage lovers when they consume the products. Phenanthrene (PHE) is one of the low molecular weights PAHs that consists of three benzene rings in the molecular structure. In this study, PHE was chosen as the model analyte due to its mid-volatility behavior. A headspace membrane-protected liquid phase microextraction (HS-MP-LPME) combined with high performance liquid chromatography-fluorescence detection (HPLC-FD) has been developed for the analysis of PHE in beverage and water samples. The nylon membrane containing 1-octanol as the extractant was exposed to the headspace of the sample vial containing 25 mL of sample solution. The extraction was performed at its optimal conditions with sample temperature fixed at 60 degree Celsius, agitation set at 700 rpm and extraction conducted for 30 minutes. Under these optimal extraction conditions, the HS-MP-LPME-HPLC-FD offered ultra-trace detection of PHE and insignificant matrix effects in beverages (green tea and coffee) and water (river, sea and tap) samples with average of relative recovery in the range of 83.7 to 116.1 %. The HS-MP-LPME simplifies the routine analysis and resolves the extractant dissolution problem that commonly occurs in hollow fiber-protected LPME. The proposed technique consumes only minimal amounts of organic solvent (200 μL) and this indirectly supports our National Green Technology Policy: together we create a better tomorrow. (author)

[en] Sample preparation is important to produce a clean extract to enhance detection sensitivity and minimize instrument maintenance. A micro-solid phase extraction (µ-SPE) technique using magnetic molecularly imprinted polymers (magnetic-MIPs) as the adsorbents combined with micro-high performance liquid chromatography and ultraviolet detection (µ-HPLC-UV) has been developed for the determination of selected polycyclic aromatic hydrocarbons (PAHs), namely benzo[a]pyrene, phenanthrene, fluoranthene and pyrene in environmental water samples. The magnetic-MIPs were characterized using scanning electron microscopy, Brunauer–Emmett–Teller, thermogravimetric analysis and vibrating sample magnetometer to finalize the physical properties of the magnetic-MIPs. The µ-SPE was then optimized using one variable at a time approach to enhance the extraction efficiency. Under the optimal extraction conditions, the feasibility of using magnetic-MIPs as the adsorbents for the extraction of the selected PAHs was proven with a wide linearity range (5-250 µg L-1), good repeatability (relative standard deviation <10%), ultra-trace detection limits (0.01-0.02 µg L-1) and good relative recovery (80.2-119.3%) for the application in the environmental water. The doubt of using the µ-SPE was investigated by calculating the measurement uncertainty. The estimated combined standard uncertainties for the determination of the selected PAHs were in the range of 0.0678-0.0890. It was concluded that the uncertainty of the µ-SPE-µ-HPLC-UV is mainly attributed to its accuracy. Nevertheless, the results showed that the measurement uncertainty of the proposed magnetic-MIPs-based µ-SPE-µ-HPLC-UV was at an acceptable level. The method is beneficial to the routine analysis, especially in providing simple and sensitive determination of the selected PAHs in environmental water. The µ SPE technique consumes minimal amounts of solvent and traces of adsorbents, which then greatly minimizes the waste and analysis costs in routine analysis. (author)

[en] Amlodipine and nifedipine, both widely used calcium channel blockers (CCBs) for hypertension treatment, have emerged as environmental contaminants in water sources such as lakes, rivers, and oceans due to inadequate effluent treatment. In this study, activated carbon derived from peanut shell waste was utilized in magnetic solid-phase extraction (m-SPE) to determine the presence of amlodipine and nifedipine in water samples. A Plackett-Burman and central composite design were employed to assess the effects of seven parameters: pH, temperature, activated carbon weight, stirring speed, contact time, volume of water sample and desorption solvent. Optimal m-SPE conditions were established as follows: pH 11, water temperature 90°C, stirring speed 500 rpm, contact time 11 minutes, and 1.25 g of activated carbon. High-performance liquid chromatography (HPLC) with a diode array detector was used for the final quantification of the target drugs. The extraction method demonstrated excellent linearity (r² = 0.994) and low limits of detection (LOD) and quantification (LOQ), with LODs of 1.04 ng/mL for amlodipine and 1.13 ng/mL for nifedipine, and LOQs of 3.40 ng/mL for amlodipine and 3.48 ng/mL for nifedipine. Recovery rates ranged from 80% to 98% across three concentration levels. Repeatability analysis indicated satisfactory intra-day and inter-day relative standard deviation below 6%. Regeneration studies on adsorbent performance showed recovery loss rates below 15% after four cycles. Additionally, the m-SPE method was environmentally sustainable, with an overall AGREEnness score of 0.71, Blue Applicability Grade Index (67.5), and Sample Preparation Metric Sustainability (7.47) underscoring its green credentials. (author)

[en] Perfluorooctane sulfonate (PFOS) has been classified as a persistent organic pollutant that contributes to water pollution due to its slow environmental degradation properties. Due to the need for effective removal of PFOS from polluted water bodies, a supramolecular hydrogel incorporating sodium alginate and β-cyclodextrin (SA-β-CD hydrogel) was developed to facilitate the entrapment of PFOS. The adsorption study has been utilised to remove PFOS via batch experiment procedure on several adsorptive parameters such as pH, contact time and initial concentration. The optimum conditions with a dose of 1280 mg of SA-β-CD hydrogels beads were applied at 70°C, contact time of 30 minutes, pH of 5.5, 10 mL of 10.0 ppm of PFOS solution, and 250 rpm of stirring rate were reported. The adsorption capacity and efficiency removal of PFOS by SA-β-CD hydrogel beads has achieved up to 0.0764 mg/g and 84.72%, respectively. Based on the data obtained, the adsorption kinetic study, which follows a pseudo-second-order model, was fitted to illustrate the adsorption of PFOS by SA-β-CD hydrogel beads, with an R² value of 0.990. The adsorption isotherm study showed that the adsorption of PFOS by SA-β-CD hydrogel beads fits the Langmuir isotherm model, with an R² value of 0.987. The adsorption of PFOS occurs as a monolayer/single layer and involves chemisorption to the hydrogel beads. Therefore, this work demonstrates that SA-β-CD hydrogel beads may be useful in controlling environmental water pollution. (author)