Md. Pauzi Abdullah

Extraction of polycyclic aromatic hydrocarbons from contaminated soil using Soxhlet extraction, pressurised and atmospheric microwave-assisted extraction, supercritical fluid extraction and accelerated solvent extraction

Soxhlet extraction has been compared with pressurised and atmospheric microwave-assisted extraction, accelerated solvent extraction and supercritical fluid extraction for the extraction of polycyclic aromatic hydrocarbons (PAHs) from native, contaminated soil. The results indicate that the recovery of PAHs is dependent on the extraction technique. The highest recoveries of individual PAHs were consistently obtained by Soxhlet extraction. For the samples investigated here the preferred technique in terms of recoveries is Soxhlet extraction.

Improved method for the determination of glyphosate in water

Abstract A method for the determination of glyphosate (Glyph) and its metabolite aminomethylphosphonic acid (AMPA) in environmental water was developed with the emphasis on the clean-up procedure. The organic compounds in the environmental water were extracted with dichloromethane and the sample was concentrated by rotary evaporation. The concentrated sample was then passed through a strong anion-exchange (SAX) cartridge with an additional 2 ml of resin in the hydroxide form packed above the SAX packing. Glyph and AMPA were eluted with citrate buffer at pH 5.00 and determined directly by high-performance liquid chromatography with a postcolumn reactor and fluorescence detector. The detection limit and average recovery for both components were 85%, respectively.

Multi-residue analytical methodology-based liquid chromatography-time-of-flight-mass spectrometry for the analysis of pharmaceutical residues in surface water and effluents from sewage treatment plants and hospitals.

An analytical method that facilitated the analysis of 11 pharmaceuticals residue (caffeine, prazosin, enalapril, carbamazepine, nifedipine, levonorgestrel, simvastatin, hydrochlorothiazide, gliclazide, diclofenac-Na, and mefenamic acid) with a single pre-treatment protocol was developed. The proposed method included an isolation and concentration procedure using solid phase extraction (Oasis HLB), a separation step using high-performance liquid chromatography, and a detection procedure that applies time-of-flight mass spectrometry. The method was validated for drinking water (DW), surface water (SW), sewage treatment plant (STP) influent and effluent, and hospital (HSP) influent and effluent. The limits of quantification were as low as 0.4, 1.6, 5, 3, 2.2 and 11 ng/L in DW, SW, HSP influent and effluent, STP effluent, and STP influent, respectively. On average, good recoveries higher than 75% were obtained for most of the target analytes in all matrices. Matrix effect was evaluated for all samples matrices. The proposed method successfully determined and quantified the target compounds in raw and treated wastewater of four STPs and three hospitals in Malaysia, as well as in two SW sites. The results showed that a number of the studied compounds pose moderate to high persistency in sewage treatment effluents as well as in the recipient rivers, namely; caffeine, simvastatin, and hydrochlorothiazide. Ten out of 11 compounds were detected and quantified in 13 sampling points. Caffeine was detected with the highest level, with concentrations reaching up to 9099 ng/L in STP influent.

Inventory of heavy metals and organic micropollutants in an urban water catchment drainage basin

The Linggi River drainage basin in Negeri Sembilan Malaysia is the major source of potable water for the townships of Seremban and Port Dickson. Water quality is threatened by industrial and commercial development taking place in the basin. This study investigated the concentrations and distribution of organic micro-pollutants and heavy metals within the catchment. Arsenic, copper, cadmium, lead, mercury and zinc were determined in water and sediment samples. All heavy metal concentrations were increased down the basin; arsenic and copper concentration in particular were elevated probably due respectively to flow in of arsenical herbicides in rubber and oil palm plantations and copper sulphate and an additive in pig food.Total phenol concentration also increased considerably within the catchment as a result of urbanisation. Five priority phenolic pollutants (2,4-dimethylphenol; 4-chloro-3-methylphenol; 2,4,6-trichlorophenol; 4-introphenol; pentachlorophenol) were found.

Detection of heavy metals in water in Negeri Sembilan, Malaysia: From source to consumption

Drinking water should be free from harmful levels of impurities, such as heavy metals. The aim of this study is to investigate the heavy metals concentrations in a water reticulation system of Negeri Sembilan. 25 stations were selected along Sungai Linggi (upstream of intake point) and through there reticulation system of Sungai Linggi Water Treatment Plant encompassing raw water through to the last point of use. Sampling activities were carried out in June and July 2016. The samples taken were analysed for heavymetals using an Inductively Coupled Plasma – Optical Emission Spectrometer (ICP-OES). In addition other water quality parameters were measured in situ (pH, water temperature, conductivity and dissolved oxygen) and analysed in the laboratory (BOD, COD, TSS, NH3–N, TOC and residual chlorine). The results showed a high level of Ca in the distribution system, while in the treatment plant it was normal, as well as Fe is decreased. Meanwhile Mn is decreased after treatment processes. The concentrations of DO and temperature in the tap water exceeded the standard concentrations.Drinking water should be free from harmful levels of impurities, such as heavy metals. The aim of this study is to investigate the heavy metals concentrations in a water reticulation system of Negeri Sembilan. 25 stations were selected along Sungai Linggi (upstream of intake point) and through there reticulation system of Sungai Linggi Water Treatment Plant encompassing raw water through to the last point of use. Sampling activities were carried out in June and July 2016. The samples taken were analysed for heavymetals using an Inductively Coupled Plasma – Optical Emission Spectrometer (ICP-OES). In addition other water quality parameters were measured in situ (pH, water temperature, conductivity and dissolved oxygen) and analysed in the laboratory (BOD, COD, TSS, NH3–N, TOC and residual chlorine). The results showed a high level of Ca in the distribution system, while in the treatment plant it was normal, as well as Fe is decreased. Meanwhile Mn is decreased after treatment processes. The concentrations ...

Determination of human pharmaceuticals in pre- and post-sewage treatment

In this present work, an analytical method based on solid phase extraction (SPE) followed by liquid chromatography-time-of-flight mass spectrometry (LC-TOF-MS) in positive electrospray ionisation mode was successfully applied to real samples for the determination of human pharmaceuticals in pre- and post-sewage treatment samples. The ten target compounds selected in this study include acetaminophen, theophylline, caffeine, metoprolol, sulfamethoxazole, carbamazepine, prednisolone, ketoprofen, norgestrel and simvastatin. Acetaminophen, theophylline and caffeine were present at all five raw sewage samples. In addition, this work provides the first report on the investigation and detection of theophylline in sewage treatment plant (STP) samples in Malaysia.