Nor Kartini Abu Bakar

Speciation of heavy metals by modified BCR sequential extraction procedure in different depths of sediments from Sungai Buloh, Selangor, Malaysia

The sequential extraction procedure proposed by the European Standard, Measurements and Testing (SM&T) program, formerly the Community Bureau of Reference (BCR), was applied for partitioning of heavy metals (HMs) in river sediments collected along the course of Sungai Buloh and the Straits of Malacca in Selangor, Malaysia. Eight elements (V, Pb, Cd, Cr, Co, Ni, Cu and Zn) from seven stations (S1-S7) and at different depths were analyzed using the modified BCR Sequential Extraction Procedure (SEP) in combination with ICP-MS to obtain the metal distribution patterns in this region. The results showed that heavy metal contaminations at S2 and S3 was more severe than at other sampling sites, especially for Zn, Cu, Ni and Pb. Nevertheless, the element concentrations from top to bottom layers decreased predominantly. The samples from the Straits of Malacca (S4-S7) the highest contamination factors obtained were for Co, Zn and Pb while the lowest were found for V and Cr, similar to Sungai Buloh sediments. The sediments showed a low risk for V, Cr, Cu and Pb with RAC values of less than 10%, but medium risk for Co, Zn (except S3), Cd at S1 and S2 and Ni at S1, S3 and S5. Zn at S3 and Cd at S3-S7 showed high risk to our sediment samples. There is not any element of very high risk conditions in the selected samples.

Bio-oils from Pyrolysis of Oil Palm Empty Fruit Bunches

Problem Statement: The palm oil industry generates an abundance of oil palm biomass such as the mesocarp fibre, shell, empty fruit bunch (EFB), frond, trunk and palm oil mill effluent (POME). For 80 million tonnes of fresh fruit bunch (FFB) processed last year, the amount of oil palm biomass was more than 25 million tones. The objectives of this study were to: (i) Determine the effect of various pyrolysis parameters on product yields and (ii) Characterise liquid product obtained under different condition. Approach: In this study, pyrolysis of oil palm Empty Fruit Bunches (EFB) was investigated using quartz fluidized fixed bed reactor. The effects of pyrolysis temperatures, particle sizes and heating rates on the yield of the products were investigated. The temperature of pyrolysis and heating rate were varied in the range 300-700 °C and 10-100 °C min 1 respectively. The particle size was varied in the range of <90, 91-106, 107-125 and 126-250 µm. The elemental analysis and calorific value of the bio-oil were determined. The chemical composition of the oil was investigated using chromatographic and spectroscopic techniques. Results: Under the experimental conditions, the maximum bio-oil yield was 42.28% obtained at 500 oC, with a heating rate of 100 oC min -1 and particle size of 91-106 µm. The calorific values of bio-oil ranged from 20-21 MJ kg -1 . A great range of functional groups of phenol, alcohols, ketones, aldehydes and carboxylic acids were indicated in FTIR spectrum. Conclusion: The chemical characterisation results showed that the bio-oil obtained from oil palm EFB maybe a potentially valuable source as fuel or chemical feedstocks.

Multi-residue analysis of pharmaceutical compounds in wastewaters by dual solid-phase microextraction coupled to liquid chromatography electrospray ionization ion trap mass spectrometry

The aim of this article is to present a new procedure based on dual solid-phase microextraction (dSPME) for the simultaneous extraction of 16 pharmaceutical compounds with acidic and basic characteristics in urban wastewaters. Water samples are divided into two aliquots of 2 mL each extracted by two CW-TPR fibers at different pH values (pH 3 and 11) and with a NaCl concentration of 300 g L(-1) at 75 degrees C for 30 min. The analytes in both fibers are desorbed one after the other in the desorption chamber in static mode with mobile phase for 10 min. The extracts are injected into an LC system coupled to an ion trap mass spectrometer, leading to the accurate quantification of 16 pharmaceutical compounds in wastewaters, in MS(2) mode. All the target compounds found in wastewaters provide good signals corresponding to the protonated precursor ion [M+H](+). The parameters influencing adsorption and desorption of the analytes on fiber were optimized. The assessment of the analytical method was performed by studying the linearity (LOQ to 10 ng mL(-1)) and the intra- and interday accuracy (89.2-109.7%) and precision (RSD <13.6%). The quantification limits obtained ranged between 0.005 and 0.05 microg L(-1). The application of the method to real samples proves its effectiveness in identifying and detecting naproxen, valsartan, bezafibrate, torasemide, diclofenac, carbamazepine, citalopram, lorazepan, fluoxetine, imipramine and amitriptyline in influent and effluent wastewater treatment plant samples.

Low temperature followed by matrix solid-phase dispersion-sonication procedure for the determination of multiclass pesticides in palm oil using LC-TOF-MS

A simple and effective multiresidue method based on precipitation at low temperature followed by matrix solid-phase dispersion-sonication was developed and validated to determine dimethoate, malathion, carbaryl, simazine, terbuthylazine, atrazine and diuron in palm oil using liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS). Liquid-liquid extraction (LLE) followed by low temperature method were optimized by studying the effect of type and volume of organic solvent (acetonitrile, acetonitrile:n-hexane (3:2 v/v) and acetone) and time of freezing to obtain high recovery yield and low co-extract fat residue in the final extract. The optimal conditions for matrix solid-phase dispersion (MSPD) were obtained using 5 g of palm oil, 2 g of primary secondary amine (PSA) as dispersing sorbent, 1 g of graphitized carbon black (GCB) as clean-up sorbent and 15 mL of acetonitrile as eluting solvent under conditions of 15 min ultrasonication at room temperature. Method validation was performed in order to study sensitivity, linearity, precision, and accuracy. Average recoveries at three concentration levels (25, 50 and 100 μg kg(-1)) were found in the range of 72.6-91.3% with relative standard deviations between 5.3% and 14.2%. Detection and quantification limits ranged from 1.5 to 5 μg kg(-1) and from 2.5 to 9 μg kg(-1), respectively.

Comparative study on open system digestion and microwave assisted digestion methods for metal determination in shrimp sludge compost

The aim of this work was to evaluate two different digestion methods for the determination of the total concentration of metals (Zn, Cu, Cr, Ni, Pb and Cd) in shrimp sludge compost. The compost made from shrimp aquaculture sludge co-composted with organic materials (peat, crushed bark and manure) was used as an organic growing medium for crop. Open system digestion and microwave assisted digestion procedures were employed in sample preparation. Various combinations and volumes of hydrofluoric, nitric and hydrochloric acids were evaluated for the efficiency of both methods. A certified reference material (CRM 146) was used in the comparison of these two digestion methods. The results revealed a good agreement between both procedures and the certified valued. The best recoveries were found in the range between 95% and 99% for microwave assisted digestion with a mixture of 2 ml of HF, 6 ml of HNO(3) and 2 ml of HCl. This procedure was recommended as the method for digestion the compost herein based on the recovery analysis and time taken.

The chemical speciation of zinc in human saliva: possible correlation with reduction of the symptoms of the common cold produced by zinc gluconate-containing lozenges.

This work attempts to correlate the effectiveness of treatment with zinc gluconate lozenges in reducing the symptoms of common colds as measured in seven double-blind clinical trials in 648 volunte...

Comparative study of different clean-up techniques for the determination of λ-cyhalothrin and cypermethrin in palm oil matrices by gas chromatography with electron capture detection.

Solid phase extraction (SPE) and dispersive solid-phase extraction (d-SPE) were compared and evaluated for the determination of λ-cyhalothrin and cypermethrin in palm oil matrices by gas chromatography with an electron capture detector (GC-ECD). Several SPE sorbents such as graphitised carbon black (GCB), primary secondary amine (PSA), C(18), silica, and florisil were tested in order to minimise fat residues. The results show that mixed sorbents using GCB and PSA obtained cleaner extracts than a single GCB and PSA sorbents. The average recoveries obtained for each pesticide ranged between 81% and 114% at five fortification levels with the relative standard deviation of less than 7% in all cases. The limits of detection for these pesticides were ranged between 0.025 and 0.05 μg/g. The proposed method was applied successfully for the residue determination of both λ-cyhalothrin and cypermethrin in crude palm oil samples obtained from local mills throughout Malaysia.

Chemical speciation and bioavailability of rare earth elements (REEs) in the ecosystem: a review

Rare earths (RE), chemically uniform group of elements due to similar physicochemical behavior, are termed as lanthanides. Natural occurrence depends on the geological circumstances and has been of long interest for geologist as tools for further scientific research into the region of ores, rocks, and oceanic water. The review paper mainly focuses to provide scientific literature about rare earth elements (REEs) with potential environmental and health effects in understanding the research. This is the initial review of RE speciation and bioavailability with current initiative toward development needs and research perceptive. In this paper, we have also discussed mineralogy, extraction, geochemistry, analytical methods of rare earth elements. In this study, REEs with their transformation and vertical distribution in different environments such as fresh and seawater, sediments, soil, weathering, transport, and solubility have been reported with most recent literature along key methods of findings. Speciation and bioavailability have been discussed in detail with special emphasis on soil, plant, and aquatic ecosystems and their impacts on the environment. This review shows that REE gained more importance in last few years due to their detrimental effects on living organisms, so their speciation, bioavailability, and composition are much more important to evaluate their health risks and are discussed thoroughly as well.

A Comparative Study of Selected Trace Element Content in Malay and Chinese Traditional Herbal Medicine (THM) Using an Inductively Coupled Plasma-Mass Spectrometer (ICP-MS).

A total of 60 products of traditional herbal medicine (THM) in various dosage forms of herbal preparation were analyzed to determine selected trace elements (i.e., Zn, Mn, Cu, Cd, and Se) using ICP-MS. Thirty types of both Chinese and Malay THMs were chosen to represent each population. The closed vessel acid microwave digestion method, using CEM MARS 5, was employed for the extraction of the selected trace elements. The digestion method applied was validated by using certified reference material from the Trace Element in Spinach Leaves (SRM1570a). The recoveries of all elements were found to be in the range of 85.3%–98.9%. The results indicated that Zn, Mn, Cu, Cd and Se have their own trends of concentrations in all samples studied. The daily intake concentrations of the elements were in the following order: Mn > Zn > Cu > Se > Cd. Concentrations of all five elements were found to be dominant in Chinese THMs. The essentiality of the selected trace elements was also assessed, based on the recommended daily allowance (RDA), adequate intake (AI) and the United States Pharmacopeia (USP) for trace elements as reference. The concentrations of all elements studied were below the RDA, AI and USP values, which fall within the essential concentration range, except for cadmium.

Determination of polar aromatic amines using newly synthesized sol-gel titanium (IV) butoxide cyanopropyltriethoxysilane as solid phase extraction sorbent

A solid phase extraction (SPE) method has been developed using a newly synthesized titanium (IV) butoxide-cyanopropyltriethoxysilane (Ti-CNPrTEOS) sorbent for polar selective extraction of aromatic amines in river water sample. The effect of different parameters on the extraction recovery was studied using the SPE method. The applicability of the sorbents for the extraction of polar aromatic amines by the SPE was extensively studied and evaluated as a function of pH, conditioning solvent, sample loading volume, elution solvent and elution solvent volume. The optimum experimental conditions were sample at pH 7, dichloromethane as conditioning solvent, 10 mL sample loading volume and 5 mL of acetonitrile as the eluting solvent. Under the optimum conditions, the limit of detection (LOD) and limit of quantification (LOQ) for solid phase extraction using Ti-CNPrTEOS SPE sorbent (0.01-0.2; 0.03-0.61 µg L(-1)) were lower compared with those achieved using Si-CN SPE sorbent (0.25-1.50; 1.96-3.59 µg L(-1)) and C18 SPE sorbent (0.37-0.98; 1.87-2.87 µg L(-1)) with higher selectivity towards the extraction of polar aromatic amines. The optimized procedure was successfully applied for the solid phase extraction method of selected aromatic amines in river water, waste water and tap water samples prior to the gas chromatography-flame ionization detector separation.