Pauzi Abdullah

Development of extraction procedure for determination of mercury species using SPME-assisted dispersive derivative agent

The extraction procedure for determination of low level mercury using solid phase microextraction was successfully carried out. Design of experimental works using factorial design and central composite design were applied to screen and predict the optimum condition for extraction step. In this study, variables namely concentration level (5 % m/v) and volume of derivatization solution (150 µL) has depicted as main effect for controlling the suitability of derivative reagent condition. Maximum of signal response (account as total peak areas for mercury species) was obtained when extraction procedure was set up at pH of water sample (5.8), extraction time (14 min), extraction temperature (43 °C) and stirring rate (450 rpm). Reducing time required to reach equilibrium is new improvement achieved in this study. Detection limit for each species (MeHg 26.17 ngL−1; EtHg 48.84 ngL−1 and IHg 14.11 ngL−1) was calculated lower than our previous work. Recovery, repeatability and reproducibility trial were recorded var...

Detection of pesticides residues in water samples from organic and conventional paddy fields of Ledang, Johor, Malaysia

Pesticides have been used extensively by the farmers in Malaysia during the last few decades. Sixteen water samples, collected from paddy fields both organic and conventional, from Ledang, Johor, were analyzed to determine the occurrence and distribution of organochlorine (OCPs) and organophosphorus (OPPs) pesticide residues. GC-ECD instrument was used to identify and determine the concentrations of these pesticide residues. Pesticide residues were detected in conventional fields in the range about 0.036-0.508 µg/L higher than detected in organic fields about 0.015-0.428 µg/L. However the level of concentration of pesticide residues in water sample from both paddy fields are in the exceed limit for human consumption, according to European Economic Commission (EEC) (Directive 98/83/EC) at 0.1 µg/L for any pesticide or 0.5 µg/L for total pesticides. The results that the organic plot is still contaminated with pesticides although pesticides were not use at all in plot possibly from historical used as well as...

Spectroscopic studies of carboxymethyl chitosan-ammonium triflate (NH4CF3SO3) based solid polymer electrolytes

Carboxymethyl chitosan is the promising material to be used as host polymer for solid polymer electrolyte application. The film has been prepared by solution casting technique with different weight percentage of ammonium triflate (NH4CF3SO3) added to carboxymethyl chitosan. The highest ionic conductivity achieved by carboxymethyl chitosan with 20 wt. % of NH4CF3SO3 was 8.90 × 10−6 S cm−1. Fourier transform infrared spectroscopy had been used to examine the effect of ammonium triflate salt on each functional group of carboxymethyl chitosan. The shifting of wavenumber for hydroxyl, carbonyl and ether groups prove there are interaction between ammonium triflate salts and polymer host. The film is electrochemically stable up to 0.8 V.