Penentuan Plumbum Menggunakan Kaedah Analisis Suntikan Aliran Berdasarkan Pembentukan Kompleks antara Plumbum dengan Reagen Galosianin

Flow injection analysis (FIA) with UV-Visible detection has been used in this study for Pb(II) detection in an aqueous environment. The FIA system used in this study was based on the reaction between Pb (II) and gallocyanine which formed a complex with maximum absorbance at around 550 nm. The carrier solution flow rate, solution pH and the reagent concentration have been optimised to increase the efficiency of the FIA system. The FIA system was found to be optimum at 1.2 mL/min flow rate and pH 8. The dynamic range for the Pb(II) concentration was found to be between 1.0 x 1([3 mg/L and 1.0 x lOt mg/L. The reproducibility of the method was very good with RSD value of 1.03 %. At mole ratio of 1:1, Cd(II) , Ni(II) and Co(II) were found to interfere with respective relative error of 10.05 %, 10.15 % and 10.25 %

Spectrophotometric determination of trace Arsenic (III) ion based on complex formation with gallocyanine

In this study, a simple, selective and sensitive method, for spectrophotometric determination of As(III) with gallocyanine as the sensitive reagent was developed. The wavelength of an analytical measurement, for the determination of As (III), using gallocyanine was at 630nm with an optimum response at pH 2. The RSD for the reproducibility of 100 ppm As(III) was 2.3%. The LOD was 0.04 ppm with linear dynamic range in As(III) concentration of 0.2 - 1.5 ppm. The developed method has been validated against Atomic AbsorptionSpectrophotometry (AAS). The interference study of several metal ions was carried out andit revealed that that Mn (II) ion was interfered the most

Electrochemical characteristic of Biotinyl Somatostatin- 14/Nafion modified gold electrode in development of sensor for determination of Hg(II)

Electrochemical sensor for Hg(II) has been developed using Biotinyl Somatostatin-14 peptide modified gold electrode utilizing nafion as the immobilizing agent. Experimental conditions such as pH, supporting electrolyte and scan rate were optimized. Detection of mercury using Biotinyl Somatostatin-14 peptide/Nafion has been observed to be optimum under acidic conditions. Good relative standard deviation of 3.7% has been obtained indicating reliability of the detection system. A linear calibration plot in the range of 40-170 µgL-1 was obtained with sensitivity value of 1×10-10 AµM-1. Limit of detection (LOD) obtained is 0.4 µgL-1 which is below the WHO guidelines for drinking water. The scan rate study showed that the process is a complex surface process, mostly involving an adsorption process. This developed method was applied for determination of Hg(II) in actual waste water samples and a good agreement was obtained between the proposed method and ICP-MS based on the analysis of the waste water samples

Generalised additive model of DIR based on region, monsoon and state in Peninsular Malaysia

A generalised additive model (GAM) framework for dengue incidence rate (DIR) as a response in Peninsular Malaysia for three areas which as region, monsoon and state has been adopted in this study. A spatio-temporal series of 1296 observations with the following explanatory variables; state, latitude and longitude of state capital, land area of state, year, month, total dengue cases, estimated state population pertaining to the year, population density of state, maximum, minimum and average monthly rainfall, maximum, minimum and average monthly temperature, monthly number of rainy days and Nino 4. Result presents three basis model with statistically significant explanatory variables consist of mean rainfall (current month and lag 3-month), mean temperature (current month and lag 1-month), number of rainy day (current month and lag 3-month), Nino 4 (lag 6-month), DIR (lag 3-month) and interaction between temperature lag 1-month and Nino 4 (lag 6-month), population, population density, year, month, monsoon area, state and region. Model 1, Model 2 and Model 3 with the lowest deviance, AIC and BIC are the best models of DIR that successfully developed for three areas mentioned

Development of electrochemical sensor for detection of mercury by exploiting His-Phe-His-Ala-His-Phe-Ala-Phe modified electrode.

A sensitive voltammetric method for detection of mercury ions is described which is made by modifying a gold electrode with 3-mercaptopropionic acid followed by covalent attachment of the octapeptide His-Phe-His-Ala-His-Phe-Ala-Phe to the self-assembled monolayer using carbodiimide coupling. A linear working range for concentration of mercury between 0.25 to 0.81 with LOD 9.5×10 -9 M was obtained which is below the WHO guidelines for drinking water. The reproducibility of the analytical signal is 4.5% in indicating a reproducible and reliable detection system. The developed method was applied for the detection of Hg(II) in spiked wastewater and validated against ICPMS. Good agreement was obtained between the developed method and ICPMS. Insignificant interference was observed by As 3+, Cr 3+, Cu 2+, Ni 2+, Pb 2+and Zn 2+ in detection of Hg(II) thus making the developed system highly potential for electrochemical sensor in Hg(II) detection

Direct photometric determination of lead by manual and flow injection methods with gallocyanine

A direct photometric method was developed for the determination of sub-nanogram levels of lead. The method is based on complexation between lead and gallocyanin, which form a coloured dye (λmax 550 nm) at pH 8.0. The determination was based on the use of kinetic approach and in the lead concentration range of 1.0 × 10-3 μg/mL to 1.0 × 101 μg/mL, a smooth calibration curve was obtained. The reaction system can also be successfully adapted to flow injection analysis (FIA). The dynamic range of the proposed flow injection method was 1.0 × 10-3 μg/mL to 1.0 × 102 μg/mL and detection limit was 1.6 ng/mL at a sampling rate of 30 injections per hour. At 1:1 mole ratio of lead to the interfering ion, mercury, iron, aluminium, citrate and fluoride were found to interfere most during the determination

Optical test strip for trace Hg(II) based on doped sol-gel film.

Optical test strip based on the use of Br-PADAP as a sensitive reagent immobilised into sol–gel thin film for detection of Hg(II) in aqueous solution had been thoroughly carried out. It has a square-sensing zone (1.0 cm × 1.0 cm) containing the sensitive reagent necessary to produce response to trace level of mercury. This method offer sensitivity and simplicity in detecting Hg(II) as no prior treatment or extraction is required. A linear response was attained in the Hg(II) concentration in the range of 0.5–2.5 ppm with calculated limit of detection of 6.63 ppb. This method also showed a reproducible result with relative standard deviation (R.S.D.) of 2.15% and response time of ∼5 min. Interference studies showed that Al(III), Co(II) and Ni(II) significantly interfered during the determination. The developed sensor has been validated against Atomic Absorption Spectroscopy method and proven comparable