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Papers by Jaroon Jakmunee

Applied Mechanics and Materials, 2016

Analytical Sciences the International Journal of the Japan Society For Analytical Chemistry, 2008

An automated hydrodynamic sequential injection (HSI) system with spectrophotometric detection was... more An automated hydrodynamic sequential injection (HSI) system with spectrophotometric detection was developed. Thanks to the hydrodynamic injection principle, simple devices can be used for introducing reproducible microliter volumes of both sample and reagent into the flow channel to form stacked zones in a similar fashion to those in a sequential injection system. The zones were then pushed to the detector and a peak profile was recorded. The determination of nitrite and nitrate in water samples by employing the Griess reaction was chosen as a model. Calibration graphs with linearity in the range of 0.7 - 40 muM were obtained for both nitrite and nitrate. Detection limits were found to be 0.3 muM NO(2)(-) and 0.4 muM NO(3)(-), respectively, with a sample throughput of 20 h(-1) for consecutive determination of both the species. The developed system was successfully applied to the analysis of water samples, employing simple and cost-effective instrumentation and offering higher degrees of automation and low chemical consumption.

Analytical Sciences, 2016

In this work, a cost-effective and simple-to-prepare label-free electrochemical immunosensor was,... more In this work, a cost-effective and simple-to-prepare label-free electrochemical immunosensor was, for the first time, fabricated by modifying high-quality graphene oxide (GPO) onto a screen-printed carbon electrode (SPCE). The anti-IgG antibody was then covalently immobilized to the carboxylic group anchoring on the surface of GPO particles. Under the optimized condition, our newly developed immunosensor selectively bound to human immunoglobulin G (IgG), a model biomarker, with high sensitivity at a limit of detection of 1.99 ng mL(-1), potentially sensitive enough for IgG detection at the pathophysiological level, and had a linear range of 2.5 to 100 ng mL(-1). The proposed immunosensor also exhibited high reproducibility and regenerability, resulting in no significant change in electrochemical signals from different replicates of the electrode, and a robust electrochemical current after being subjected to alkaline base washing with several cycles. To this end, our immunosensor demonstrates ability as a promising diagnostic tool for clinical assessment.

Analytical Sciences the International Journal of the Japan Society For Analytical Chemistry, Jan 10, 2006

Simple sequential injection analysis systems with DSTD (SIA/DSTD) have been developed. One was em... more Simple sequential injection analysis systems with DSTD (SIA/DSTD) have been developed. One was employed for the study of the effects of the ion contents in solutions to the dynamic surface pressure of ionic surfactants. The results from the studies show the possibility for an alternative simple fast screening, but also a sensitive procedure for water quality determination. Another simple SIA/DSTD system has been demonstrated for the quantification of an anionic surfactant using a single standard calibration.

Journal of Chemical Education, Dec 1, 2007

... W through Gravitational Field-Flow Fractionation Ronald Beckett,* Reshmi Sharma, and Goja And... more ... W through Gravitational Field-Flow Fractionation Ronald Beckett,* Reshmi Sharma, and Goja Andric Department of Chemistry, Water Studies Centre, Monash University, Clayton, Victoria 3800, Australia; *ron.beckett@sci.monash.edu.au ... 6 2 4 2 2 v d w d w vr 8 − (5) ...

A flow injection amperometric method with dialysis sample pretreatment for determination of ascor... more A flow injection amperometric method with dialysis sample pretreatment for determination of ascorbic acid (vitamin C) has been developed. Standard/sample solution (50 μL) was injected into a donor stream (deionized water) via an injection valve. The sample zone was passed through a dialysis unit to separate the analyte from the matrices. The dialysate containing ascorbic acid, in the acceptor stream of 0.1 M phosphate buffer pH 5.6, was flowed to the amperometric detector for current measurement. Ascorbic acid was electrochemically oxidized at glassy carbon electrode giving an anodic peak current proportional to ascorbic acid concentration. A linear calibration graph in range of 50 - 800 mg/L ascorbic acid was obtained. The relative standard deviation of 10 replicate injections was 1.5 % for 50 mg/L of ascorbic acid. A sample throughput of 20 h-1 was achieved. The proposed method was applied to vitamin C tablets and fruit juice samples collected from drug stores, supermarkets and lo...

Maejo international journal of science and technology

An economical ultrasonic-assisted extraction system was developed for the extraction/spectrophoto... more An economical ultrasonic-assisted extraction system was developed for the extraction/spectrophotometric determination of anionic surfactants based on methylene blue method. A low- cost ultrasonic cleaner was employed to enhance extraction efficiency and also to reduce chemical consumption, time and cost of analysis. Optimum conditions for extraction and detection were determined. Extraction time of 30 seconds and a volume ratio of aqueous sample to organic solvent of 8:1 were found to be optimum. Concentrations of methylene blue and Na2SO4 were selected at 10-5 and 10-2 M respectively. Simultaneous parallel extraction of 12 samples could be carried out. Standard solutions of sodium dodecyl sulphate (0.10 mg L-1) were evaluated for reproducibility and the relative standard deviation was found to be 4.8%. The method was applied to the analysis of 7 real water samples. The concentrations of AS were found in the range of 0.054-0.123 mg L-1. The results obtained were compared to those fr...

Telehealth and telemedicine are the approach to provide health care coverage to people in rural a... more Telehealth and telemedicine are the approach to provide health care coverage to people in rural areas or patients who cannot conveniently travel to meet with doctors at a hospital. The telehealth system requires a multidisciplinary collaboration involving various sectors such as telecommunications, information technology, medical experts, hospitals, equipment suppliers and social workers. The advantages of automatic flow based systems in reducing the volume of sample, the analysis cost, the analysis time and the need of having highly trained personnel, make them suitable for use where the healthcare facility budget is inadequate. Therefore, flow based techniques have potential for applications in clinical analysis as part of the telehealth system in the developing countries.

Flow injection sample pretreatment for determination of lead by flame atomic absorption spectroph... more Flow injection sample pretreatment for determination of lead by flame atomic absorption spectrophotometry has been developed. Utilizing an in-valve mini-column, packed with a solid phase extraction resin (Sr.spec TM), lead was preconncentrated and separated from the matrix. The conditions for sorption and desorption of lead were investigated. A 1 M nitric acid solution and 0.005 M EDTA solution of pH 7 were suitable for sorption and desorption step respectively. A concentration efficiency of 11 min -1 was achieved. A linear calibration was obtained for 0.1-5.0 µg Pb and a single standard calibration can be applied. The method has been applied to the determination of lead in certified reference materials, leachates and digests of tin tailing samples. The system allows rapid analysis of very small sample volumes. Lead has toxicity effects to human health. Accordingly, the development of methods for its determination in variuos biological and environmental samples is both necessary and...

Journal of Radioanalytical and Nuclear Chemistry

A flow injection analysis (FIA) system is described for the determination of uranium. The system ... more A flow injection analysis (FIA) system is described for the determination of uranium. The system consists of a microcolumn packed with. U/TEVA.SpecTM, chromatographic resin for on-line sample separation. The eluate is mixed with 4-(2-pyridylazo) resorcinol (PAR). The colored product is continuously monitored spectrophotometrically.

Talanta, 2015

A cost effective flow injection (FI) conductometric system has been developed for determination o... more A cost effective flow injection (FI) conductometric system has been developed for determination of total inorganic nitrogen (TIN). The system is aimed for evaluation of nitrogen nutrient in soil for agricultural application. Inorganic nitrogen compounds were extracted from soil according to the standard method by using potassium chloride solution as an extractant, and the extracted solution was then injected into the FI system. Nitrate and nitrite are converted to ammonium ion by an in-line reduction column packed with a Devarda's alloy. A gas diffusion unit was incorporated into the FI system to separate ammonium ion from other ions in a donor stream by forming ammonia gas that can diffuse through a PTFE membrane to re-dissolve in an acceptor stream. Conductance of the acceptor stream was directly proportional to ammonium ion concentration. Various parameters affecting reduction efficiency of the column, e.g., column diameter, column packing procedure, and column length was investigated and optimized. A linear calibration graph in the range of 2.00-60.00 mg L(-1) N-NH4(+) (y=0.123x+0.039, R(2) =0.997) was obtained with a limit of detection of 0.47 mg L(-1). Sample throughput of 20 samples h(-1) was achieved. The result of developed method was correlated with total Kjeldahl nitrogen (TKN) obtained from the Kjeldahl digestion method. The proposed method could be used as an alternative method to the Kjeldahl method for determination of TIN in soil.