Percorrer por autor "Nacapricha, Duangjai"
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- Determination of total phenolic content in wines using Folin-Ciocalteu assay in flow injection analysis systemPublication . Wongpakdee, Thinnapong; Vidigal, Susana S. M. P.; Nacapricha, Duangjai; Rangel, António O. S. S.
- Flow-based method for the determination of biomarkers urea and ammoniacal nitrogen in salivaPublication . Thepchuay, Yanisa; Costa, Carolina F F A; Mesquita, Raquel B R; Sampaio-Maia, Benedita; Nacapricha, Duangjai; Rangel, António O. S. S.Salivary urea and ammonium levels are potential biomarkers for chronic kidney disease. A fast and efficient assessment of these compounds in the saliva of healthy and diseased individuals may be a useful tool to monitor kidney function. Materials & methods: Ammonium ions were measured with an ammonia selective electrode after conversion to ammonia gas. A urease reactor was incorporated in the manifold to hydrolyze urea to ammonium, thereby providing values of ammonia from both urea and ammonium ions in the sample. The accuracy of the method was assessed by comparison with a commercially available kit for urea and ammonium determination. Conclusion: A sequential injection method for the biparametric determination of salivary urea and ammonium employing a single sequential injection manifold was successfully applied to samples collected from both healthy volunteers and chronic kidney disease patients.
- Micro-PAD card for measuring total ammonia nitrogen in salivaPublication . Thepchuay, Yanisa; Mesquita, Raquel; Nacapricha, Duangjai; Rangel, António O. S. S.This work presents a portable microfluidic paper-based analytical device (micro-PAD) card for the quantification of total ammonia nitrogen in human saliva. The amount of total ammonia nitrogen in saliva can be an indicator of the status of the oral microbiome with potential correlation to kidney health problems. The developed micro-PAD card comprises twenty units consisting of three stacked layers of circular discs: the sample layer, paper discs impregnated with sodium hydroxide solution, the PTFE membrane layer, and the detection layer, paper discs impregnated with bromothymol blue. The twenty units were aligned on transparent laminating pouches laminated to form the micro-PAD card (7.5 cm × 10.5 cm). Saliva samples can be directly dispensed onto the micro-PAD card and the detection was achieved by the BTB indicator color change, from yellow to blue, after conversion of ammonium into ammonia and diffusion of the ammonia gas through a hydrophobic layer. The determination of total ammonia nitrogen in saliva using the developed micro-PAD card intended to be very simple method and operated without the need of laboratory equipment. A quantification limit of 11.3 NH4+mg L-1 and linear application range from up to 150 NH4+mg L-1 were obtained making it suitable for the expected concentrations of total ammonia nitrogen in human saliva. It was successfully applied to saliva samples and its validation obtained by comparison against a potentiometric method. The card is stable for at least 1 month making it ideal as a portable device for point-of-care diagnosis.
- Microfluidic paper-based analytical device (µPAD) for salivar ammonia/ammoniumPublication . Thepchuay, Yanisa; Mesquita, Raquel B. R.; Nacapricha, Duangjai; Rangel, António O. S. S.
- Microfluidic Paper-based Analytical Devices (μPADs) for the Determination of Total Ammonia Nitrogen in SalivaPublication . Thepchuai, Yanisa; Mesquita, Raquel B. R.; Nacapricha, Duangjai; Rangel, António O. S. S.
- Sequential flow injection analysis with potentiometric detection for the determination of ammonium and urea in human salivaPublication . Thepchuay, Yanisa; Mesquita, Raquel B. R.; Nacapricha, Duangjai; Rangel, António O. S. S.