Mesquita, Raquel B. R.

Nacapricha, Duangjai

Rangel, António O. S. S.

Thepchuay, Yanisa

English

Repositório Institucional da Universidade Católica Portuguesa

ANALÍTICA 20189th Meeting of Division of Analytical Chemistry26-27 MARCH, PORTO-PORTUGALFFUP/ICBAS – UNIVERSITY OF PORTOBOOK OF  ABSTRACTSwww.analitica2018.eventos.chemistry.pt118 PH 30 MICROFLUIDIC PAPER-BASED ANALYTICAL DEVICE (µPAD) FOR SALIVARY AMMONIA/AMMONIUM Yanisa Thepchuay1,2, Raquel B. R. Mesquita2, Duangjai Nacapricha1, António O. S. S. Rangel21Faculty of Science, Mahidol University, Rama 6 Road, Thungpayathai, Rachathewi, Bangkok, Thailand 10400 2Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, 172, 4202-401 Porto, Portugal rmesquita@porto.ucp.pt A microfluidic paper-based analytical device (µPAD) was developed as a low cost, easy-to-use, disposable sensor for potential quantitative analysis of ammonia in saliva samples. The principle for the determination is based on the colour change of the bromothymol blue (BTB) indicator, produced by a change in pH; it shows a clear colour change from yellow to blue in the transition range of pH 6.0 - 7.6. The colour change was measured by using a desktop scanner and ImageJ software to analyze the recorded image. Preliminary experiments were carried out using direct deployment of ammonia standards in the µPAD. The µPADs size was 75 x 105 mm and contained twenty circular hydrophilic sample zone and detection zone. The effect of indicator concentration was studied in the range from 0.13 – 0.65 mM. A 0.65 mM BTB concentration provided the highest sensitivity of ammonia detection in the linear range of 0 – 150 mg/L: A = (0.10 × 10-3 ± 0.03 ×10-3) x mg/L NH3 – (3.2× 10-3 ± 2.2 ×10-3) (r2 = 0.996). To apply this method to saliva samples, studies are now focused on isolating ammonia from the matrix, using gas-diffusion. Therefore, we are designing a µPADs with 3 layers, consisting of sample zone as the first layer, impregnated with the sodium hydroxide for conversion ammonium to ammonia. The second layer is a polytetrafluoroethylene (PTFE) hydrophobic membrane. It will allow the produced ammonia from sample zone to diffuse and react with BTB reagent at detection zone, which is the third layer. The developed µPADs approach could be useful for making point-of-care device to quantify the level of salivary ammonia/ammonium associated with some oral disease. Acknowledgements: R. B. R. Mesquita thanks for the grant SFRH/BDP/112032/2015. This work was supported by Nationals Funds from FCT – Fundação para a Ciência e Tecnologia through project UID/Multi/50016/2013. 

Microfluidic paper-based analytical device (µPAD) for salivar ammonia/ammonium

https://repositorio.ucp.pt/bitstream/10400.14/24309/1/Thepchuay_PH30_Analitica2018.pdf

Microfluidic paper-based analytical device (µPAD) for salivar ammonia/ammonium

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Repositório Institucional da Universidade Católica Portuguesa