Sample/reagent adsorption on alumina versus Pyrex substrates of microfabricated electrochemical sensors
✍ Scribed by R.S. Diefes; K.Y. Hui; L. Dudik; C.C. Liu; M. Gratzl
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 406 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0925-4005
No coin nor oath required. For personal study only.
✦ Synopsis
Platinum redox sensors have been microfabricated for potentiometric detection in diffusional microtitration of microliter-size fluid samples. Two different materials, alumina ceramic and Pyrex glass, have been studied for their suitability as sensor substrates. Adsorptions of reagent and/or sample on an alumina ceramic substrate and a Pyrex glass substrate are compared. Using iodimetric redox titration, significant adsorption of both reagent and sample occurs on alumina ceramic substrates. This causes contamination and cross-contamination of samples, leading to highly irreproducible results. Reproducibility with a 1.6% coefficient of variation has been achieved using a platinum redox sensor deposited on a Pyrex substrate for the analysis of 20 p,L sample microdroplets. Due to the large surface area relative to the small sample volume, surface processes can have a significant effect on the analysis of microsamples. Therefore, precautions must be taken to minimize problems arising from air interference and sensor/sample, sensor/reagent and reagent/sample interfaces.