I would like to fabricate a biosensor for cholesterol detection.I am trying to prepare stock solution of cholesterol by this method (Non-enzymatic electrochemical detection of cholesterol using cyclodextrin functionalized graphene, Biosens. Bioelectron. 63 (2015) 212-217).my problem is by adding cholesterol solution to phosphate buffer, a precipitate in electrochemical cell was found.I do not know what is wrong.
Make stock solution of cholesterol in methanol with higher concentration (200, 250 micro molar), and then pick very little amount (5,10 micro liter) for further dilution with phosphate buffer.
I would suggest that stock solution of cholesterol be made by dissolving the cholesterol in small/ minimum amount of ethyl alcohol. The dilution could then be done by adding phosphate buffer.
I would suggest that stock solution of cholesterol be made by dissolving the cholesterol in small/ minimum amount of ethyl alcohol. The dilution could then be done by adding phosphate buffer.
Cholesterol is really very complicate to solve. We solve it with isopropyl alcohol (stock) and store it in a septum-closed small container for avoiding evaporation. Working standards are made by dilution with phosphate buffer (not the saline one) and a small percentage of surfactant (Triton X-100).
Hi Farzaneh. We made the stock solution by dissolving the cholesterol in a small volume of Triton X-100 by heating slightly and then dilute slowly with phosphate buffer. Final concentration of Triton X-100 should be 1%.
”Designing electrochemical interfaces with functionalized magnetic nanoparticles and wrapped carbon nanotubes as platforms for the construction of high performance bienzyme biosensors”. Analytical Chemistry 83 (2011) 7807 – 7814. Marcos Eguílaz, Reynaldo Villalonga, Paloma Yáñez-Sedeño, José M. Pingarrón
”Gold nanoparticles: Poly(diallyldimethylammonium chloride) – carbon nanotubes composites as platforms for the preparation of electrochemical enzyme biosensors: Application to the determination of cholesterol” Journal of Electroanalytical Chemistry 661 (2011) 171 – 178. M. Eguílaz, R. Villalonga, L. Agüí, P. Yáñez-Sedeño, J.M. Pingarrón