![ Gas effuses through membrane:
CO2 (aq) » CO2 (g) » CO2 (aq)
External membrane internal
Solution pore solution
In internal solution, pH changes:
CO2 (aq) + H2O » HCO3
- + H+
which is detected by ISE probe
Overall reaction:
CO2 (aq) + H2O » H+ + HCO3
-
external internal
solution solution
Eind = c + 0.0592 log [CO2]ext](https://image.slidesharecdn.com/moleculeselectiveelectrodesystemandbio-sensor-211112163705/85/Molecule-selective-electrode-system-and-bio-sensor-3-320.jpg)
Molecule selective electrode system and bio sensor
- 1. SUBMITTED BY MAYUR HARSUKHBHAI MARVANIYA MSc CHEMISTRY(SEM-2) 20MSC01014 GUIDED BY DR.VIRAJ BHANVADIA ASSISTANT PROFESSOR SOS,GSFC UNIVERSITY
- 2. MOLECULAR SELECTIVE ELECTRODE SYSTEM i. Electrodes designed for the detection of molecules instead of ions ii. Gas sensing electrodes (or gas-sensing probes) Typically based on ISE surrounded by electrolyte solution - Activity of ion measured is affected by dissolved gas - Gas enters interior solution from sample by passing through a gas permeable membrane
- 3. Gas effuses through membrane: CO2 (aq) » CO2 (g) » CO2 (aq) External membrane internal Solution pore solution In internal solution, pH changes: CO2 (aq) + H2O » HCO3 - + H+ which is detected by ISE probe Overall reaction: CO2 (aq) + H2O » H+ + HCO3 - external internal solution solution Eind = c + 0.0592 log [CO2]ext
- 4. iii. Enzyme electrodes (or Biocatalytic Membrane Electrodes) -General approach is to use an immobilized enzyme. - Enzyme converts a given molecular analyte into a species that can be measured electrochemically. Examples: H+ pH electrode CO2 CO2 Gas sensing electrode NH3 NH4 + Glass, pH
- 5. Principal: In presence of enzyme urease, urea (NH4)2CO is hydrolyzed to give NH3 and H+ Monitor amount of NH3 produced using NH3 gas sensing electrode (NH4)2CO + 2H2O + H+ » 2NH4 + + HCO3 - » 2NH3 + 2H+
- 6. BIO-SENSOR Introduction • A biosensor is an analytical device which converts the biological signal into a measurable electrical signal. • Professor Leland C Clark is the father of Biosenor. Professor Leland C Clark 1918–2005
- 7. A GOOD BIOSENSOR • It should provide accurate, precise, reproducible results. • It should be free from electrical noise. • It should be cheap, small, portable and capable of being used by semi-skilled operators. • The reaction should be independent from physical parameters ( pH and temperature
- 8. PARTS OF BIOSENSOR • Bio receptors • Transducer • Signal processor
- 9. BIORECEPTOR The bioreceptor is a biologically derived material such as tissue, microorganisms, organelles, cell receptors, enzymes, antibodies, nucleic acids, etc. or Biomimetic component that binds or recognizes the analyte of interest.
- 10. TRANSDUCER When the analyte interacts with the bioreceptor, change in biological signals such as change in temperature, electrical charge occurs. The transducer transforms these signal into another signal which is easily measured and quantified.
- 11. Based on the type of transducer the Bio- sensors classified as Biosensor Calorimetric Optical Amperometric Piezoelectric Potentiometric
- 12. Calorimetric biosensors The heat produced (or absorbed) by the reaction. Potentiometric biosensors Changes in the distribution of charges causing an electrical potential. Amperometric biosensors Movement of electrons produced in a redox reaction. Optical biosensors Light output during the reaction or a light absorbance difference between the reactants and products . Piezo-electric biosensors Effects due to the mass of the reactants or products .
- 13. SIGNAL PROSSESOR Glucose monitoring device (for diabetes patients) Monitor the glucose level in the blood The enzyme glucose oxiadase is used by blood glucose biosensor to break down of blood glucose. First it oxidizes glucose and uses two electrons to reduce the FAD (a component of the enzyme) to FADH2 which in turn is oxidized by the electrode in a number of steps. The resulting current is a measure of the concentration of glucose. In this case, the electrode is the transducer and the enzyme is the bioreceptor.
- 14. APPLICATION There are numerous applications of biosensors with various types. Some of them are used in Monitoring blood glucose level of diabetes patients. Detection of Environmental contamination e.g. the detection of pesticides and heavy metals in river water. Remote sensing of airborne pathogens durining epidemic outbreaks Determining levels of toxic substances before and after bioremediation Routine analytical measurement of folic acid, biotin, vitamin B12 Drug discovery , Protein engineering. Detection of toxic metabolites such as mycotoxins.
- 15. REFERENCE https://en.wikipedia.org/wiki/Biosensor#:~:text=A%20biosensor%20is %20an%20analytical,component%20with%20a%20physicochemical %20detector. https://chem.libretexts.org/Courses/British_Columbia_Institute_of_Te chnology/Chem_2305/03%3A_Electrochemistry/3.02%3A_Potentiom etry/3.2.06%3A_Molecular-Selective_Electrode_Systems https://www.sciencedirect.com/topics/engineering/selective-electrode THANK YOU