potentiometric sensor.pptx

this elaborates about potentiometric sensors and its uses

1. Potentiometric sensors Instrumental analysis and analytical technique 01

2. Table of Contents 03 P rinciple Introduction Advantages Disadvantages Applications Working

3. Sensors: A sensor is a device which is use to detect or sense the minor change in environment and give some output on the other device. 04

4. Types of Sensors: 05

5. A potentiometric sensor is a type of electrochemical sensor that may be used to measure potential difference of an electrode. P otentiometric sensor: 06

6. The signal is measured as the potential difference (voltage) between the working  electrodes  and the reference electrode. The working electrode's potential must depend on the concentration of the analyte in the gas or solution phase. In the potentiometric sensor the ion-selector electrode is coupled with the reference electrode to complete the circuit and the sensor measure the potential difference between two electrode. Principle: 07

7. The potentiometric sensor are used in analysis of glucose in blood. Glucose is converted into ions, which is detected by ion-selective electrode. Glucose is oxidized into gluconic acid which is further undergoes decomposition and gives H+ ions which are detected by pH electrode. Glucose + o 2 glucose oxidase gluconic acid +H 2 O 2 . H 2 O 2 electrode 2H + +O 2 +2e - + ion measured by pH meter, a potential difference is set-up between glass electrode and reference electrode which is sense by potentiometric sensor which analyze the glucose level in blood. Where we use potentiometric sensor: 08

8. The measuring system consists of a Ph. measuring electrode (indicating electrode) and reference electrode. The potential difference between the two electrode is a function of the pH value of the measured solution. pH meter 09

9. Use the potentiometer to determine the difference b/w the potential of two electrode. ( Potentiometery ) Two types of electrode Reference Electrode (fixed potential) Indicator Electrode (Analyte activity) Working 10

10. Types of reference electrodes used; Standard Hydrogen electrode Ag/AgCl electrode Reference Electrode 11

11. Potentiometric solid state gas sensors have been generally classified into three broad groups Type I Type II Type III Classification of sensors 12

12. Type I sensors have an electrolyte containing mobile ions of the chemical species in the gas phase that it is monitoring. The commercial product, YSZ oxygen sensor, is an example of type I. Type I Type II Type II sensors do not have mobile ions of the chemical species to be sensed, but an ion related to the target gas can diffuse in the solid electrolyte to allow equilibration with the atmosphere. 13

13. Type III sensors make the electrode concept even more confusing. With respect to the design of a solid state sensor, the auxiliary phase looks as part of the electrode. Type III 13

14. Potentiometric sensors are broadly used to measure position, displacement , level, motion, pressure, airflow, and many other physical parameters. They are also integrated into other sensors to monitor chemicals, gases, or bio cells. Applications 15

15. Potentiometric pressure sensors 16

16. Potentiometric Airflow sensors 17

17. Potentiometric Gas Sensors 18

18. Potentiometric Biosensors 19

19. Response is very rapid. Simple and low cost. Easy to prepare and use. It is not affected by catalytic poisons. Chemically resistant to oxidizing and reducing agents, dissolved gases, salts , etc… When lithia-silica glasses are used. It can be used over the entire ranges. Advantages 20

20. Extremely fragile Minute abrasions on the surface of the tip, damages the electrode. It cannot be used with simple potentiometers, because of the high resistance. Upper limit of electrode pH is 8. It needs to be used freshly. Disadvantages 21