Design of portable electronic instrument for detection of urea in milk by fabrication of urea sensor using ZnO nanoparticles

Milk is considered to be a complete food an disconsumed by individuals of all age groups. Urea is added to milk as an adulterant to increase its shelf life and Solid Not Fat (SNF) value. Excess urea consumption is harmful to human beings which results in serious health issues. Hence, there is an utmost necessity of an instrument to detect and quantify the presence of urea content in milk. ZnO nano powder was synthesized using Sol-Gel process and it was coated on a glass substrate in the form of thick film using the Doctor Blade method. The ZnO immobilized with urease enzyme was used as a sensing layer for detection of urea in milk. The fabricated sensor has a sensitivity of 0.6mV/10mg and the designed instrument indicates the presence of urea within the permissible range by corresponding LED.