A portable device for estimation of protein concentration through Biuret test

Project Title

A portable device for estimation of protein concentration through Biuret test

Project Area of Specialization Biomedical EngineeringProject Summary

Our main objective is estimation of protein concentration in a given sample of milk by exploiting the relationship between spectral absorptivity and the concentration of protein. We propose to use optical sensors to accurately estimate the concentration of protein in different types of milk. The research objectives under consideration are accuracy, response time, sample size, and portability. We intend to design and fabricate a prototype of a portable spectroscopic device that can determine the concentration of protein within 5 minutes with an accuracy of around 90% in a sample size not greater than 5ml collected from a dairy outlet.

Project Objectives

1. Exploring the relationship between spectral absorptivity and the concentration of protein.
2. Extending the output of Biuret Test from qualitative analysis to quantitative results, under spectrophotometric principle.
3. Analyze the effect of presence of other nutrients (e.g. fats) and other additives on the absorptivity of sample under consideration.
4. Find methods to mullify the effects of fats and other additives, for successful calibration of the protein estimation.
5. Design a portable, cost-effective device for estimation of protein concentration in dairy products (e.g. milk).

Project Implementation Method

Biuret test is the analytical method in which a protein sample is qualitatively analysed i.e. only tests for the presence of protein in a sample. Followed by a series of reactions with sodium hydroxide (NaOH) and copper (II) sulfate (CuSO4), the conjugate molecule of Cu(II) and NH4 gives blue-violet color combinations. We base our work on the fact that the intensity of color is proportional to protein content in sample. The spectral absorptivity analysis of the color variation, based on Beer-Lambert's law, expressed in equation 1, is the key for estimation of protein content.

Where A, ?, c, and l represent absorbance, absorptivity coefficient, concentration of protein in the sample, and path length through sample, respectively.

such that ,  ? =c?  

where T = transmittance

where

as, Io < I

where Io =  is the intensity before transmitted through sample

            I = is the intensity after transmitted  through sample

Table 1 describes an overview to spectroscopic assays under consideration..

Table 1:

Source	Wavelengths	Reagents & Indicators	Output Range	Advantages
Ultra violet absorption	240nm - 280nm	1ml NaOH 2-3 drops copper sulphate (CuS04)	0.1 – 100 ????g/ml	Small sample size, low cost
Visible light absorption	540nm – 560nm	1ml NaOH 2-3 drops copper sulphate (CuS04)	20 - 2000????g/ml	Low variability
Infra Red absorption	700 nm onwards	1ml NaOH 2-3 drops copper sulphate (CuS04)	10  – 1000????g/ml	High sensitivity and precision

Implementation Methodology Flowchart: 

Source

Ultra violet absorption

Visible light absorption

Infra Red absorption

Benefits of the Project

1. A device to estimate protein concentration in a given diary product through Biuret test, extending the qualitative output to quantitative output.
2. Portability, easy to handle
3. Accuracy (90% approx.)
4. Quicker
5. Small sample size (less than 5ml)
6. Wide spectral range analysis (visible, infrared and ultraviolet)
7. Cost effective

Technical Details of Final Deliverable

Chemicals:                  Copper (II) sulfate, Sodium hydroxide

Apparatus:                  Test tubes, Test tube holder, Cuvette, Dropper

Sample Size:               5 ml

Path Length (distance b/w transmitter and receiver):  1 cm

Analysis Mode:           Absorbance Mode

Microcontroller:          Arduino MEGA 2560

                                  (Programmed in C language using Arduino IDE)

Setup Design:

Transmitters/Sensors:

            Table 2 describes an overview to transmitters and sensors...

Table 2:

S No..	Transmitters	Cost (PKR)	Receivers	Cost (PKR)	Output
1.	UV Laser Diode (240-280 nm)	2500/-	UV receiver photodiode	2000/-	Analog Voltage to ADC value
2..	White Light LED (380 - 700 nm)	4000/-	RGB Color sensor (TCS 3200)	1500/-	Frequency modulated output to ADC value
3.	IR Transmitter (850nm/  940 nm)	2500/-	IR receiver photodiode	2200/-	Analog Voltage to ADC value

Output:

• Absorbance    
• Protein Concentration in µg/ml

1.

2..

3.

Final Deliverable of the Project HW/SW integrated systemCore Industry FoodOther Industries Health Core Technology Artificial Intelligence(AI)Other Technologies OthersSustainable Development Goals Good Health and Well-Being for PeopleRequired Resources

S No..	Transmitters	Cost (PKR)	Receivers	Cost (PKR)	Output
1.	UV Laser Diode (240-280 nm)	2500/-	UV receiver photodiode	2000/-	Analog Voltage to ADC value
2..	White Light LED (380 - 700 nm)	4000/-	RGB Color sensor (TCS 3200)	1500/-	Frequency modulated output to ADC value
3.	IR Transmitter (850nm/  940 nm)	2500/-	IR receiver photodiode	2200/-	Analog Voltage to ADC value