Colorimeter

A measuring instrument may be a device that’s utilized in colorimetric analysis. It refers to a tool that helps specific solutions to soak up a selected wavelength of sunshine. The measuring instrument is typically wont to live the concentration of a known  matter during a given answer with the assistance of the Beer-Lambert law. The measuring instrument was fabricated within the year 1870 by Louis J Duboscq.

Principle of measuring instrument

It is a measuring technique that states that once a beam of incident lightweight of intensity Io passes through an answer, the subsequent occur:

A part of it’s mirrored that is denoted as Ir

A part of it’s absorbed that is denoted as IA

Rest of the sunshine is transmitted and is denoted because it

Therefore, Io = Ir + Ia + It

To determine the activity of Io and It is enough thus, Ir is eliminated. The quantity of sunshine mirrored is an unbroken constant to live in Io and It.

Colorimeter is predicated on 2 basic laws of measure. We’ve mentioned them below:

Beer’s law:

According to this law the quantity of sunshine absorbed is proportional to the matter concentration given in the answer.

Log10 Io/It = asc

where,

as is permeability index

c is that the concentration of answer

Lambert’s law:

According to this law the quantity of sunshine absorbed is proportional to the length and thickness of the answer taken for analysis.

A = log10 Io/It = asb

Where,

A is that the check absorbance of check

as is the quality absorbance

b is that the length / thickness of the answer

Working of measuring instrument

Step 1: Before beginning the experiment it’s necessary to calibrate the measuring instrument. It’s done by victimizing the quality solutions of the known  matter concentration that must be determined. Fill the quality solutions within the cuvettes and place it within the cuvette holder of the measuring instrument.

Step 2: a light-weight ray of an exact wavelength that is restricted for the assay is within the direction of the answer. the sunshine passes through a series of various lenses and filters. The colored lightweight navigates with the assistance of lenses, and also the filter helps to separate a beam of sunshine into completely different wavelengths, permitting solely the desired wavelength to withstand and reach the cuvette of the quality check answer.

Step 3: once the beam of sunshine reaches’ cuvette, it’s transmitted, reflected, and absorbed by the answer. The transmitted ray falls on the photodetector system wherever it measures the intensity of transmitted light. It converts it into the electrical signals and sends it to the meter.

Step 4: The electrical signals measured by the meter area unit displayed within the digital type.

Step 5: Formula to see substance concentration in check answer.

A = ∈cl

For standard and check solutions

∈ and l area unit constant

AT = CT ….. (i)

AS = CS ….. (ii)

From the higher than 2 equations,

AT × CS = AS × CT

CT = (AT/AS) × cesium

Where,

CT is the check answer concentration

AT is the absorbance/optical density of check answer

CS is the quality concentration

AS is the absorbance / optical density of ordinary answer

Advantages and drawbacks of measuring instrument

Some edges area unit as follows:

It is a reasonable methodology, widely utilized in the measurement of colored samples, simple to hold, and transport.

Some disadvantages are as follows:

Analysis of colourless compounds isn’t potential, doesn’t add IR and UV regions.

Conclusion

Color photometers, which measure transmission and colour reflection, and colour densitometers, which measure the density of primary colours. The Colorimeter is typically used to determine the known solute concentration in a solution using the Beer-Lambert law. In 1870, Louis J Duboscq invented the Colorimeter.