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Uv Calibration

This document outlines procedures for calibrating a UV-visible spectroscopy instrument. It describes three tests: [1] measuring potassium dichromate standards to verify the extraction coefficient is within the specified range, [2] using potassium chloride to ensure stray light absorption is above 2.0 at 200nm, [3] using a toluene in hexane solution to check the instrument's resolution power is at least 1.2 between 269nm and 266nm.

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443 views3 pages

Uv Calibration

This document outlines procedures for calibrating a UV-visible spectroscopy instrument. It describes three tests: [1] measuring potassium dichromate standards to verify the extraction coefficient is within the specified range, [2] using potassium chloride to ensure stray light absorption is above 2.0 at 200nm, [3] using a toluene in hexane solution to check the instrument's resolution power is at least 1.2 between 269nm and 266nm.

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mananrajsahoo
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© © All Rights Reserved
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Calibration of UV visible spectroscopy

A Control of absorbance

60 mg (+/-3) mg potassium di chromate in 1000 ml 0.005 M H2So4

Measuring configuration in the UV key in parameter in the


spectrum mode as followed: -

Measuring mode absorbance


Recording range0 to 3
Wave length range 400 to 200 nM
Slit width (nm) 2
Scan speed Slow

Ensure the H2So4 is placed in the sample compartment to


obstruct the optical path way. Perform base line correction click
on the base line button, after that click on the auto zero button to
take the spectroscopy.

Place K2Cr2O7 solution in the sample holder and the spectrum


with .005 M. H2So4 acid. Reference measured the absorbance
235, 257, 313 and 350 nm.

Calculate the extraction coefficient E as Below: -

%E (`1%, 1CM) = measured absorbance* 10000/weight of


K2Cr2O7

% E value should be 122.9 – 126.2, 142.4 – 145.7, 47.00 – 50.0,


104.2 – 108.2 respectively wavelength.
B Limit of stray light

1.2% w/v KCL solution

Measurement configuration

Measuring mode abs


Recording range 0–3
Wave length 250 – 190 nm
Slit width 2 nm
Scan speed Slow

Place distil water in both cubtte and do base line place KCL
solution in sample holder and measure the spectrum with water
reference.

Specification

The absorbance value should be more than 2 @ 200 nm.

C Resolution power

.02 % V/V solution of toluene in hexane.

Measurement configuration

Measuring mode abs


Recording range 0 – 1.0
Wave length 275 – 255 nm
Slit width 2 nm
Scan speed Slow
Ensure that nothing is placed in sample compartment to obstruct the
optical path way.

Put hexane in both cubtte and perform base line correction. Place .02
v/v sample of toluene in hexane in the sample holder and measure the
spectrum with hexane reference.

Specification

The ratio of absorbance about max 269 nm – min 266 nm. Should be at
least 1.2

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