Saturday, October 18, 2008


1.0 PROCEDURE : For control of absorbances.
1.1 Preparation of Potassium dichromate solution.
1.2 Dry Potassium dichromate at 130°C for 2 hours. Weigh accurately about 60mg of potassium dichromate into 1000ml volumetric flask. Add 0.005 M sulfuric acid to dissolve and dilute with same solvent.
1.3 Calibration :
Using the Wave lengths.
235 nm
313 nm
257 nm
350 nm
Find out the absorbance of a A(1% cm).
Calculate the A(1% cm) value as per the formula for each wavelengths.
Check the value for each wavelengths with tolerances given for all four wavelengths
Tolerances (ie)

2.0 PROCEDURE : For Limit of stray light
2.1 Preparation of 1.2% w/v of Potassium chloride solution.
2.2 Dry Potassium chloride at 105C for 2 hours. Weigh accurately about 1.2 g of potassium chloride into 100 ml volumetric flask. Add water to dissolve and dilute with the same solvent.
2.3 Calibration :
Stray light detected at a wavelength at 200 nm
Find out the absorbance at 200 nm with tolerance should be greater than 2.0
3.0 Procedure for Resolution power
3.1 Preparation of 0.02% v/v solutions of toluene in hexane
3.2 Pipette 2 mL of Toluene AR grade to 100 ml with Hexane AR grade and mix.
3.3 Calibration :
Using the wavelengths
269 nm
266 nm
Find out the ratio of the absorbance at the maximum at about 269 nm to that at the minimum at about 266 nm with tolerance should be not less than 1.5.
4.0 Preparation of Reagents (0.005 M sulphuric acid)
i) Dilute 3 ml of concentrated Sulfuric acid to 100 mL with water and mix.
ii) To 10 mL solution into 1000 mL wirh water and mix.
5.1 F:Sxxx/ UCR/A - UV-Visible Spectrophotometer Calibration record.

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