Calibration of UV by Control of Absorbance with Demo image

Calibration of UV-VIS spectrophotometer by Control  of  Absorbance

Control  of  Absorbance



Potassium Dichromate Solution:-

Weigh & transfer a quantity about 30 mg of previously dried Potassium Dichromate ( NIST ) at least 4 hour at 130 C ) to 500 ml volumetric flask. Dissolve & dilute in sufficient 0.005M H2SO4 (136 μL) to produce 500 ml. 


Blank 0.005M H2SO4 solution :-

Add 136 μL of concentrated sulfuric acid ( 98% H2SO4   specific gravity g 1.84) into a 500 ml volumetric flask containing 250 ml of purified water. Mix, cool and dilute to volume.


Go to Photometric mode

  • press Ctr+M
  • Add wavelength 235,257,313 & 350 nm {Select RAW DATA}
  • Make sure that Reference and sample cell holder is empty and press button for baseline correction(230 to 350 nm). 
  • Then keep the Potassium dichromate Solution in the sample cell holder & using 0.005 M H2SO4 solution as a blank 
  • Close the cell compartment 
  • Click Start
  • Calculate value of A (1% 1 cm) for each wavelength and record it.
  • Specific Absorbance = Observed Absorbance/ 0.006

Acceptance criteria:-


Wavelengths (nm)Limit
235122.9 - 126.2
257142.8 - 145.7
31347.0 - 50.3
350105.6 - 108.2


Control  of  Absorbance demo image
CONTROL OF ABSORBANCE (UV calibration) K2Cr2O7


If calibration is satisfactory then affix the status label on it with the next due calibration date.

Frequency

Once in a 3 month

REFERENCE

Indian Pharmacopoeia/ British Pharmacopoeia/ US Pharmacopoeia / TGA Appendix D SOP : Operation Of Spectro Photometer


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