Potassium chloride filter for checking stray light (200 nm)

The potassium chloride liquid filter (UV1) consists of 12g/l potassium chloride dissolved in pure water. This filter is suited to check the stray light of a spectrometer in the spectral range between 190 nm and 205 nm, its cut-off is at about 200 nm.

Two regulations - two measuring methods
Currently there are different methods used in the European Pharmacopoeia (EP) and in the United States Pharmacopeia (USP) to determine the stray light.



Checking stray light according to EP (European Pharmacopoeia):

Measurement of potassium chloride (UV1) against reference filter pure water (UV12)


Typical spectrum of the stray light filters in accordance to Ph. Eur.


Checking according to USP<857> (United States Pharmacopeia)

Measurement of potassium chloride (UV1, PL 10mm) against reference filter potassium chloride (UV1H, PL 5mm)

Typical spectrum of stray light filters according to USP <857>


Note on measuring method according to USP

Experiences from daily practice show that the values determined in this stray light measuring method are instrument-dependent. This means the wavelength of the peak varies depending on the spectrophotometer performance. It is important for the user to know that the measured maximum absorption in the checked range is decisive for this checking method and that it should be higher than 0.7 Abs.

ARTICLE-NO. EP-Set: 667100 (UV1/UV12)      Request this article
USP-Set: 667100H (UV1/UV1H)    
APPLICATION Checking stray light in the spectral range of 190 - 205 nm according to EP and USP
CONTENT Potassium chloride 12 g/l in pure water
STANDARD CERTIFICATION Cut-off wavelength: 200 nm
Slit width: 2 nm; with DAkkS calibration certificate
POSSIBLE CERTIFICATION Cut-off wavelength: fix
Slit width: 2 to 5 nm


Reference Materials (Brochure & User Manual EN)


Liquid-based, optical reference material UV1 and UV1H (Safety Information EN)



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