Sodium Iodide for checking stray light (259 nm)

The sodium Iodide liquid filter (UV10) consists of 10 g/l sodium Iodide in pure water. This filter is suited to check the stray light of a spectrometer in the spectral range between 210 nm and 259 nm, its cut off is at about 259 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 sodium iodide (UV10) 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 sodium iodide (UV10, PL 10mm) against reference filter sodium iodide (UV10H, 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: 667101 (UV10/UV12)      Request this article
USP-Set: 667101H (UV10/UV10H)    
APPLICATION Checking stray light in the spectral range of 210 - 259 nm according to EP and USP
CONTENT Sodium Iodide 10 g/l in pure water
STANDARD CERTIFICATION Cut-off wavelength: 259 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 UV10 and UV10H (Safety Information EN)



Hellma USA Inc.
80 Skyline Drive
11803 Plainview, NY
United States

Phone: +1 5169 3908 88


Note: Your data will of course be treated confidentially and will not be shared with third parties. You can revoke your consent at any time by clicking on the end of each e-mail.
Required Field