The acetone liquid filter (UV19) consists of pure acetone. This filter is suited to check the stray light of a spectrophotometer in the spectral range between 250 nm and 324 nm, its cut-off is at about 322 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.
Measurement of acetone (UV19) against air (high-purity acetone is used and not dissolved in water)
Currently, the use of the acetone stray light filter is required only in the United States Pharmacopeia (USP) for the determination of the stray light in the spectral range from 250 nm to 324 nm.
Typical spectrum of the stray light filters in accordance to Ph. Eur.
Measurement of acetone (UV19, PL 10mm) against reference filter acetone (UV19H, PL 5mm)
Typical spectrum of stray light filters according to USP <857>
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 Art-No.: 667019 (UV19) Request this article |
USP-Set: 667119H (UV19/UV19H)
|APPLICATION||Checking stray light in the spectral range of 250 - 324 nm according to EP and USP|
|CONTENT||high purity Acetone|
|STANDARD CERTIFICATION||Cut-off wavelength: 322 nm |
Slit width: 2 nm; with DAkkS calibration certificate
|POSSIBLE CERTIFICATION||Cut-off wavelength: fix |
Slit width: 2 to 5 nm