Measurement of acetone (UV19) against air (high-purity acetone is used and not dissolved in water)

Note
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 330 nm.

In USP <857> (update Dec. 2022), two possible procedures are described for checking for stray light:

Procedure A
Here the acetone filter (UV19) with a path length of 10 mm is measured against the acetone reference filter (UV19H) with a path length of 5 mm. The stray light value can now be calculated from the absorbance maximum obtained, using the following formula:
S_λ = 0.25 x 10^-2∆A
The following acceptance criteria apply:
∆A ≥ 0.7 Abs and S_λ ≤ 0.01

Procedure B
Here the acetone filter (UV19) with a path length of 10 mm is measured against air (high-purity acetone is used and not dissolved in water). The measured absorbance value at the recommended wavelength 300 nm should be ≥ 2.0 Abs.

Note
Procedure B of USP 857 corresponds to the procedure of the European Pharmacopoeia