A fellow translator is having trouble translating (into Russian) the mysterious D.H. abbreviation in the following passage:
Slight variations of the ratio of the mobile phase constituents or adjustments of the mobile phase flow-rate can be made occasionally, in order to provide a suitable elution times for Methyl p-hydroxybenzoate and D.H., and to meet the requirements of the system suitability tests.
If by some chance it's a widely known compound, or at least there are several chemicals that could be abbreviated thus, I'd be grateful for answers. A crapshoot, I know, but I became curious.
It could be some rare chemical; in that case it would be futile to try figuring it out.