Provided is a use of a deep eutectic solvent to inhibit the degradation of a biomolecule, wherein the biomolecule is a protein. The deep eutectic solvent comprises a first component and a second component. The first component is a compound of Formula I:wherein: R6 is H or OH R7 is selected from H, CH3, Cl, Br, a carbonyl oxygen, andZ is selected from -CH2-, O and S and R8 is R11 or OH. The second component comprises a compound of Formula II or a salt thereof:wherein: A is selected from O, S, and NH R1 is selected from R9 and -C(R3)(R4)(R5) R2 is selected from H and linear alkyl group having 1 to 3 carbon atoms R3 is an optionally substituted 5- or 6-membered aliphatic or aromatic ring, wherein the substituent is R10 R4 and R5 are F. R9 is a mono-, di- or trifluoromethyl group or a mono-, di- or tri-fluoroethyl group and R10 and R11 are each independently selected from alkyl groups having one to three carbon atoms, monochloroalkyl groups having one to three carbon atoms, and mono-, di- or tri-fluoroalkyl groups having one to three carbon atoms.
