Commission Regulation (EEC) No 000/90 of 17 September 1990 determining Community methods for the analysis of wines (repealed) (c. 2676)

ANNEX U.K.

7. GLUCOSE AND FRUCTOSE U.K.

4. REAGENTS U.K.

4.1. Solution 1: buffer solution (0,3 M triethanolamine, pH 7,6, 4 × 10⁻³ M in Mg²⁺): dissolve 11,2 g triethanolamine hydrochloride ((C₂H₅)₃N · HCl) and 0,2 g MgSO₄ · 7H₂O in 150 ml of doubly distilled water, add about 4 ml of 5 M sodium hydroxide (NaOH) solution to obtain a pH value of 7,6 and make up to 200 ml. U.K.

This buffer solution may be kept for four weeks at + 4 °C.

4.2. Solution 2: nicotinamide adenine dinucleotide phosphate solution (about 11,5 × 10⁻³ M): dissolve 50 mg disodium nicotinamide adenine dinucleotide phosphate in 5 ml of doubly distilled water. U.K.

This solution may be kept for four weeks at +4 °C.

4.3. Solution 3: adenosine 5′-triphosphate solution (about 81 × 10⁻³ M): dissolve 250 mg disodium adenosine 5′-triphosphate and 250 mg sodium hydrogencarbonate (NaHCO₃) in 5 ml of doubly distilled water. U.K.

This solution may be kept for four weeks at +4 °C.

4.4. Solution 4: hexokinase/glucose 6-phosphate dehydrogenase: mix 0,5 ml hexokinase (2 mg of protein/ml or 280 U/ml) with 0,5 ml glucose 6-phosphate dehydrogenase (1 mg of protein/ml). U.K.

This mixture may be kept for a year at about +4 °C.

4.5. Solution 5: phosphoglucose isomerase (2 mg of protein/ml or 700 U/ml). The suspension is used undiluted. U.K.

This may be kept for a year at about +4 °C.

Note: U.K.

All solutions used above are available commercially. U.K.