NOVELTY - A 4-nitrophenyl hydrazine carboxy-reduced benzaldehyde polyethylene glycol 400 monolaurate surfactant-containing electrolyte solution comprises 0.7 mmol 4-nitrophenyl hydrazine carboxy-reduced benzaldehyde polyethylene glycol 400 monolaurate surfactant (I) and 6 mol/L saturated zinc oxide-containing potassium hydroxide solution.    USE - Electrolyte solution (claimed).    DETAILED DESCRIPTION - A 4-nitrophenyl hydrazine carboxy-reduced benzaldehyde polyethylene glycol 400 monolaurate surfactant-containing electrolyte solution comprises 0.7 mmol 4-nitrophenyl hydrazine carboxy-reduced benzaldehyde polyethylene glycol 400 monolaurate surfactant of formula (I) and 6 mol/L saturated zinc oxide-containing potassium hydroxide solution. An INDEPENDENT CLAIM is included for preparation of 4-nitrophenyl hydrazine carboxy-reduced benzaldehyde polyethylene glycol 400 monolaurate surfactant-containing electrolyte solution, which involves adding 3 g carboxybenzaldehyde, 0.153 g 4-dimethylaminopyridine and 2.58 g dicyclohexyl carbodiimide to three-necked flask, placing the three-necked flask in a water bath, dissolving 2.58 g polyethylene glycol 400 monolaurate in 10 mL dichloromethane, adding resultant solution to dropped three-necked flask, reacting resultant mixture at room temperature for 24 hours, placing the reaction mixture in a refrigerator freezer for 15 minutes, filtering precipitated dicyclohexylurea, rotary-evaporating the filtrate, obtaining white viscous oily solid of carboxybenzaldehyde polyethylene glycol 400 monolaurate, dissolving 2.912 g carboxybenzaldehyde polyethylene glycol 400 monolaurate in 20 mL ethanol, obtaining carboxybenzaldehyde polyethylene glycol 400 monolaurate ethanol solution, dissolving 1 g 4-nitrophenyl hydrazine in 30 mL ethanol in three-necked flask, placing the three-necked flask in a glycerin bath, heating to 70 degrees C, adding carboxybenzaldehyde polyethylene glycol 400 monolaurate ethanol solution to the three-necked flask, reacting, rotary-evaporating the reaction liquid, obtaining yellow viscous oily solid of 4-nitrophenyl hydrazine carboxy-reduced benzaldehyde polyethylene glycol 400 laurate surfactant, dissolving surfactant in saturated zinc oxide-containing potassium hydroxide solution, and mixing.