Standard solutions are particularly used for calibrating the absorbance of spectrophotometers.

• Absorbance measured in a 10 mm cells at 20 ±1 °C against sulphuric acid reference solution:
• Absorbance 235 nm: 0,601 to 0,641 (50 mg/ml), 1,222 to 1,262 (100 mg/ml)
• Absorbance 257 nm: 0,702 to 0,742 (50 mg/ml), 1,424 to 1,464 (100 mg/ml)
• Absorbance 313 nm: 0,222 to 0,262 (50 mg/ml), 0,464 to 0,504 (100 mg/ml)
• Absorbance 350 nm: 0,516 to 0,556 (50 mg/ml), 1,051 to 1,091 (100 mg/ml)