Thermometer kit(3xrad122 w/therm) x 3

The H2S calibration standard contains a methylene blue concentrate that, once diluted 1:50 (v/v) with water, provides the same absorbance value of hydrogen sulfide at 665 nm at a concentration of 1.145 μg/mL sulfide ions. This concentration value is the highest absorbance value within the linear range of the spectrophotometer and can be used as a stock solution to prepare standards for the calibration curve. The concentrate is suitable for preparing up to 50 calibration curve and is stable for at least 1 year.