A Control and a Precision method are used for the determinationof apparent hydrogen sulfide in amine solutions. Hydrogen sulfideis determined by oxidation with standard iodine solution in an acidmedium. Thiosulfate, if present, is also titrated and is includedas apparent H2S in the calculation. Thiosulfate may be determinedby using UOP Method 818, and the value thus obtained subtractedfrom the apparent H2S concentration. The lower limit of detectionis approximately 25 grains/gallon.