How can USEPA Method 11 be modified to enhance the sensitivity of detection?
AMSAAP nominates a variety of methods for sampling and analysis of hydrogen sulfide in stack emissions. The methods vary in a number of ways, including sensitivity of detection. In particular, USEPA Method 11 is considered a cost-effective method, but one disadvantage is that the sensitivity may not be adequate to demonstrate regulatory compliance. However, there is scope within the method to improve the sensitivity. The nominal sampling time required in the method is at least 10 minutes. This sampling time can be legitimately increased to allow capture of hydrogen sulfide from an increased gas stream volume, thus having the effect of reducing the low limit of detection. However, care needs to be taken to ensure that the capture solutions are not saturated during the increased sampling time. This modification is considered to be within the scope of the method without needing the approval of the Chief Scientist to use this as an alternative method.
