Colorimetric field method using 1,5-diphenylcarbazide

Note 1: This method updates and replaces MDHS 52/2.1
The principal changes which have been made are (i) to recommend an additional filter suitable for sample collection, (ii) to incorporate information on the test procedure for monitoring emissions from electrolytic chromium processes,
that was previously given in Environmental Hygiene Series Guidance Note EH 6,2 (iii) to reduce the minimum sampling time from 1 hour to 15 minutes, except for measurements made with a comparator, and (iv) to withdraw the requirement to apply a factor to correct results for incomplete recovery of hexavalent chromium from the filter, which recent studies have shown to be unwarranted.