According to a laboratory procedure hydroxylamine-O-sulfonic acid can be prepared by treating hydroxylamine sulfate with fuming sulfuric acid (oleum). The industrial process is similar.
:(NHOH)SO + 2SO → 2HNOSOH + HSO
The sulfonation of hydroxylamine can also be effected with chlorosulfonic acid by a method first published in 1925 and refined for Organic Syntheses.
The hydroxylamine-O-sulfonic acid, which should be stored at 0 °C to prevent decomposition, can be checked by iodometric titration.