which was not sparged and the other of which was nitrogen sparged for 1 u00bc hours the sample preparation parameters are given in the following table after preparation and sparging the samples were placed in screw cap test tubes the caps were wrapped with electrical tape to prevent vapor loss the samples first were tested for complete solubility at room temperature the surviving samples were tested at lower and lower temperatures to determine the u201c winners u201d u2014 the samples with no precipitate at u2212 30 u00b0 f the results are given in the following table in which unsparged samples are designated with a prime 1 zero time at room temperature means crystallization occurred in samples c d e and f during the sparging operation note however that the samples were sparged for 1 1 4 hours instead of the more appropriate u00bd u00be hour as a result more water and possibly h 2 s was lost than necessary the foregoing results demonstrate that the more mea used the more stable the solution however counterbalancing this enhanced stability with more mea is the fact that less polysulfide is delivered per unit volume of solution for commercialization purposes one would have to balance the cyanide scavenging ability vs product stability tests were performed to determine cold stability using 10 wt 15 wt and 20 wt mea in kerley 39 s u201c ammonium polysulfide kc 20 40 u201d u201c aps u201d a commercial aqueous solution of ammonium polysulfide available from tessenderlo kerley each sample was prepared by adding.