Organic Qualitative Analysis: The Oxygen Flask Method as an Alternative to Sodium Fusion Qualitative analysis in organic chemistry laboratories has traditionally used Lassaigne's sodium fusion method for the determination of the elements present in a substance. As noted in a recent article in this Journal.' this procedure is
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methad, descrihcd hy Roulton.i' Over the past four years, approximately 200 of our undergraduates have each used the oxygen flask method a number of times, and we are rrmvinced that this method is bath safe and reliable. Moreover, the oxygen flask method is very easy t o use even by inexperienced undergraduates (and is more spectacular than the sodium Fusion method which gives it eonsiderahle student appeal). T h e cost of the equipment required is minimal. T h e historical hackground to and development of the oxygen flask method has been ~ u m m a r i e e dWe . ~ have modified the equipment dcscrihed by 13aultan hy adding a Runsen valve t o the side arm of the Buchner flask and by using furnace wire in place ofthe stainless steel wire. We have also changed the recommended test for nitrogen. A drop of the test solution is acidifid wilh dilute hydrrrhlrrir acid on s white porcelain plate. A drop of sulfanilie acid solution is then added, f~llawed Iw a drcw c,l'rrsc,n.ind s d t t t i m . A vellow coloration indicates the nresence of nitrite. '1'111- 41m 11.11~ i. t..,nct;~ll\ r , u ~ f ~ ~ Ir ~v IeA I InI (i plm t i l t.?r wc- j r r an.lrr. lar%cl>tgn..rrcl i t t r wtchpri .qanu rhrwi.~r\.I t , i t c 11 1 ~ t1 h ct\\..tn l1t.k inptht rl .mrl nwa! Iron? the ~nl.,nl.~ . u , ~ r (I.u wdiltln lu.it I I C ) T O L ~ ~ . I ~ C \Ve .arc. I, .I>IIV I 1 v s l e A ~ V !nt C 1ntew.14 w t h thv full de1e.l. uitlw p r ~ d u r t u-td ( $ 1 < u rl , h , r ~ t ~ ~ & ~
' Vinson, .I. A. and Cmhnwiki, W. T., d. CHEM. EDUC., 54,187 (1977). ?
Roulton, C. H., Kdur.. i n ('Iwm., LO, XI1 (1973).
Griffith University Nathan, R ~ i s h a n e Queensland, J I I I. Australia
226 1 Journal of Chemical Education
R. D. G u t h r i o Ian D. J e n k i n s
