ANALYTICAL CHEMISTRY
222 vents, eeperially nitromethane, care must be taken t(J avoid Itq loss RESULTS WITH SAWPLES OF K N O W S METHOXYCHLOR COYTENT
Varying knon-n amounts of methoxychlor were added to 10gram samples of beef f a t and butterfat and to 100-gram samples of milk. The samples were extracted, the insecticide was separated from the fat, and the methoxychlor was determined by the described method Recoveries obtained are given in Table I ACKhOWLEDGVEXT
‘Ihe authuis niPh to thank T. I€. Hairi., Production and Marketing i\dministration, G. S. Department of Agriculture, fox lielpful suggestions on t h e separation of methoxychlor from fat.
LITERATI.TRI.: CITED ‘1 1 Bisho~)p,F. C..
and Knipling. E. F..I n d . Eng. Chem., 40, 713-16
(1948). 12) Carter. R. H.. ISD.EX. C H n i . . A X A I . .ED.,19.. 54 (1947). . . ‘ 8 ) Fairing. J. D.. and Warrington, H. P.. J r . . .Idi,uncps in Chem. ser., s o . 1,260 (1950). (4) Huller, Bartlctt, Drake. Sewman, ct n i . . J . -4m.Chem. Soc., 67, 1591 (1945).
(5) Harris, T. H., private communication. F..U. S. L)ept..Agr., Bur. Entomol. and Plant Quarantinc. E-762 (2nd revision, June 1951). ( 7 ) Prickett, C. S.,I i u n z c , E’. M.,and Laug. E. P.,J . Assoc. O ~ C .
(6) Knipling, E.
(S’
A g r . f ‘ h , ~ n i i d s . 33, 580 (1OL5Oi. Scherhter. 11. 8.. Pogorelskin. .\I.A . and Hallcr, H. L...
Esr,.
C k n f . , .\s.\L.
ISD.
Em, 19, 5 1 (1947).
RECEIVED.Jnnri:Iv>. 8. 1931.
Boric Sinter Method for Determination of Sodium Oxide in Alumina 4 , K. 4JIC‘IIIBtLD A-D \1. E. JIcLEOI) C o . of Canada, L t d . , trrida,Qweber. Canada
t/rtrtiinuttt
“E
solution of refractom suhstances such as alumina for determination of sodium oxide content by the classical J. 1,aivrence Sniith method (3, 5) is a time-consuming procedure t h a t docs not lend itself well to the routine chemical laboratory. .Jackson (4) recentlj- published a procedure embod! ing heating the alumina samples with hdrochloric acid in scaled tubes at 200” C. This procedure, although an improvement on the classical method, is not particularly rapid, and lequires the fabrication of glass tubes able to withstand considerable pressure. .Ittempt@ by the authors to develop an acid lmching procedure at atmospheric pressure on finely ground alumina did not prove successful; resultant soda values yere invariably Ion- cven with very finely ground samples and prolonged digestion periods However, they have fount1 trhata boric acid or boric o\ride sinter of alumina provides a rapid iiicthod for hinging the soda in this material into solutiori, the precision of the soda values ohtained being :I$ good as i n - thc 1,nwrence Sniith fusion. I’RO(.EDURE
.I finely giouiid simple of witable size (0.5 to 1 gram J is mixed Tell with the appropriate amount of reagent grade boric oxide 01 boric acid. For a 0.5-gram sample of alumina, 0.85 gram of BIOj is recommentled. 1 gram or 1.5 grams of HYBOn per 0.5 gram of alumina also piovide a satisfactory mi\ture. The mixture is placed in a platinum crucible, covered, and heated over a low flame for approximately 5 minutes. T h e temperature i- then increased to full burner flame, and the sinter continued for another five minutes. Too high a temperature a t the outset of the sinter cnn cause mechanical loss of sample. After the crucible has been removed from the flame and cooled, the sintered mass is knocked into a 250-nil. lxaker, 10 to 15 ml. of mater are added to thc crucible and heated to boiling, 2nd the .-
‘Table I. Ralnl,li, SO.
1 3
,! 6
b
0 10 11 12
13 I4 13 I li 17
I’arallel Determinations of Soda Content of .Alumin a Samples ~ _ _ _ ___~
U320. c,
~ ~~~
.Siiiith
fiiaion
i1.88,0.83,0 8:
0.79 l1.67.0.66 n. 63.0. 0.51.0.54 0 51,O. J-L 0.81) 0.82 0.77 0.71 0.67 0.W 0.5; 0.53 0.51 0.46 0 42
~
r b i r Einter
0.82,O.83 0.80,O. 80 0 . 6 4 , O . 66 0 60,O. BR
n.~z.o.si
0 . 5 4 , 0 .53 0.92 0.82 0.74 0.68 0.66 0.64 0.56
0.53 0.52 0.46
0.41
crucible and cover are policed into the heaker. . 4 few drops of concentrated hydrochloric acid are then added and the mixture i. boiled for about 3 minutes to break up the sinter. The solution ib filtered on a S. & S. 589 Blue Rand paper, and the paper is washer1 wrll with hot ivater. Soda may he determined on tlic filtrate using any standartl procedure; the authors’ laboratory utilizes thc Perkin-Elmer flame photometer, with boron added to the standards, but precipitation with zinc uranyl acetate ( 1 ) is also satisfactory, thr determination being finished by direct weighing, or by titration of a reduced sulfuric acid solution of the triple salt with nmmoniuni hexanitrate cerate (or sulfatoceric acid) using ferrous o-phennntlirolinr complex as an indicator. 11Ii(~ zinc urmyl acrtate prwipitiit ion is used, some lroric aciti 11iay crystallize out during evaporation of the filtrate to small volume prior to prccipitntion. However, the lioric acid redi,ssolves readily on addition of .sufficient zinc uranyi acetate reagent 3olution. The authorp’ 1)ractice calls for 100 ml. of zinc uranyl acetate solution for a 5-nil. volume of evaporated filtrate; this amount is actually somewhat in excess of that, required, but a very satisfactory procedure ( 2 ) for recovery of uranium values i p available. T h e alcohol washing of the precipit,ate provides a further.safcty factor for removal of any precipitated boric acid i f less than 100 nil. of zinc uranyl acetat,c are used. If the deterinination is finished volumetrically, any precipitated boric acid ill bc redissolved in the volume used for titration. RESULTS
Table I shows t,he resulte of a series of parallel determinations of soda content on seventeen alumina samples by the boric sinter and by J. Lawrence Smith fusion. The soda values shown were obtained by weighing the precipitated (UOJZ. %nKa(C?H30~)s.611g0, a blank being carried through the prowdure. I)ISCUSSIOT
1Thile they have hati only limited eq)erirnrc in application of t h c Imic sinter procedure to materia!s other than alumina, the authors feel that i t could he successfu3y applied t o a variety of other materials where t h e Sniith fusion :it,tnck is ordinarily
cniploped. LITERATURE CITEI)
(1) Barber, H. H.. and Iiolthoff, I. 51.. J . A n t . (’hem. SOC..50, 1625 (1928). (2) Clark, F., A t i a l ~ d74, , 411 (1949). 13) Hillebrand, W. F..V. P Ceol. Survey. Bull 422, 171 (1910) (4) Jackson, R . , Analyst, 75, 414 (1950). ( 5 ) Smith, J. L., A m . .J Sci., (3) 1, 269 (1571)
