calibrator film, inserted additionally in the sample beam, was obtained while matched thicknesses of filter were present in the trvo heani. I t is quite obvious that the instrument rrniains “live” and faithfully traces the 840 em.-’ and 1072 ci11.-~ bands of re 3A is an illustration of the qiectrum obtained from apl)roximately 3 pl. of ail actual chc>mical sample flcyosited on a meinbrarir filt,er, and vompensated with a matching thicklies ( i f filter in the reference lieam. The +ample ih di-n-octyll)ht~halatr. Except ror the anomalous region near 1660 (.mi.-1; the spectrum compares farorabljivith that, obtained by scanning the +xmple undiluted in a thin, sealed i)ot:rsi.ium bromide cell (Figure 3 B ) . The membrane filter has several liinit,ations, ho\vever. Care mu-t be rserciieti in the choice of solvents to be used with this polymeric material. While most hydrocarbons. chlorinated hydrocarbons mineral acids, bases, id higher alcohols do not affect thr
filter, the lower alcohols, hetone>, esters, and ether alcohols dissolve the polymer
(4)’
Second, these filters, especially the thin TH type, normally pick up a considerable electrostatic charge and are difficult to handle and n-eigh. This charge may be partially dissipated with an alpha ionizing Source +uch as a polonium d r i p (available from Suclear Products Co., El Monte, Calif.). ,\pplication of the infrared differential technique employing membrane filters ha. not been thoroughly investigated. \Ye used the method to examine contaminants filtered from hydraulic fluid, and condenyate. from tobacco -moke. Potential applications -et’m mort’ di1 e r v than this. The ?\Illlipore membrane filter has already becn . h o w to be a rather eficient traj) for ga3 cliromatographic fraction\ ( 2 ) and it may be po-ible to examine the trapped GC effluent, h] infrared in the manner d e w 4 x d . The twhnique ma to air ~iollutioninve
amiliation of materials coliected from “clean” room atmospheres. There is also some indication that the Xllipore filter i i a useful medium for “paper” chromatography and electrophoresis ( I ) , in which case infrared identification of the spots or s t r e a h obtained seems promising. This probably will require xi-ork with microapparatus. LITERATURE CITED
J . L., JIillipore Filter Corp., Bedford, Mass.! private commiiniratiori,
( 1 ) Divyer,
1!16?.
( 2 ) Hajra, -4.K.) Radin, S.S..J . Lipid Kes. 2, 131 (1961). ( 3 ) Matthem, I:amplr drops to the bottom of tlw flask before 1)urning is coniplt.te. -1portion of the sample or a pieve of lo\~-a*h filter l i a p r is ~isodfor the ignition wick as >lion-n in Figure 1. To incrrasc. the : i b ~ o r ~ ) t i oofn radiant ~ n e r g y the < tip of t h r ivkk is t h c k e n e d \\-ith k a d pencil mplf 1ioldc.r is hooked ovcr the, Iiositioning roil. lowered into the fla-k, : t i i d the s;:tmple hcight adjusted that the wick is : n line with and (lirc~-tly :iliovr the projector bulb. . k i d , :tlkali, or water is a d d 4 to the Iiottoin of tlie flask tci dissolw the a521 :iItw c.oml)u*tion. T l i t ~ lialloon and :itlal)tc~are rcmoved, and the flask is fliidictl ant1 fillrtl with oxygen pas.
After t h e balloon is replaced and a safety shield is in position, the lamp is turned on until combustion is started. soon as combustion is complete, t h e Iilat,inuni wire is dropped t o the bottom of the flask in contact with the ash solvent. The flask, which may be cooled rapidly by spraying the outer Furface with Ivater. i i held iintil any aerosol disperses; then the a$h solution and the water used to rinse the balloon and tlie combustion flask are aspirated into a flask for analysis.
Iron in tlip form of ferric chloritic solution was added to n-oodpulp and Whatman S o . 10 filter paper. ‘Thcl ash ij-a> d i w ~ l v t din 20 nil. of 1:1 HCI. ant1 t h r iron tletc.rniiiied with 4 . i tliphen~-l-l,l0-phcnanthroline(batho~iheiiaiithrolinr.) using a modification of t h r I)roccdure of Gahler, Harnner. and ShiilxJrt ( 2 ) .
RESULTS
The apparatu. ha> been u w l for the analy4s of iron, cwpper, and chloride in woodpulp. Some of the iron rrcovery tlata are presented in Table I.
Rapid Scanning of Radioactive Thin layer Chromatograms Joseph Rosenberg anti Michael Bolgar, Organic Chemistry Department, Tracerlab Division, laboratory for Electroiiics, Inc., Waltham, Mass.
VOL. 35, NO. 10, SEPTEMBER 1963
1559
