Table IV. Recovery of Metals through the TnOA Extraction-Spectrographic Procedure
Recov- Rel. Added, Found,& ery, std. dev., Metal Ta Ti W
pg.
pg.
70
50
46 0 98 44
92 98 88 110
7%
f8.4 1 f4.9 iz5.7 50 Zr 1 1.1 iz9.0 Av. f 7 . 0 Average of 6 determinations.
The method was tested by spiking plutonium solutions with the metals of interest and measuring their recoveries throygh the TnOA extraction-spectrographic procedure. The data are shown in Table 1V. Eighty-eight to 100% spike recoveries were obtained. On 24 such measurements, a relative standard was estimated. deviation of +7% Fifty to 2000 p.p.m. of tantalum and tungsten and 5 to 200 p.p.m. of titanium and zirconium in 100 mg. of plutonium are conveniently determined.
LITERATURE CITED
G. R., "Wavelength Tables," pp. XTIII-XX, The Technology Press, Wiley, New York, 1939. ( 2 ) K O , R., ANAL.CHE'vf. 36, 1290 (1964). (3) "Metals Handbook," 8th ed., ToI. 1, pp. 46-7, American Society for Metals, Cleveland, Ohio, 1961. (1) Harrison,
ROYKO Hanford Laboratories General Electric Co. Richland, Wash.
Use of Porous Glass for Gas Chromatographic Separation SIR: Porous glass has recently been used as a gas-chromatographic separation medium (1, 2 ) . An attempt was made in this laboratory to extend this technique to the separation of highboiling materials. X temperature programmed Aerograph Hy-Fi 600-C, with the flame ionization detection system, was used in this study. The gas chromatograph was equipped with an Aerograph hydrogen generator. stainless steel column, 6 feet long, '/,-inch 0.d. was packed with untreated porous glass (Corning Glass Co. Code 7930), 50- to 80-mesh size. Surface characteristics of porous glass were determined using the Isorpa made by Engelhard Industries and found to be: surface area, 173.2 sq. meter per gram; pore volume, 0.109 ml. per gram; average pore size, 25.2 A. In the initial experiment, separation of lower saturated and unsaturated (C,-C,) hydrocarbons was attempted. Methane, ethane, propane, isobutane, n-butane, and unsaturated Cd hydrocarbons were separated. X mixture of normal pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, and hexadecane was then prepared and separation attempted under temperature programmed conditions. h perfect resolution of all hydrocarbons was obtained as shown in Figure 1. No tailing of peaks was observed. The highest boiling comppund of the series, hexadecane (b.p. 287.5"C.), was eluted a t a temperature of approximately 250" C. in 30 minutes. To establish an upper temperature limit for the use of this adsorbant, the following experiment was conducted. A gas chromatographic column used for the separation of hydrocarbons was placed into a muffle oven a t 850" C. for 2 hours. ;\fterwards this column was used for the separation of the same hydrocarbon mixture. Identical results were obtained in terms of retention time and peak symmetry. The experiment indicated that temperatures as A \
251 4
ANALYTICAL CHEMISTRY
high as 850" C. do not affect adsorbant characteristics of porous glass and that the column can be operated up to temperatures a t which pyrolytic decomposition of specific analyzed materials begins. An attempt to use this column for the separation of polar materials was unsuccessful because of an extremely high degree of affinity between the polar material and porous glass. Partial success has been obtained with a modified porous glass. Modification was accomplished by coating porous glass grains with 0.6 and 3.0y0 phenolformaldehyde resin. A sample of methanol which was almost completely retained on an untreated porous glass
Figure 1 .
Separation of
produced a definite peak on the polymer treated porous glass. LITERATURE CITED
(1) hlacDonel1, H. L., Soonan, J. AI., Williams, J. P., ASAL. CHmf. 35, 1253 (1963). ( 2 ) Zhdanoff, S. P., et al., Seftokhimza 3 , 418 (1963). IHOR LYSYJ P. R. XEWTOX Research Department Rocketdpne Division of Xorth American Aviation, Inc. Canoga Park, Calif. WORKsupported by the U. S. Department of Interior, Office of Saline FTater, Contract N o . 1401-0001-332.
Cg to CX saturated
hydrocarbons
Instrumenk Aeragraph HY-Fi, M a d e l 6 0 0 - C Detector: Flame ionization; H2 flow, 20 cc. p e r minute; oir flow, 2 5 0 cc. p e r minute Column: 6 feet long b y '1s-inch diameter packed with Corning porous glass No. 7930, 50- to 80-mesh size Sample: Mixture o f Cg to Cla saturated hydrocarbons; sample size, 0.5 pi. Carrier gas: Nitrogen; Inlet pressure, 35 p.r.i.g. Temperature: Programmed from 75' to 250' C. Sensitivity: 100 X 16 Recorder: Varian, 9-mv. full scale response; speed, 2.5 inches p e r minute Peaks in order of elution: n-propane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-unidecane, n-dodecane, n-tridecane, n-tetradecane, n-hexadecane
