Automatic Volume Fraction Collector. Charles Alader, Agricultural Chemistry Research, Oklahoma A. and 31. College, Stillwater, Okla., m d George &fader, Jr., Dewey, Okls. automatic fraction collector that collects a ecrtam volume irrespective of time is needed in oolumn chromatography or m y other analysis where volume fractions are used but the rate of delivery is not constant with respect to time. @ INE~FNSIVE
stopper with two heavy copper wires inserted, to which the mercury switch leads are connected. The pivot wires balance in two slots covered with sheet copper, whence connection is made to the collector mechanism. This prevents interference by connect. ing wires with the movement of the pipehwiteh and allows operation with fractions as s m d as 3 ml. The vertical movement is controlled by two horisontal pegs, one above and one below the svitrh. COLLECTOR MECHANISM
R L 2 ;&itch. The W-kil&h~resi& allows the condenser ta discharge for about 2 seconds. This discharge starts the lowspeed motor, which moves the turntable off the stop and close* the turntable switch. This switch allows the motor to cantinueoueratine until the turntable switch is w e n d . when it comes;
volt alternating current. 5006ohm. sindecantact relav made by Potter and Brumfield, Princeto“, I n d The turntable switch consists of a Spring contact switch, one contact of which is extended so that it will be opened by a turntable stou.
Figure 1. Pipet-Switch
Fiteh and Russell C?), Phillips (7), and Randall and Martin (8) used mechanical escape mechanisms; Stein and Moore ( 1 0 ) and D m o , Schall, and Whistler ( 8 ) used a photoelectric principle; Gilson ( 4 ) used an electronic capacity switch and a ratchet turntable; Grant and Stitch (5)and Harris (6) used a mercury switch operated by the differential level in the delivery siphon and a ratchet turntable; and Brimley and Snow ( 1 )used n device with an electromagnetioally tilted mercury switch which required large volume fractions far operation. These devices are limited in use hy t,heir cost or by their mechanical nature. PIPET-SWITCH
This pipeeswitch consists of a siphon pipet similar to that described by Rieman and Lindenbaum ( 9 ) with 3r mercury switch as shown in Figure 1. Such a pipet will quantitatively deliver the fraction volumes. The pivot consist, of a rubher zoon RECTlF I L R
Figure 3.
Fraction Collector
By proper adjustment of the stops, any number or shape of receiving vessel8 may be used, limited only by the area of the turntable. The mechanism ia not adversely affected if the mercury bounces upon closing of the mercury switch. LITERATURE CITED
Figure 2. A . Pipet-switch
(1) Bnnlley, R.C., and Snow, A., J. Sci. Inst?.. 26,73 (1949). ( 2 ) Durso, D. F., Schall, E. D., and Whistler, R. L., ANAL.CHEM., 23, 425 (1951). (3) Fitoh, F. T., and Russell, D. S.,Ibid., 23, 1469 (1951). (4) Gilson, A. R.,Chemisby & Idusby. 1951, 185. ( 5 ) Grant, R.A,, and Stitch, S. R., Ibid., 1951, 230. (6) Harris. J. O.,Ibid., 1951, 255. (7) Phillips, D. M. P., Natwe, 164, 545 (1949). ( 8 ) Randall, S. S., and Martin, A. J. P., B i o c h a . J . . 44,ii (1949). (9) Rieman, W., and Lindenbaurn, S., ANAL. C ~ E M .24, , 1199
Circuit Diagram B. Turntable svileh
11952).
(10) Stein, W. H., and Moore, S., J. B i d . Chem., 176, 337 (1948). 1423
