BURRELL
"cjiw
NEW-highly
(2frte////'i/i-
c ~>vet///(·//fï&
sensitive
IONIZATION DETECTOR for gas
The purification steps constitute the independent variable which changes by discrete, unit intervals. Therefore, a Cartesian abscissa is appropriate, and the points m a y be connected by straight-line segments. On the inverted logarithmic scale, the origin might be zero, the beginning of the second cycle 90, the third 99, the fourth 99.9, etc. T h e unit interval in the first cycle would then be 10, in the second 1, in the third 0.1 ; t h a t is, unit intervals in eacli cycle are one tenth those of the preceding one. I n this example, four cycles would be needed to cover the range 0—99.99. Because we started with a product of 90 per cent purity, however, Ave m a y suppress the null point and start with the second cycle. With this empirical curvestraightening we have accomplished two things: N o t only does the new curve show t h a t purity has been increased with each step—a fact not obvious on the conventional curve beyond the third step—but it permits estimates of values to additional significant figures at and above the third step. These advantages are, of course, the same as those gained for low values on the true logarithmic graph. Additional details appear in an article b y Mr. Cohn " E d i t i n g G r a p h s for Publication" (American Documentation, Vol. 6, No. 2, April 1955, pages 77 to 86).
chromatography
permits large or small samples —excellent for trace analysis
absolutely non-radioactive —no hazardous materials are used
precise operator control —of ionization energy
Answering the need for better detection in chromatographic analysis, Burrell has d e v e l o p e d a c o m p l e t e l y safe and versatile ionization detector. E l e c t r o n s for i o n i z a t i o n are supplied b y e m i s s i o n , providing e x t r e m e l y h i g h sensitivity a n d fast linear r e s p o n s e . Large o r small s a m p l e s , v a r i o u s carrier g a s e s and c a p i l l a r y or p a c k e d c o l u m n s can be u s e d . C h a n g e s in flow or t e m p e r a t u r e h a v e n o a d v e r s e effects.
The Burrell Ionization Detector is available as an accessory for the Burrell Kromo-Tog, Models K-l and K.-2, or as a separate unit for other applications. Request data.
BURRELL
CORPORATION
2223 Fifth Avenue, Pittsburgh 19, Pa.
Scientific Instruments and Laboratory
Supplies
Circle No. 31 on Readers' Service Card
VOl.
32, HO. 4, APRIL 1960
·
77 A
