Peak separation you've never seen before.
Letters
Typographical Error Sir: A reader has called my attention to an unfortunate typographical error in my April 1979 ANALYTICAL A P P R O A C H article on t h e J F K Assassina
INSTEAD OF THIS
THIS
New from this X-ray fluorescence analyzer.
A new and unique pulse processor gives our SPECTRACE'" analyzer guaranteed resolution of 150 eV —the best ever achieved in an energy-dispersive X-ray fluorescence analyzer. This resolu tion, coupled with peak shifts no greater than 3 eV at maximum count rate, lets you detect light elements more reliably and quantify them more accurately. The spectrum at left above shows an actual peak separation using the new pulse processor. That at right, with overlapping peaks, was made using a conventional processor in the same analyzer. SPECTRACE 440 can make auto matic unattended analyses of up to
40 samples —solids, liquids, powders or deposits on filter paper. Makes qualitative and quantitative analyses of all elements from Na to Pu. Han dles samples from 1 mm in diameter to a foot high. Has superb sensitivity, repeatability and long-term stability. Our applications laboratory and engineering group will work with you to help solve your analytical problem. That way you know you'll get the results you want after your SPECTRACE is delivered. Over 50 SPECTRACE analyzers are now in use. And we'll give you the name of every single user — because we know every one will give you a favorable report. One thing they'll report is the service they get: personal instruction, an applications school, software school —and follow-up visits just to make sure you're getting the most out of your SPECTRACE. Send for our highly informative brochure now. Contact United Scientific Corporation, Analytical Instrument Division, Dept. C 1400 Stierlin Road, P.O. Box 1389, Mt. View, California 94042. Phone (415) 969-9400.
USUNITED
m SCIENTIFIC
ANALYTICAL INSTRUMENTS DIVISION CIRCLE 214 ON READER SERVICE CARD
1284 A · ANALYTICAL CHEMISTRY, VOL. 5 1 , NO. 13, NOVEMBER 1979
tion (pages 484 A-493 A). The error occurs in the second column of page 492 A, in lines 8-10. In my typed man uscript, the wording is correct, b u t a portion of the parenthetical expres sion was lost in the typesetting, lead ing to an erroneous statement. Whereas the published article states " . . .(Q4,5 being fragments recovered from two different areas in the Dallas l i m o u s i n e ) . . . , " it should read: ". . .(Q4,5 being fragments recovered from President Kennedy's brain, and Q2 and Q14 being fragments recovered from two different areas in the Dallas limousine). . . ." Vincent P. Guinn Department of Chemistry University of California Irvine, Calif. 92717
Any Volunteers for Niobium Analysis? Sir: The Canadian Certified Refer ence Materials Project (CCRMP) is currently certifying a pyrochlore ore from Oka, Quebec, encoded ΟΚΑ-1, at ~0.5% Nb. The usual practice of the C C R M P is to request a minimum of 20 laboratories to participate on a vol untary basis in a round-robin certifi cation program for the chosen ele m e n t s ) in the candidate material. T h e lack of laboratories experienced in niobium analysis, however, requires a significant departure from this prac tice, and it is planned to certify ΟΚΑ-1 for niobium with the partici pation of considerably fewer but expe rienced laboratories. Anyone interested in participating in this round-robin certification should contact the writer for further information. Henry F. Steger Coordinator, C C R M P 555 Booth St. Ottawa, Ont. K l A 0G1 Canada
