HELLMA . . . tomorrow's designs today/
Briefs Peak Resolution by Semiderivative Voltammetry
1497
Overlapped voltammetric peaks are separated as semiderivatives. Synthetic data are totally resolved with peak separations as small as 25 mV, while real systems are deconvoluted with separations as small as 40 mV. Jeffrey J. Toman and Steven D. Brown*, Department of Chemistry, University of California, Berkeley, Calif. 94720, and Materials and Molecular Research Division, Lawrence Berkeley Laboratory, 1 Cyclotron Road, Berkeley, Calif. 94720 Anal. Chem.,53(1981) Effect of Graphite Furnace Substrate Materials on Analyses by Furnace Atomic Absorption Spectrometry 1504
OS
Q H " QS*
O F " Q U " Ql "
Hellma—the largest assortment of highest precision glass and quartz cells. Standard · Flow-through · Constant-temperature Anaerobic · Special Designs Also available-ULTRAVIOLÈT LIGHT SOURCES Deuterium Lamps · Mercury Vapor Lamps Hollow Cathode Lamps · Power Supplies
HELLMA C E L L S , INC.
Write for literature Box 544 Borough Hall Station Jamaica, New York 11424 Phone (212) 544-9534
CIRCLE 98 ON READER SERVICE CARD
Eldex
LABORATORIES
HIGH PRESSURE METERING PUMPS
Eldex
The porosity of the graphite and the fragility of pyrolytic coatings produce many of the problems reported in the literature. Up to 50 μ.% of CaCl2 or CuCl2 suppress the Al signal less than 10%. W. Slavin*. D. C. Manning, and G. R. Carnrick, The PerkinElmer Corporation, Main Avenue, Norwalk, Conn. 06856 Anal. Chem.,53 (1981)· Determination of Insulin in Serum by Enzyme Immunoassay with Fluorimetric Detection 1509 Total incubation period is 45 min and limit of detection is 7.9 pM (46 pg/mL). Values correlate well with radioimmunoassay (r = 0.97). William D. Hinsberg, III, Kristin H. Milby, and Richard N. Zare*, Department of Chemistry, Stanford University, Stanford, Calif. 94305 Anal. Chem., 53 (1981 ) Inductively Coupled Plasma-BASIC Programmable Computer-Controlled Double Monochromator for Sequential Multielement Analysis 1512 The monochromator is directly programmable in BASIC through use of a master-slave microcomputer arrangement. Results of analyses of EPA water quality control reference standards and drinking water samples are reported. James P. McCarthy, Michael E. Jackson, Thomas H. Ridgway, and Joseph A. Caruso*, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221 Anal. Chem., 53(1981) Two-Phase Mixed Indicator Titration Method for the Determination of Anionic Surfactants 1516 The method is extended to compounds containing less than 12 carbon atoms in the hydrophobic group by using 2:3 (v/v) chloroform : 1-nitropropane as the organic phase and a multiple extraction-titration technique. Zhi-ping Li and Milton J. Rosen*, Department of Chemistry, Brooklyn College, City University of New York, Brooklyn, N.Y. 11210 Anal. Chem., 53 (1981)
HPLC PUMP SPECIALISTS •
Flow Rates from 0 . 0 5 - 1 0 0 mL mm
•
Single. Dual & Triple Piston Models
•
Priced from $595
ELDEX LABS
3 5 5 1 Hoven Avenue I M e n l o Park CA 9 4 0 2 5 1 4 1 5 ' 3 Ô 4 - Ô 1 5 9 CIRCLE 63 ON READER SERVICE CARD 1036 A · ANALYTICAL CHEMISTRY, VOL. 53, NO. 9, AUGUST 1981
