Report for Analytical Chemists
require lurtlier examination to p m point sources of particular dis charges.
KNOW WHAT'S ON YOUR SURFACES?
General Look at Parameters of Water Quality
When examining wastewaters, the objective is to determine the quan tity of materials present t h a t are going to have an undesirable im pact on the receiving waters. F o r example: large discharges of or ganic materials which will support an undesirable level of biological a c t i v i t y ; larger discharges of inor ganic materials which create unde sirable salinity; discharges of nu trients that encourage biological growth; and discharges of trace metals or trace organic materials that have acute or chronic effect on the aquatic ecology and beyond. (Iross discharges of organic ma terials are measured by the non specific parameters of biochemical oxygen demand, chemical oxygen demand, total oxygen demand, and total organic carbon, d r o s s inor ganic discharges are measured by the non.-pecifie parameters of con ductivity or dissolved, nonvolatile solids. or possibly alkalinityacidity measurements. T h e non specific parameters define the gross situation successfully, and the re sults are practical for evaluation of changes in pollutional loads or de termining the general efficiency of wastewater treatment processes. There are subtle aspects in water quality that are recognized as im pacts such as taste and odor of water, chronic toxicity to aquatic life, or the concentrating of haz ardous materials up the food chain. As gross pollution is abated, the subtle aspects become more promi nent. Additionally, the advent of analytical methods o: greater sen sitivity improves the ability to spe cifically identify materials at lower concentration. T h e episodes in volving mercury and pesticides in the environment are examples of impacts that began subtly. Biological laboratory procedures which measure cumulative or chronic impact of low concentra tions of materials (and probably not otherwise identified as ob jectionable ι do not exist. Thus, the actual impact or potential im-
IF Y O U D O N ' T , it could be costing you. T O F I N D O U T , Auger Electron Spectroscopy is the tool to use. It'll tell you the composition of the outer few layers of atoms quickly and accurately. It'll detect all elements except hydrogen and helium with a sensitivity of about 0.1 atomic percent. It's fast enough to monitor dynamic changes via oscilloscope dis play. It can provide accurate in-depth composition profiles when used in conjunction with simultaneous sputter-etching. And . . . a typical system costs less than $50,000. The two Auger spectra below were obtained from two gold plated LEAD frames with distinctly different bonding characteristics. The specimen with poor bonding properties shows distinct thallium contamination while the other does not. Other impuri ties are common to both specimens. Measurement of the indepth distribution of thallium showed that it was localized within 20 A of the surface. Investigation of this problem using any other technique . . . even x-ray analysis . . . would have been next to impossible. With Auger Electron Spectroscopy it was simple and straight-forward.
GOOD BONDING
0
100
200
POOR BONDING
300 400 0 100 ELECTRON ENERGY, eV
200
300
400
I
If you'd like to know what's on your surfaces, you should be checking into Auger Electron Spectroscopy; and for information about Auger spectroscopy, call the people who wrote the book...
Call PHI PHYSICAL ELECTRONICS INDUSTRIES, INC. 7317 South Washington Avenue Edina, Minnesota 55435
(612) 941-5540 T l x : 29 0407
CIRCLE 181 ON READER SERVICE CARD A N A L Y T I C A L CHEMISTRY, VOL. 4 4 , NO. 8, JULY 1 9 7 2
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