If you're in A.A. you'd do well to know IL In the rate of our sales, we think we're only second. But in our rate of innovation, we have good reason to think we're first. Here are some items that are new. 1. AA instrument with programmable calculator. Get automatic statistics on precision and linearity, sophisticated curve correction based on those statistics, peak height and peak area measurements with automatic start and stop of integration, and readout of sample concentration in any units, with sample weight and dilution factor taken into account. Meanwhile, you can still use the calculator for everything else that calculators are good for. 2. More versatility—a UV/Vis cell holder. A good AA instrument is so fast that, in many labs, it's used only a couple of hours a day. So IL has introduced a dual cell holder to replace the burner head, and convert your IL AA to a pretty useful UV7 visible spectrophotometer. 3. An ingenious sample treatment system. The IL455 Flameless Sampler comes equipped with little pyrolitic graphite boats. You can put samples into a bunch of boats, do chemical pretreatments, and then insert them one by one into the 455. Recently we have developed a mini-flame unit that uses air and acetylene, which can burn off the sample matrix while leaving the metallic elements. Our first success was in determining vanadium and nickel at low levels in crude oils. You may not even know us. At this point, you may be thinking: "Could these people possibly be second in AA sales, and I haven't heard of them?" Absolutely. Up to now, we've concentrated on certain regions and particular industries. If you want to know who we are... Write to: gjfc
Instrumentation Laboratory Analytical Instrument Division Jonspin Road / Wilmington, Ma. 01887
are available; these spectra must be in reasonable agreement. B. Sample Preparation 1. Liquid State Samples (a). For analytical purposes it is preferable that the sample be run in liquid solution, normally at concentrations in the range 5-10% weight (g) per volume (cc). Solvent bands should be compensated, but not more than 75% of the energy should be removed from the beam by such compensation and then only over a short region of the spectrum. Any solvent bands resulting from incomplete compensation should be indicated on the chart. A suitable solvent combination is carbon tetrachloride (3800-1335, 650-450 c m - 1 ) and carbon disulfide (1350-450 c m - 1 ) ; both solvents should be used at path lengths in the range 0.03-0.3 mm. Cases may arise that require the use of other solvents, and solubility limitations or other concentration dependent factors may necessitate the use of cells of longer path length. These conditions are acceptable provided the reference beam energy is not attenuated by more than 75%. (b). For documentation purposes it is desirable that the spectrum of the liquid be recorded. Solution spectra and liquid spectra are to be regarded as complementary and not as substitutes for one another. (c). The spectra of liquids not soluble in transparent solvents should be measured as capillary films (see II. A). 2. Solid State Samples (a). Solution spectra in the most transparent solvents are preferred, provided the solvents and path lengths can be chosen to leave no significant gaps due to solvent obscuration (see III. B.l.a). (b). For insoluble compounds mulls are preferred to pressed pellets unless it can be established that the pellet gives an undistorted spectrum. Solid state spectra must meet the following criteria: (i) Isotropic materials. The background absorbance should be less than 0.20 near 3800 cm" 1 and less than 0.10 near 2000 c m - 1 . No gross abnormalities should be evident in the background. Compensation in the reference beam by a blank mull or pellet should be indicated, and in no case should it reduce the reference beam intensity by more than 50%. The Christiansen effect should not be apparent, but minor distortion resulting from this effect may be permitted at the discretion of the evaluator. Interference fringes should not be apparent. Pellets should exhibit no bands
CIRCLE 1 0 2 O N READER SERVICE CARD
948 A · ANALYTICAL CHEMISTRY, VOL. 47, NO. 1 1 , SEPTEMBER 1975
THE VOICES OF CHEMISTRY ACS Audio Courses . . . • are state-of-the art courses in chemistry and chemical engineering • consist of a lecture on audiotape cassettes integrated with a course manual • can be used individually or in group situations • are suitable for industrial or academic use • can be purchased on ten-day approval Topics now available include: Applications of Orbital Symmetry Applications of Raman Spectroscopy Basic Gas Chromatography Business Aspects of Chemistry Chemical Reaction Mechanisms Fluorescence and Phosphorescence Spectrometry Fundamentals of Chemical Marketing Fundamentals of Effective R&D Management Gel Permeation Chromatography Intermediate NMR Spectroscopy Interpretation of Infrared Spectra Interpretation of Mass Spectra Introduction to Patents Ion-Selective Membrane Electrodes A Lewis Acid-Base Approach to Chemical Reactivity Modern Liquid Chromatography Modern Organic Synthesis Modern Theory of Acids and Bases Photochemistry of Organic Molecules Practical Technical Writing Principles of Heterocyclic Chemistry Use of Chemical Abstracts
I would like to learn more about the ACS Audio Courses program. Please send me your catalog. name organization address city state
Department of Educational Activities American Chemical Society 1155—16th Street, N.W. Washington, D.C. 20036
