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NIR Solutions . . . A periodic newsletter about progress in analytical productivityMaybe it is rocket scienceWe rewrote this introductory piece about thirteen times -- and never failed to sound pompous. But we at LT Industries are friendly folk -- and we like new and neat technology. So, we'll delete the pompous text and simply tell you that Solutions will appear in your mailbox about four times a year. We don't plan to fill a lot of column space with philosophy, but we will tell you about instrumental applications which intrigue us. And why don't you do the same? When you want to communicate an application or ask for someone else's ideas, consider that Solution's columns are open to you. --ed. Recently introducedLT recently introduced three new products. Two of them -- Iso-Chem and Iso-Pharm systems -- are NIR analyzers complete with remotely triggered probes for raw material analysis. Their ease of use features are excellent. Both systems have very low prices. It is that single fact which is opening up a new application area in the NIR world. It is now possible to transfer calibrations developed on a "bench" system to a process instrument quickly and with virtually no risk. Analytical method development groups can build robust statistical models on instruments that are truly inexpensive. The model can be transferred using LTI's "TRANS" software. The development instrument is never outmoded because it can, for instance, be fitted with an optical multiplexer for multiple-point process sensing in a benign environment -- or reserved for additional project developments. All of the "bench" instruments, including vintage Quantum 1200+'s can use the new Freedom Probe™. It's the world's first non-contact NIR diffuse reflectance probe (patent pending). The operator simply moves the gun-shaped probe close to a powder surface. The probe system will indicate when it is within adequate sensing range. The operator then squeezes the trigger and the system acquires spectra for product identity and qualification purposes. The Freedom Probe is expected to have major impact in the pharmaceutical industry and in chemical applications where material integrity is critical. Acid indigestion?What happens when NIR is truly the best choice for end-point monitoring in a semiconductor plant but the chemical bath is sure to digest any metal which has the misfortune to fall in? Simple. Fabricate the probe from acid-resistant polymers. Wait a minute! Optical sensing probes require precise machining and close tolerances -- attributes not generally associated with acid-resisting polymer matrices. But the LT Industries engineers did it. Using the focusing optics of LTI's bubble-shedding technology, they were able to produce a probe which happily takes an acid bath and ignores digestion problems. The acid-resistant probe is reproducible, too. In an ambitious application, a Quantum 2000 process analyzer was fitted with a multiplexer and seven of these probes. Each probe will reside in one of the in-process baths -- and each will experience a slightly different chemical mix. Multiplexed NIR analyzers provide a favorable cost-per-measuring-point value, so the application will not only solve a difficult measuring problem but will also help the plant's bottom line. . . . and More School Days!LTI's well-regarded NIR School is about to convene a new session. Please email us about the dates. The course location is Rockville, MD USA. The NIR School is ideal for instrument or system users who are new to NIR spectroscopy and chemometric model development. Attendance at the School won't get you a gold star, but it will improve the benefits that you attain from your LTI NIR equipment -- and that includes both stand-alone and on-line process equipment. Call or fax Ms. Patricia Johnson, NIR School Registrar, for attendance details. Thankfully yoursWhen you fill your car's fuel tank in the USA next January, you'll have greater confidence in the octane rating which you purchase. If the pump nozzle says 87 octane, it may deliver 88 or 89 octane, but not 86.9! Petroleum refiners don't like to give octane points away -- it's expensive for them and your car may not like it. And new Federal laws in the USA impose stiff penalties on pump octane which is below the rated value. So, how do the refineries control octane? They make motor fuel in vast quantities and in a dynamic process: after all, you can't shut down the refinery while you add a teaspoonful of olefins to "up" the octane value. For years, knock engines have been the primary standard for measuring production fuel octane. Speed and dynamic response is becoming critical, though, so refinery fuel blenders are turning to NIR for its obvious advantages. LTI's PetroScan™ systems are appearing in refineries all over the world. These are multiplexed NIR analyzers with AR-Cells™ at the blending header. The AR-Cell gets its name from Absolute Referencing. It's our unique device which periodically changes the absorbing path length and ratios the resultant values. In this way, the effects of non-sample artifacts, which could cause insidious errors in the measurement, are drastically reduced. Not all motor fuels and their components are measured at the blend header. In many refineries the quality control laboratory does around-the-clock duty to support not only the refinery operating units but also the final product analysis. A PetroScan system is great, but it really isn't made for laboratory use. So, what's a QC chemist to do? LT Industries has a neat little package to solve this problem. It's our Iso-Chem system -- made famous on the front page -- coupled to its own Laboratory AR-Cell™. The resultant system allows QC analysts to pump samples directly from the container, through the specialized cell and into the waste container after the brief analysis time. The system is easy on bench space -- easy on the pocketbook, too -- and very, very productive. Fine, you say. But I don't make gasoline. What can it do for me? Well, consider other fluids which are known to contaminate optical testing systems. Milk. Fermentation broth. Beer. Salad dressing. The Laboratory AR-Cell is designed to withstand abuse -- both chemical and mechanical. Any fluid which can be pumped and replaced by flushing is a candidate for this application. On-line analysis is a natural extension. The field-proven AR-Cell, with its stainless steel construction, is equally at home in food, beverage or fluid chemical process plants. The Numbers GameThe manufacturer's analytical task was to assess the ability of NIR to monitor the composition of polymer pellets -- fresh from the extruder but after cooling and cutting. At first glance, it seemed to be a simple application. The polymer was, after all, a very simple material. Pellets aren't pure polymer, however. They have all sorts of additives, sometimes in nearly trace concentrations. The correlation coefficient for all sample configurations hovered around 0.3 -- hardly correlated at all! Using conventional but old wisdom, the spectra had been converted to the corresponding second derivative for use in the chemometric model. This made for a disappointing review, until the scientists substituted the first derivative. Correlation coefficients immediately jumped to 0.8! While these values should be 0.9+, adjustment of the data pre-treatment was clearly the pathway to success. Is data treatment just an exercise in "fudge factoring"? Not at all. Selection of mathematical ordering algorithms relates both to the nature of the analyte and to its environmental conditions. Concentration, spectral complexity, range of values, interferents and physical parameters all contribute to the ultimate statistical results. As this story shows, model development should include evaluation of data treatments for best figure-of-merit performance. The "Electronic Engineer"No, this isn't a story about an LTI staff member. It's about an inexpensive aid to "up-time" for your NIR analyzer. As long as your instrument-controlling computer has a modem and the appropriate software, LTI application scientists and support engineers can dial in, with your permission, and assess instrument performance. They can also download software updates, evaluate your chemometric model and run diagnostic checks for you. Most new systems from LT Industries are shipped with the requisite equipment. Older systems can easily be upgraded at modest cost and with minimal disruption. You can contact us via fax or e-mail and we'll provide the details. Help us to help you, however. Let us know what peripheral equipment you have installed, the system serial number and the application. A Cake Pan?It may look like one, but it really isn't. We're talking about the RotoKit sampling system. Many LTI system users have the need to sample inhomogeneous materials such as whole grains, shredded textile fiber, fibrous agricultural material, polymer pellets and pharmaceutical tablets. These materials are not only inhomogeneous but also difficult to insert in conventional NIR sampling cells. The heart of the RotoKit system is a big pan which rotates about a large central spindle during spectral acquisition. The entire device is contained in a light-tight enclosure which attaches to the end of the spectrometer -- which, of course, is rotated with its vertical axis up. The pan inserts and removes easily, so workload efficiency is very high. RotoKit samplers are currently being used for tobacco quality control, rice flavor analysis, specification monitoring of polymer pellets and uniformity of OTC tablets. Best of all, the system can be configured for reflectance or transmittance determinations. For subscription information please contact:
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