ANALYTICAL & LABORATORY EQUIPMENT
Modern technology
has given us automatic instruments to analyse protein and fat
21ST-CENTURY J
ohan Kjeldahl, Michel Eugène Chevreul, Jöns Jacob Berzelius and Franz Ritter von Soxhlet were four gentlemen that worked out defi nitions and methods to measure protein and fat. T eir equipment was rudimentary, and they worked at home with both hot vapours and dangerous chemicals. Today few people, knowing the health aspects, would consider working under these conditions. However, they succeeded to give us the characteristics of protein and fat. Modern technology has given us automatic instruments to analyse these nutrients. Advances such as near infrared technology (NIR) provide fast and reliable measurements but they require correct calibrations to work. Calibrations require previous measurements for comparison, which is easy to solve when there are repeatable analyses. However, this is more
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ANALYSIS
Wet chemistry analyses of protein and fat in food have a 200- year history. Olle Lundström examines whether there can be more improvements to these analyses
challenging and even impossible when the sample composition is unknown. T erefore, NIR instruments are today used widely in food production but not always in research laboratories, where wet chemistry is still needed. T e growth of the NIR instrument
market has been impressive, but unfortunately this has also led to that many believe that wet chemistry is not needed anymore. T is is a belief not only among analysts but also among those companies involved in developing analytical wet chemistry instruments. Specifi c research and development in wet chemistry instruments has therefore been limited. Despite this, innovation in material science and information technology has continued in other areas and new discoveries are now introduced in wet chemistry instruments.
NEW MATERIALS An example of demanding wet chemistry environment is the Kjeldahl digestion, needed for protein determination. A Kjeldahl digestion uses up to 420°C to boil concentrated sulphuric acid, combining high temperature with strong acidity. Plastic material is challenging with the high temperature and at the same time, metal is sensitive to corrosion with the concentrated acid. Most solutions have historically used paint or enamel to protect a metal surface, but they have all their disadvantages regarding protection and durability. New production methods have recently changed this, by making old materials interesting again. Polytetrafl uoreten (PTFE) was fi rst used as a corrosion protection in the 1940s. It was used in the Manhattan Project for an atomic bomb as well as in the fi rst non-stick pans from Tefal. For decades, it was an exclusive material used only when temperature was low enough. However, with new production methods, it is now possible to coat metals with more demanding and specifi c characteristics for heat and scratch resistance. Wet chemistry instruments can therefore be coated also for temperatures above 400°C! New developments in materials have also made it possible to use coatings that give chemical resistance against both alkali and acid simultaneously. T is is an important solution that can now be used in Kjeldahl distillation instruments. Finally, and maybe a little surprising,
development in the car industry has also provided innovations for the wet chemistry laboratory. T e problem with a car travelling on dirty roads, causing corrosion on metal, is not that diff erent from the harsh environment surrounding some wet chemistry instruments. Factories dedicated to supply the car industry with coated metal details are therefore now also coating metal for wet chemistry instruments.
NEW IT SOLUTIONS Wet chemistry and the fundamental methods have not changed, but the information technology and our need to handle data have. Previously it was possible to use paper and pen to take notes and register results, but this is not always possible with new ISO standards and other legal requirements. Most laboratories now require results to be available in a digital format and traceability of activities. Many wet chemistry instruments have been able to connect to computers, using
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