Using handheld analyzers for rapid and non-destructive analysis of raw materials enables quality control managers to test incoming stock and perform checks on products during manufacturing.
Pharmaceutical is a primary target market but the systems can also be used in food analysis to combat fraud.
Steve Saxe said NIR spectroscopy is a non-destructive technique measuring the properties of materials in general.
“It is most useful for organic materials where you have carbon, oxygen and nitrogen. With, what we refer to as an indirect technique, where you develop a correlation between known values and measured values. NIR can be used in the field for a variety of material characterization and quality measurement parameters,” he told FoodQualityNews at Pittcon.
“NIR spectroscopy is good at identifying raw materials and ensuring, for example, the olive oil received on the dock is in fact olive oil and matches or does not match the representation of the supplier.
“It does have some limitations, one of the most important concerns is adulteration or contamination of food and NIR spectroscopy is not particularly well suited to detecting traces or small percentages of contaminants.”
Handheld analyzers for rapid analysis
NIR spectroscopy is most commonly used in food and feed for measuring food oils, protein, carbohydrate, fat content and the nature of different polymers.
The technology has been known for years but had been primarily used in the laboratory and performed on large and expensive instruments.
Viavi’s portolfio includes the MicroNIR Pro - a development tool for a new user assessing feasibility of NIR spectroscopy for their applications, MicroNIR OnSite for use in the field or on the manufacturing floor and MicroNIR Tablet Probe for rapid analysis of individual pharmaceutical tablets and pills as well as single grain kernels and seeds.
Saxe said the Micro NIR instrument can compete with laboratory calibre machines but is adaptable to portable and hand-held applications.
He added the firm is working with partners so customers can use it without having a background in NIR spectroscopy.
Calibration and sampling
Saxe said there are a couple of aspects when it comes to calibration.
“Basic instrument function is the most fundamental calibration. That is easily done by measuring a dark reference and a white reference to bracket the measurement,” he said.
“The other use of the word calibration is in a calibration model or in a chemometric model which is how you, in software, train the instrument to recognize the different materials and the amounts of different materials. Along with the actual sampling technique that is the most aspect of getting high performance out of NIR spectrometers.
“Our NIR spectrometer technology is miniaturized with no moving parts so it is mechanically robust and the fundamental measurement module is only 60g.
“This allows us to design a number of instruments that are readily adapted to manufacturing process lines or to field applications where you can take an instrument out into the field or onto the factory floor and make measurements that otherwise would have to be done in a technical laboratory.”
Saxe gave examples of two modes of operation.
“One is simply classifying, I want to know whether this is olive oil or sunflower oil so you set up a software tool to determine one or the other or say that is an oil I don’t recognize,” he said.
“The other is a quantified model where you want to measure the proportion or fraction of this and that is another capability of NIR spectroscopy and common that our customers will want to know for various mixtures or compounds what percentage of each constituent is in the mixture.
“Certain raw form agricultural products like forage or silage, the composition depends quite heavily on the geographical region, they are different on different continents. So, when building calibration models or NIR tools for these they have to be developed and deployed locally.
“There are many other agricultural products that are more global and to some degree processed and exchanged as commodities globally and the calibration models or chemometric models for those products can be generated and used more globally.”