Let’s start with a definition: Transferability is the ability to get the same analytical result on different instruments with the same sample. This is highly relevant to grain analysis where multiple instruments are often used, for example at one grain receival site or across multiple sites in different locations, perhaps with wide environmental variations in temperature and humidity. Transferability is therefore a fundamental part of the Infratec solution.
Transferability is measured on an instrument level and on a prediction level. Repeatability, accuracy of measurements and comparisons from one instrument unit to another are important on an instrument level. On a prediction (calibration) level, the standard deviation of differences in predictions between instruments and the bias or systematic difference in predictions between instruments are key measures.
Correspondingly, transferability is affected by both the instrument hardware, for example, the optics and the sample presentation and by the calibration model. Following our logical flow here, it is therefore necessary to think about both hardware and calibrations when maintaining transferability between instruments. And this is where the Infratec Master concept comes into the picture.
Key elements of the Infratec Master concept
The Infratec Master concept
Both live and artificial samples are important elements of the Master concept in checking performance of Infratec units. Live samples represent what is normally measured, but they are also subject to change. Artificial samples, on the other hand, do not change, but cannot properly measure sample presentation.
The samples are a part of the quality control tests of all new Infratec instruments along with checks on wavelength accuracy and repeatability. These checks are made in relation to the Infratec Master instruments that form the heart of the Infratec Master concept. There are two master units and a master sample set. These are continuously checked against each other. Two instrument units are used in case a backup is required.
The performance of calibrations on the master instrument is then checked with a ring test involving reference laboratories and Infratec results from many grain networks around the world.
Factors describing transferability with respect to predictions
Clearly, the comprehensive nature of the Infratec Master concept is good news for NIR instrument users aiming to minimise running costs with stable instruments and stable calibrations. And there is more good news if instruments are connected in a network that allows proper remote monitoring of instrument performance and calibration updates, i.e. one that lets you look inside a unit, rather than a simple internet connection. With the right network capabilities, monitoring multiple instruments and adjusting or updating calibrations can be performed remotely with minimum fuss in one go from a single desktop.
More about networking solutions can be found here: FOSS Digital Services