NIR Spectrophotometer and Calibration Curve: Differences and Uses

Spettrofotometro NIR e la curva di calibrazione


What is more important between the NIR instrument and the calibration curve? We could answer this question as follows: a good driver will never be first if he does not drive a good vehicle,and a good vehicle will never be first to the finish line if it is not driven by a good driver!

First, you need to know the difference between a NIR spectrophotometer and a calibration curve:

  1. The NIR spectrophotometer does not perform analysis, it only measures the interaction of light energy with the product being analysed.
  2. The calibration curve translates the measured signal into analytical data and must therefore be properly ‘trained’.

Calibration curve: what it is used for and how it adapts to different products

Constructing a calibration curve means collecting many spectra and many analyses in order to represent a product and its variability. Depending on the analytical objective to be pursued, calibrations must be constructed considering the specificity of the products themselves. For example, for a complete analysis of a botanical variety, the curve will in most cases have to be developed specifically for that product, taking into account the variability that it may present in different cultivation sites and its different variants.

This does not mean that it is not possible to develop calibration curves for products which are the result of mixing several components, but it will be necessary to have a database which can represent all the variables which the product may present.

As the popularity of NIR applications continues to grow, the market itself is increasingly directed towards the purchase of ready-to-use solutions rather than products. For this reason, some instrument manufacturers have specialised in the development of systems that include calibration models, bearing in mind that these must be updated and maintained by means of new samples, sometimes collected with the cooperation of the customer. This system creates an international network capable of guaranteeing a continuous renewal of the calibration databases in order to offer all users the best possible experience.