What is a NIR calibration used for?

NIR calibrations are used for NIR contents analysis as a productive analytical method. That is a two step procedure.
  1. A NIR analyzer does a non-destructive optical scan of a sample that yields a measured spectrum in seconds.
  2. A NIR calibration model can quantitatively predict (analyze, determine, estimate) multiple constituents, ingredients, contents, analytes, assay, API and other parameters and attributes (chemical, physical, biological, biochemical, sensory) summarized as properties, out of a single spectrum in milli seconds.
The NIR analysis is a very fast non-destructive analysis method that can replace or backup slower methods like wet chemical analysis, chemistry laboratory, sensory panels or rheology (viscosity). Or a NIR calibration can open the door to new possibilities of analytics, quality assurance and process control, by developing calibration models for parameters that seems to be impossible, because they are based on human knowledge, empirical values or sensory like taste value. If you have an NIR instrument, you can measure your samples systematically and thus develop your own calibration models.

What are pre-developed NIR pre-calibrations?

There are a lot of terms that means the same, pre-calibration or NIR starter calibration or pre-built calibration or pre-installed calibration orcalibration package or pre-developed calibrations or pre-calibrated NIR or global calibrations or nir global calibration package or factory calibrations or universal near-infrared (NIR) calibrations or local calibrations or ready-to-use NIR calibrations or off-the-shelf calibrations or factory-calibrated or pre calculated model or start-up calibrations or calibration equations or prefabricated nir calibrations or calibration library or mathematical model. That are Calibration models that are prepared and developed by a calibration specialist. They have collected a lot of samples over years and measured them with NIR and analyced it with reference methods. The NIR spectra are then calibrated against the reference values. This is called a NIR calibration or calibration model or sometimes calibration curve or calibration equation. Normally a precalibration is delivered as a file that is compatible to the used NIR analysis software. Such a calibration file does not contain the spectra nor the reference values.

So how can that work?

The only thing that is in the file is a description what it is for (e.g. protein in feed) and the chemometric model that is represented and stored as list of vectors and matrices. You can’t visualize them, it’s a black-box file. You have no insight of how the calibration is done, how are the settings, how is the prediction performance. You can not extend the calibration with your data to adjust it to your purpose or specialty. Most often the pre calibration files are protected, so you can use it only with a paid license to your software or even to your instrument serials number. These are some (not well known) limitations you will discover if you got one. But such starter calibrations are very useful to have a fast and easy start with a new NIR spectrometer. That’s the main reason why pre-calibrations are available. The second reason is that a collection of spectra can be reused to build such pre calibrations.

Predicting the future?

Are very old spectra useful to predict the future? To adjust a calibration model with newly collected data, the calibrations grows and contains more and more redundancy. That means there are very similar spectra with the same concentration range. So which spectra can be removed to make the calibration better? You maybe never ask this because often you hear, that the more spectra you put into a model the better it will be. Why to remove some spectra?
  • reduce not needed redundancy
  • makes the calibration smaller and less complex
  • makes the calibration better fit to the current situation of now and the near future
  • remove long past seasonal data if you have natural products because nature is changing
  • and of course bad outliers should be removed

Custom NIR calibrations

Build your own calibrations that perfectly fit to your specific sample matrix of your products and your preferred raw materials from your local suppliers. Nature grows differently depending on the geographical region, by seasons and year by year. As you know that NIR-Spectroscopy is not an absolute method, then you have to think about to calibrate these current changing effects into your models. If you own the spectra and the reference values then your are able to build your own calibration models and re-calibrate them when needed. So you have the full control on Calibration updates (also known as moving models).

Conclusion

A NIR-instrument can only measure NIR spectra. So the usefulness of NIR comes in with calibrations. That is very important to know when buying such an instrument. For a fast start you can use pre-built calibrations. Good reliably calibrations are offered from third party to quite high prices that level is similar to a cheaper NIR-Instrument! To continue successfully it is highly recommended to develop your own customized calibration (multivariate calibration model) with your own data from your own products, especially with the use of natural resources. Therefore you need knowledge about chemometrics and multivariate analysis (MVA), spectroscopy and the software used to get the calibration optimized. It is worthwhile to create your own calibrations, because you can calibrate product characteristics that are not covered by the proposed pre-calibrations.

The Ghost Calibrator

To explain our service in an other way, I use an analogy between a book and a calibration. Building good calibrations is like writing a good book (a bestseller). You can write in a foreign language (chemometrics) with a high sophisticated word-processor (the chemometric software) that has a grammar checker (an outlier detection). Due to the complexity of the language (chemometrics) and the difficulty of the chosen book topic (the data) and the incomplete automatic grammar checker, you can never be sure if the grammar is correct and may not lead to misunderstanding (bad prediction performance). So the best way is to let a native language speaker check and correct the text. In that way (the analogy), you can see us even as a ghostwriter (a ghost calibration developer, a ghostcalibrator) that helps you, writing the book (with long year experience, consolidated knowledge, time saving, a lot of benefit). The analogy fits very well, because you can define the topic of the book (with your data). Finally you own the calibration and you have the full insight in how it is done. You have it under full control.

NIR Chemometric Software

We develop the NIR calibration models with a manufacturer independent chemometrics software mainly with the widely used and proven methods of PLS and PCR, and supports all common data pretreatments. So with every manufacturer specific chemometric software the model can be used.



This are lists of compatible chemometric software packages:



Chemometric software as a service




Chemometric software bundled with NIR-Spectrometers *


Standalone Chemometric software packages *


*) Disclaimer: We have no affiliation with any of these sites or their companies.



Chemometric Software
Which Chemometric Software are you using for NIR?

NIR Calibrations from scratch

You have already made several NIR measurements and want to see whether it can even produce a workable calibration. You used purchased NIR pre-calibration and are not completely satisfied with their performance and want to see whether your collected data is sufficient to build a better NIR calibration tailored to your application.

Benefit

The NIR Calibration service offers the following benefit: Saving money
  • Improving the accuracy and reliability of already used NIR calibration models have high potential in various manufacturing processes as well as in quality assurance.
  • increased accuracy of analysis => better control of the production process => optimum process flow => better quality => less waste => more throughput.
  • quick and inexpensive to create professional NIR calibration models.
  • relief of their own staff
Time savings
  • for data cleaning (increasing data quality) – missing data, outlier search, wrong data (conflicting information), outlier removal
  • for the search for the optimal NIR model parameter settings (calibration set, wavelength selection, data pretreatments, factor selection)
  • for the calculation of different variations of the model
  • for the validation, evaluation and selection of the optimal model (error, SEP, RMSEP, RMSEC, RPD, fit, R2, bias, slope, …)
  • time-consuming calculation of huge calibration models
  • no long trial and error and waiting in the used NIR software until the calibrations seems to work
NIR analytical accuracy
  • higher reliability due to accuracy and robustness of NIR calibration models
  • the possibility of comparison with your own created or already existing or purchased NIR calibrations
  • what performance increase of analytical accuracy is possible
  • improvement of robustness with respect to change of the product matrix and possible instruments drift
Professional NIR calibration models
  • decades of experience in chemometrics for NIR spectroscopy
  • based on theoretical and applied good practice and know-how
  • application of various guidelines and rules
  • application of vendor-independent NIR chemometric software
  • outsourcing of NIR calibration method development and calibration equation maintenance
  • improving the robustness of NIR prediction model
  • avoid traps and pitfalls of the complicated chemometrics
Detailed results
  • The service provides optimal calibration settings for your NIR data.
  • You get full insight into the NIR calibration, as it is produced and detailed statistical values as a performance index assisted with graphics.

NIR Calibration Service

Services and software for data analysis and analytical modeling for spectroscopy.

This NIR calibration service provides the custom development of optimal quantitative NIR calibration models based on your collected NIR and reference data for vendor independent full range NIR spectrometer analyzers (NIR = Near Infra Red spectroscopy) based on chemometric multivariate methods like Partial Least Square Regression (PLS, PLSR) and Principal Component Regression (PCR).

The key points

The NIR calibration model is decisive for the analysis accuracy.

NIR analysis results make the difference.

Near-Infrared Data Modeling Calibration Service

The problems

Imagine how many publications and literature of NIR spectroscopy (JNIRS) and chemometrics (Journal of Chemometrics) is present.

Did you find the time for the right to designate to read, to study, to incorporate them into practice? Do you have all this knowledge at your calibration developments always present, that you consider anything important, the statistical results, interpret them correctly, analyze the graphs accurately and apply all the tips & tricks of optimizing correctly?

We have the solution for you!

We’ll help you to create and optimize your calibrations. You retain complete control. You have your calibration, with our help, himself under control.

You can view the complete calibration of all the settings down to the smallest detail precisely documented and visualized.

You can also make any changes in the settings. This means you remain independent and have the control in your hand.

We will help you for the time-consuming and knowledge-intensive part. You get the best calibration solution and decide for yourself

Try it and see for yourself