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What is TAS True Alignment Spectroscopy

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What is TAS True Alignment Spectroscopy


NIR has changed significantly since it first became commercially available in the 1970's.  Recent technological advances have reduced or eliminated many roadblocks to successfully implementing NIR technology and have allowed many non-technical operators to run very successful NIR programs.

TAS TRUE ALIGNMENT SpectroscopyOne such road block was the process of aligning instruments repeatably and consistently to allow for consistent predictions over time and across instruments with easy calibration transfer.  TAS or TRUE ALIGNMENT® Spectroscopy is a patented process that simplifies this task and provides a traceable and repeatable alignment for Unity instruments for consistent performance and reliable calibration transfer.


'Calibration' is a term that can have two meanings in NIR. The most common use for Calibration is the creation of the mathematical model that predicts the constituent of interest from an NIR spectrum as described in What is an NIR Calibration.  The second type of Calibration refers to the process of aligning the instrument so that the data collected are accurate and repeatable across instruments.  The instrument calibration is also referred to as alignment.

As described in an earlier blog on NIR technology options, each type of NIR technology has strengths and weaknesses.  Unity scientific has chosen the scanning monochromator technology as it offers the highest performance and calibration transfer available, but it is a technology that relies on external standards to properly calibrate the instrument.

Earlier NIR instruments relied on a lengthy procedure involving a master instrument, imprecise standards and sealed natural samples to align instruments.  This procedure was laborious and took time to perform with shipping standards etc.  Additionally, it relied on a master instrument and natural samples, both of which drift.  

TAS Standard CertificateTAS is based on calibrated standards that are traceable to first principle reference materials. Thus the image that TAS instruments are aligned to is fixed and will not change over time.  Aligning instruments in this manner means that the instruments will be consistent and repeatable over time, across instruments, and even across instrument models as new platforms are developed. Additionally, calibrations developed on TAS aligned platforms are future proof and will perform well on any TAS aligned system.


TAS is implemented in Unity Scientific NIR solutions in 2 ways:

  1. All SpectraStar XT instruments are TAS aligned at the factory and come with calibrated TAS standards. If at any time the instrument needs to be re-aligned, any operator can perform this operation on site in about 40 minutes to bring the instrument back to factory specifications.
  2. A TAS performance test is implemented in each SpectraStar XT instrument.  This diagnostic test takes under 10 minutes and ensures that the instrument is properly aligned for reliable performance and results.  
What does this mean to me?

All SpectraStar XT instruments are easy to align and include the tools needed to ensure that the instrument stays in alignment for optimum performance and reliability over time.  Any calibrations developed on TAS based platforms will transfer well across instrument and be compatible with any future platforms that use TAS technology.  

In short, TAS allows any operator to reliably operate an NIR instrument over time with minimal effort and time.