Testing Services >> Infrared Analysis >> FAQ's

Frequently Asked Questions

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How does QTA build calibrations?

The QTA System uses patented technology that enables a spectrometer to be placed at your facility, while the calibration algorithms reside on the QTA Central Processor.  All remote QTA instruments point to these centralized calibrations, thus enabling all algorithms to be developed, maintained, updated and monitored by the QTA Technical team.

What materials can IR and NIR measure?

Infrared spectroscopy is best suited to measuring water and organic components, as well as materials bound to organic components.  In some instances QTA can analyze inorganic components; a feasibility study is performed to confirm this. Mid- IR can be used for homogeneous liquids with detection limits as low as 50 ppm. For solids and inhomogeneous liquids, NIR is used, with detection limits of ~100 ppm.

What is the difference between NIR and IR? 

IR (meaning Mid-Infrared) and NIR (Near-Infrared) correspond to different light wavelengths.  IR covers the spectral range of 2.5 - 25 micrometers and these wavelengths excite molecular vibrations called “fundamental” vibrations. NIR covers the wavelength range of 0.7 - 2.5 micrometers, and causes more complicated molecular vibrations such as bending/stretching combinations; these are called “overtone” or “combination” molecular motions.  Both techniques are nondestructive. NIR is more suitable to analyze the bulk chemistry of the sample (vs. trace components) and inhomogeneous samples.  NIR is also widely used for in-line analysis of production processes; fiber optic probes are used to deliver the light and results are obtained continually, in real time.  IR is used extensively in the lab environment as it is more sensitive to environmental variations in temperature/humidity than NIR.  The calibration development process of both IR and NIR requires a set of calibration samples with traditional laboratory analysis data. QTA technical experts will recommend either IR or NIR based on the application and customer’s analytical needs. 

What is Fourier Transform?

The most common technologies used for IR are either dispersive spectrometers or Fourier Transform (FT) spectrometers. FT systems are much more advanced and have numerous performance advantages over the dispersive instrumentation.  Fourier Transform is a mathematical calculation used to transform a time domain signal into the frequency scale. FT instruments scan the full spectral range faster. FT's high signal to noise ratio and high resolution measurement generates higher spectral quality and better peak resolution, often allowing for more detailed molecular information. FT instruments use a laser to calibrate the wavelength allowing for near perfect wavelength accuracy. On the flip side, FT technology is rather complicated and usually requires chemometric calibrations. QTA offers the expertise in this area as well as years of experience in FT technology. 

Why does QTA use Fourier Transform?

The QTA system is comprised of FT-NIR or FT-IR due to its resolution flexibility and its wavelength accuracy in comparison to other types of NIR systems. Lower resolution settings offer high signal-to-noise ratio for low concentration analysis. Higher resolution settings allow for greater exploration into new capabilities; some applications may require finer spectral detail.  FT instrumentations offer a wide variety of instrument settings that can be tailored to the application. The single resolution feature for other types of NIR systems shows less flexibility than FT-NIR.

Can QTA measure contaminants?

The answer is “Yes”. For some general applications, a low cost IR/NIR may work well. For some existing NIR users with non-FT spectrometers, e. g. diode array or scanning, the QTA service can also be applied. 

Why should I use QTA instead of buying my own spectrometer?

If spectrometers have been around since the 1960's, why aren't they more popular?  The reason is that the technology needs good calibration algorithms to interpret the spectral data.  QTA's calibration algorithms have proven accuracy, precision, and reproducibility.  We continuously validate our calibrations ensuring that the performance is maintained at a high standard.  Attempting to develop and maintain calibrations internally is very resource intensive and costly. A trained technician must be used in order to create robust and reliable calibrations that offer good long term performance. Primary data must be provided for building/expanding the calibrations.  The calibrations must be continuously monitored for shifts caused by raw material changes, instrument drifts or environmental changes, all adding to the total cost. When using the QTA total solution, QTA experts manage, maintain, and validate all of the calibrations at no additional cost. Imagine sending 100 samples out to your trusted lab for primary data to find out that only thirty (30) of them would help improve your calibration. This would be very expensive. QTA chemometricians will provide the highest performance calibrations that are maintained with the minimal cost to the user. With years of experience among our calibration experts, we have acquired a large knowledge base and can overcome the many challenges faced when developing IR applications.

How secure is the data on the QTA server?

QTA takes every precaution to protect your valuable data. During data transmission 128bit encryption is used to secure the transmission and our database is located in a server cluster configuration behind a multi-layered firewall. Third party vulnerability testing is performed on a routine basis.  An authorized username and password is required for access to your data. 

Do you offer training?

QTA will provide you the necessary training you need to start using your instrument immediately.

Can I run QTA without Internet?

Internet-based analysis allows QTA to perform the highest level of service because it allows for:monitoring of your QTA system remotely to ensure peak performance; maintaining and upgrading the calibration algorithms; real time reporting; and remote maintenance. These services all work together to ensure that your quality data is always accurate and reliable.  However, QTA also developed a special system to be used when Internet access is not available or the speed of analysis is a big concern.

What happens if I have instrumentation or technical problems?

If at any time you have operational issues or any questions, we are available for support 24 hours a day (via phone or internet chat) and can help you get back up and running quickly.