Most frequent questions and answers
NIR spectroscopy is a technique that measures the absorption or reflection of near-infrared light by a sample as a function of wavelength, or wavenumber. The infrared portion of the electromagnetic spectrum is broken up into several regions: the near-infrared, the mid-infrared, and the far-infrared. The boundaries of these regions are not universally agreed upon (astronomers and industrial spectroscopists have good reasons to choose different boundaries, but the explanation is too long to be covered here), but for our purposes the near-infrared region covers the range of wavelengths from the end of the visible spectrum to a wavelength of 2500 nm, or a wavenumber of 4000 cm-1 (wavenumber is the reciprocal of wavelength; depending on the technology used some instruments measure as a function of wavelength, others measure as a function of wavenumber). For most applications, the most useful portion of this range is the longer wavelengths: about 1250 nm to 2500 nm (8000 cm-1 to 4000 cm-1). In this region of the spectrum molecular bonds due to O-H, C-H, C=O, and N-H absorb light. These absorptions are strong enough to be easily measurable, but weak enough to allow significant penetration of the light into the sample (on the order of mm). This makes NIR spectroscopy a very good method for the characterization of a wide range of products, including natural products that are inherently inhomogeneous.
Whether or not NIR spectroscopy can be considered a primary analytical method depends on the application, but for most quantitative applications it is considered a secondary method. This means it must be calibrated using a primary method. The number of samples required for this varies, but is typically in the tens to hundreds, with higher numbers yielding more robust calibrations.
The most common algorithm used for calibrations (by far) is Partial Least Squares (PLS). PLS does require some skill to optimize the calibration, but Galaxy Scientific will help customers with this.
NIR spectroscopy is extremely fast (less than one-minute measurement time) and requires no solvents or reagents. A single measurement can return multiple parameters (e.g. moisture, protein, starch, fat, and ash). Once it has been set up it also extremely easy to operate and does not require a trained chemist or other skilled operator.
NIR spectrometers can be quite rugged and can therefore be used on the factory floor or loading dock. Galaxy Scientific spectrometers are even rugged enough to be field deployable, while retaining the performance of a laboratory system.
A NIR spectrometer can also be coupled to a sampling probe via fiber optics, making the technique very well suited to on-line process monitoring and control. Software is available to fully automate such systems.
In short, improved QC. NIR spectroscopy can be used at all stages of manufacturing or processing, including incoming materials, control of processes, and finished products. Depending on the application, The return on investment can come from many sources, for example verification of incoming materials, better utilization of incoming materials, payment for incoming materials based on quality, rather than just quantity, reduced product failure, better and more uniform product quality, as well as savings in personnel costs or external lab costs.
This depends on the application, but a good rule of thumb is that the detection limit is about 0.1% In some cases it can be considerably better than this, but it may also be considerably worse. One of our experts at Galaxy Scientific can give a better estimate if you contact us and describe your application.
Yes, the following is a list of the various technologies:
Filtometer: Filter Based NIR instrument. This technology uses a filter wheel carrying narrow band pass NIR filters to measure limited number of parameters (mainly moisture). This is a great option when looking for a cost-effective method to measure only moisture.
Scanning Dispersive: AKA grating or scanning NIR spectrometers. Each wavelength is measured one at a time, using a moving grating to select the wavelength being measured. This is then used to construct the spectrum.
Diode Arrays: In a NIR diode array spectrophotometer, each wavelength is measured by a dedicated diode detector. With this technology, all wavelengths are measured simultaneously.
Fourier Transform: An FT-NIR spectrometer uses a system called interferometer to collect a spectrum. This is the latest NIR technology with many advantages. One major benefit of FT-NIR is direct calibration transfer between instruments since the wavelength axis is very precise due to the internal laser.
FT-NIR technology offers bunch of advantages over other available NIR technologies. Below is a list of the main advantages:
- Direct calibration transfer
- High resolution spectra
- Superior sensitivity and SNR
- Better wavelength stability
- Rapid non-destructive measurements
- Instrument to instrument consistency
Galaxy Scientific specializes in the development and manufacturing of high performance, rugged and portable near infrared solutions for lab, process, and field use. Our line of near infrared products is known for its ruggedness and is designed to be taken to the point of need. Our products are suitable for laboratory use, but unlike other high performance NIR spectrometers, they can also be taken into the field, near the manufacturing process line or installed above a conveyor belt for rapid monitoring of multiple parameters.
Beside the technical advantages, all of our NIR products are competitively priced and are known for their fast ROI. They also are available with our unique “Depot Service”.
Galaxy Scientific products were designed to be compact, precise, and economical. Our QuasIR™ Series of near infrared spectrometers use a temperature stabilized solid-state laser that offers a compact configuration, excellent wavelength stability, and a typical lifetime of over 10 years. In addition, our instruments use a special compact lamp that offers a typical lifetime of 20,000 hours and an inexpensive replacement cost. Galaxy Scientific’s QuasIR™ has a wear-free interferometer drive that comes with a 10-year warranty, and user replaceable desiccant.
This compact and rugged design allows us to offer “depot service” meaning our products can be easily shipped via standard shipping methods, without the need for a freight shipment. A product can be overnighted to us, evaluated, and repaired (if needed) upon receipt and then overnighted back to our customer. This is much cheaper and faster than having to send a specialist to the customer site…
There are several factors to consider when purchasing a NIR spectrometer, although not all are applicable in every case. These include cost, performance, spectral range, ease of use, available software, ruggedness, portability, and technical support.