Why Vis/NIR?
Every organic compound carries its own unique spectral “fingerprint” determined by its molecular composition, which can be read by NIR spectroscopy to provide positive identification (qualitative analysis) of different materials (solids and liquids). In addition, quantitative information can be derived from peak intensity, giving a direct indication of the amount of material present.  Modern NIR Spectroscopy allows rapid, non-contact, non-destructive sampling of your materials in a cost effective, easy-to-implement platform, offering a practical alternative to time-consuming wet-chemical and chromatographic techniques.

NIR eliminates the need for the hazardous reagents and time consuming, expensive sample preparation required by Mid-IR and many other analytical methods. NIR analysis provides easy, non-destructive qualitative and quantitative results, requiring little or no sample preparation, whereas significant preparation is required for Mid-IR where transmission measurements require samples, including liquids, be very thin in order to interact successfully with the extremely high absorption coefficients. As an example, these attributes make NIR an ideal tool for detecting counterfeit materials and products.

NIR analysis is cost-effective, consistent, reliable, and meets government regulatory and compliance standards for many industrial applications.

Why ASD Vis/NIR?
ASD is redefining the benchmark for cost-effective, superior NIR instrumentation with our unique and proprietary, Goetz Spectrometer scalable hybrid technologies allowing for wide wavelength coverage (350-2500 nm), which can cover the entire First, Second and combination overtones, as well as the Visible and Third Overtone Regions, giving the most comprehensive wavelength coverage to handle even the most difficult application.

In addition, as a Post-Dispersive style system, ASD technology has opened up a world of “open architecture” external sampling via fiber optics, which enhances its flexibility for sampling. ASD instruments provide superior wavelength, bandpass accuracy, signal-to-noise ratio and photometric performance, outperforming competitive instrumentation by the collection of more in depth and robust data so you get much more reliable analysis.

ASD instruments are designed for durable performance in a variety of conditions and environments, including vibration, and changes in temperature and humidity. The rugged and truly portable design greatly expands the possible scope of applications by enabling analysis at the sample location, whether that be a field, receiving dock, manufacturing floor, warehouse, production line, laboratory, or just about any other imaginable site.

The ASD Hybrid approach features NIR Cooled InGaAs TurboScanner™ technology, which is optimized for the spectral range from 1000 to 2500 nm.  ASD uses special large format, two-stage cooled InGaAs detectors along with high performance original holographic gratings, to give the highest performance capable in a portable system. The system thus provides for:

• Excellent performance on difficult diffuse reflectance samples
• Superior modeling capabilities
• Fast sampling

ASD has now extended its product range to at-line to in-line analysis with industrially designed enclosures to fit in extreme environments as well (link to QSpec iP). ASD’s standard Fiber Optic SMA 905 connector allows for a wide range of external sampling devises, including ASD’s own unique Contac Probe and Hi Intensity diffuse reflectance accessories.

With streamlined user-friendly interfaces to industry leading Chemometrics software (Grams™ and Unscrambler®), ASD provides the platform you need for complete quantitative and qualitative analysis to accelerate quality control procedures and increase your bottom line.

ASD takes customer service to the next level by actually partnering with customers to create dedicated analytical solutions with rapid return on investment (ROI). ASD's solutions maximize manufacturing efficiency and lower risk by ensuring consistent raw material input and in-process, and final product quality. Using ASD Vis/NIR technology in the manufacturing process reduces quarantine delays, cycle times, and costly material waste by providing real-time and validatable, raw material and product testing. In an independent study of the data collected by the FDA's Division of Drug Analysis for the analysis of finished pharmaceutical dosage forms, the ASD LabSpec® Pro tied for first.

Pre-Dispersive versus Post-Dispersive, what’s the difference?
In a pre-dispersive spectrometer, the sample is illuminated with monochromatic light. Light reflected from, or transmitted through, the sample is collected and delivered to the instrument’s detector. Any stray ambient light scattered from the sample is also collected, thus, both the instrument’s monochromatic illumination and all wavelengths of the ambient stray light are delivered to the detector.

In a post-dispersive spectrometer, the sample is illuminated with white light. Light reflected from, or transmitted through, the sample is collected and delivered to the spectrometer where it is first dispersed into it’s component wavelengths and then measured by the instrument’s detector.

Generally two categories of spectrometer performance are affected by Pre versus Post-Dispersive, and in most situations a Post-Dispersive system is advantageous over the Pre-Dispersive system.

Stray light interference
In a Pre-dispersive spectrometer the ambient stray light signal can represent a large fraction of the total light signal measured by the detector, thus, it can be a major source of error. While this error can be minimized by completely shielding the sample from all ambient sources of light, this often precludes the use of most reflectance and transmittance fiber optic probes and non-contact measurement heads.

In a Post-Dispersive spectrometer the ambient stray light scattered from the sample is also collected, but with the post-dispersive instrument only ambient stray light of the same wavelength as that being measured by the detector is added to the signal. Thus, the stray light signal represents
a much smaller fraction of the total light signal measured by the detector resulting in an increase in instrument baseline stability.

Sampling, or sample presentation flexibility
Post-Dispersive spectrometers provide the greatest amount of sampling, or sample interface flexibility. Post-Dispersive systems allow for
non-contact and remote measurements where Pre-Dispersive systems generally have problems with ambient stray light.

For a quick video demonstration of the user-friendly ASD portable and transportable systems, click here. For more in depth information on ASD Vis/NIR analyzers for agricultural/industrial applications click here.

ASD is always looking for new application photos. Send high-resolution images of your research in progress to mktg@asdi.com with Application Photo in the subject line. All photos require a signed Image Release form before we can use them. When possible, photo credits and links to work will be used if that information is provided.