What Is Nir In Geography

About Our Experts
Originally captured equally office of the Practical Spectral Knowledge Podcast series, this conversation on near infrared (NIR) spectroscopy was led by Yvette Mattley, Ocean Insight'southward Lab Services Manager, and features Ty Olmstead, Vice President, Engineering science and Product Management; Joe Bonvallet, Senior Application Scientist; and our former colleague Troy McKay, a systems engineer and expert in imaging scientific discipline.

Note: These comments have been edited for length and clarity. To hear the complete word, tune in to our NIR Spectroscopy: Proficient Insights podcast.

What is the NIR Wavelength Range?

Yvette Mattley (YM): I've done a lot of piece of work in the UV and Visible wavelength ranges, but it'southward my time at Ocean Insight that introduced me to the NIR. Nosotros talked before the podcast how each of us defines the NIR wavelength range. Then, as a life scientist and biochemist, the NIR wavelength range to me is from just higher up where the Visible wavelength range cuts off – and so, 780 nm out to 2500 nm.

Troy McKay (TMK): Well, my background began in remote sensing. And then, I view the different spectral ranges based on how they're applied in remote sensing. And that means where they fall inside the atmospheric windows: NIR would be from 800-1400 nm and then the SWIR [shortwave infrared] would begin at wavelengths greater than 1400 nm out to 2500 nm.

J oe Bonvallet (JB): To me, it'southward a little scrap different. I like to retrieve of it more in terms of wave numbers. I recall of information technology as a broader range -- 4000 wave numbers out to 14000 wave numbers, where you're looking at aliphatic or aromatic O-H stretches or your amine-type groups.

What are the Advantages of NIR Spectroscopy?

TMK: I take used the NIR and the SWIR extensively because there'south a lot a lot of skilful information in those ranges about chemical composition, soil composition and things that you tin can't actually run across in the Visible. For a lot of chemicals and soils, the Visible spectrum is quite boring and not a lot of features are typically establish there. So, if you're looking to do chemical identification, plastics identification, soil classification and vegetation analysis, you really want to be in the wavelengths greater than 800 nm.

JB: Another big advantage that yous have with NIR is the depth of penetration that you would have compared with your Visible region. If yous're trying to probe into a surface or are looking at the surface chemistry of something and you're trying to look tens of microns into a surface or into the construction of that compound or material, NIR is a groovy technique versus your Visible. Just the biggest disadvantage is yous get some stiff signatures from O-H groups that may be present in water. And and so, if your chemical compound is an aqueous solution of something where you have very depression concentrations of other compounds in a h2o solution, sometimes that O-H tin saturate your signal and tin can wreak havoc on your measurement.

TMK: With NIR, in that location's very little sample preparation to be washed. There's lots of different sampling techniques that can take place. Yous can use flow cells; you can utilise cuvette holders. There are lots of options and it's very flexible in the kind of sampling arrangement that you tin can have, which makes it very useful in a lot of different situations.

Which Applications are All-time for NIR Spectroscopy?

Ty Olmstead (TO): The biggest success I've seen with NIR is in nutrient processing and identifying the quality of food. The penetration depth for organic samples can exist on the guild of a couple of millimeters into the actual products, so we're able to see blemishes or get information below the surface of the food that we're looking at. We've been very successful at Ocean Insight in predicting tomatoes' life spans from the harvester to inside about a solar day of when the actual decay will form on the tomato. This is powerful stuff that can assistance food quality across the world, getting proficient food to people and being able to sort through produce based on different kinds of conditions.

YM: That's my favorite NIR application as well. NIR spectroscopy is a nice, not-destructive way to potentially determine the sweetness of a production or the ripeness of a product without having to cut it open up and destroy it in the process.

JB: In that location's also some interesting stuff with biological applications. I was at a client site where they're looking at different proteins in the drug discovery process and looking in the 4000-6000 wave number range, looking at some aliphatics and aromatic rings out there for the identification of a compound that could potentially be harmful in a drug. So, when you brand these drugs, they're stored in dissimilar containers and sometimes those containers will shed a layer. And that's where you become these aromatic rings in your solution. And and so, this company is looking at quantifying that and seeing if it's harmful to the torso.

YM: Wow. So, we have a lot of specificity out in that location in the NIR as opposed to maybe looking at signals in the Visible, where you're getting color and things that are going to interfere. My favorite way to explain to my family what I do is to talk about oximeter chips. Now they're disposable. Back in the 24-hour interval they were plastic clamps. And in that case, because of the increased penetration depth of the point, and because you lot go a overnice isosbestic betoken that occurs out there with the hemoglobin, the NIR has been a great region for oximetry. But likewise looking for harmful chemicals in therapeutics is some other great application in the biological arena.

TMK: NIR can exist a useful tool for industrial applications where you're looking at dissolved chemicals in aqueous solutions or even in solvents. The nice thing about NIR is yous have some very good, potent signatures out there so y'all can calculate chemical concentrations adequately easily and suspension downwardly the absorption or the transmission spectra into a combination of multiple different chemicals based on their concentrations.

What Tools Are Available to Interpret NIR Data?

TO: One of the corking things that we accept at Ocean Insight is the ability to utilize automobile learning to assist understand what the spectra are telling united states of america as part of the process. We take the product Ocean Intelligence, which actually gives u.s. a powerful tool to assistance in determining things like Brix [a measure of sugars in a fruit] on tomatoes, to figure out how sweet they really are.

JB: With NIR spectra y'all build robust calibration models, and if yous are trying to predict exterior those scale models, it'south non very viable. Collecting all this information, it becomes a question of what practice you do with it and how do you make useful decisions on all this data? And I recollect that's where Ocean Intelligence has a very overnice role in this type of measurement.

YM: Now that we accept machine learning capability in-house, it puts the final piece in the puzzle to make these robust solutions involving NIR spectroscopy or any wavelength range. When you think about the complexity of a tomato plant in terms of a reflection spectrum, it's amazing the actual information content there. But information technology can't be unlocked without some blazon of advanced information processing – chemometrics, motorcar learning, and those types of algorithms. I'yard glad we take that tool here at Ocean Insight.

What are Some of the Keys to Successful NIR Measurements?

TMK: With reflection, I recall fixturing is e'er an issue, no affair which spectral range that you lot're in. So, holding your sample and property your reference in a very precise and repeatable mode is critical to making good measurements, but good practice across the across the board in any sort of reflectance spectroscopy. In the NIR you tin however employ Spectralon® or PTFE standards, which are nigh Lambertian and very high reflectance, which makes them excellent standards to use virtually downwardly into the UV all the manner out through the 2500 nm range.

YM: In my experience, working in the NIR requires a lot of light to get a good signal to dissonance ratio because of the inherent noise associated with the detector. I'one thousand wondering if you guys have seen similar challenges, and if you accept suggestions for how we can overcome that.

JB: As you mentioned, one of the big issues in the NIR is that dissonance floor and keeping that under control. So, we always try to go every bit much calorie-free into the detector as possible. And there are lots of tricks you lot tin can play to do that. Also, ane of our newer products, the NIRQuest+, achieves this. With NIRQuest+ we get more than light into the system, allowing us to achieve lower detection limits and higher throughput.

TMK: As well, I've always had to use quartz halogen-blazon light sources for the NIR, which is a challenge. They are not always the about meaty. They brand a lot of estrus. But recently, I've noticed some applications where you lot tin can get some lite from an LED in the broadband infrared region. That's slap-up news because LED power levels are relatively depression, and NIRQuest+ will allow us to utilize them a little flake more than.

YM: What about dealing with sample mixtures? Accept you found that deconvoluting those signals, the spectral signatures, which are so complex, is easier when you get out into the NIR?

TMK: Yep, provided the features are stronger and higher frequency. Y'all don't want to run into a gradually changing, really smoothen signature, otherwise you're going to confuse your computer model much simpler than if yous accept overnice, singled-out, sharp absorption features, which tends to exist the case out in the NIR.

What volition be the About Exciting Developments in NIR Measurements?

JB: I think it has to practise with the biologics, especially in the time we're living in, in this drug discovery phase, being able to kind of go that fingerprint of what is in your solution, peculiarly equally vaccines are developed for COVID-nineteen. I remember there are going to exist a lot of applications in this area for this type of measurement.

Also, NIR allows us to make measurements in situ in different processes, such as the drug discovery. It allows us to make GMP-blazon measurements where we're non interfering with that solution, and we're able to interface with it and make certain that things going into the trunk are safe.

TMK: I think vegetation, crop wellness and food in full general are good applications for the NIR that I'm excited to see where they get. The Vegetation Index was one of the first things they did with the NIR back in the '60s, just looking at vegetation health. That'southward come up a long way since then. And with the size of spectrometers shrinking and the size of hyperspectral imagers shrinking, they tin can exist used a lot more in agriculture to ensure that the crops are getting the proper amounts of nutrients and pesticides.

TO: The most exciting infinite for me with the NIR and SWIR is their continued introduction into commercial processes. As nosotros beginning to think about how nosotros motion food or move different substances into production to get information technology to the masses, NIR gives usa a tool on which we can discriminate and make decisions well-nigh quality.

When Joe is talking about using NIR for drug discovery, that's going into a larger manufacturing procedure where we're going to need to make decisions on very large volumes of material. When Troy is talking nigh nutrient quality, nosotros think about the food we meet at the grocery store before taking it dwelling house. Just earlier that nutrient e'er gets to the grocery shop, there are massive amounts of processing of onions, tomatoes, pomegranates and more. And decisions need to exist made of how is that food is to be distributed in the all-time style to give everybody the all-time quality they can. And I think that NIR and SWIR really unlock the space to give us a new way into making better decisions almost how nosotros take care of our planet.

Using NIR Spectroscopy for Soil Characterization

Measuring soil composition with a nigh-infrared diffuse reflectance organisation helps characterize soil quickly, economically and finer. In this demo, we use the NIRQuest+2.5 NIR spectrometer as role of a lengthened reflectance system for soil analysis.

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