A spectrometer is the simplest of scientific instruments. It takes in light, breaks it into its spectral components, digitizes the signal as a function of wavelength, reads it out, and displays it via a computer. A spectrometer is an invaluable tool that can help professionals and amateurs alike extract information from light measurements. Chemists use it to establish the constituents of molecules. Hobby scientists use it to demonstrate infrared absorption by carbon dioxide, which traps greenhouse gasses.
With so many options to choose from, it’s difficult to pick one. To make the right purchase for your research needs, keep in mind these variables when comparing models and brands.
Determine The Minimum/Maximum Sample Size the Spectrometer Can Accommodate
A good sample has flat sides, so you can shine light through it without countless reflections. Spectrometers are tuned differently, meaning that they might require smaller or bigger sizes for preloaded samples. Take into account the sample size needed for molecular analysis. Give particular consideration to the density, shape, and size of the product you want to measure, as your samples may be a better fit for a particular type of spectrometer. Spectrometers can be divided into the following categories:
- Visible light models
- Near-infrared and infrared models
- Ultraviolet/visible spectrophotometers
- Atomic absorption spectrophotometers
- Nuclear magnetic resonance units
- Mercury spectrophotometers/analyzers
You’ll be happy to hear that today’s spectrometers are user-friendly, easy to calibrate, require very little maintenance, and, most importantly, measure a wide array of samples. Still, some instruments are better than others for specific tasks. The size of the spectrometer can be important because you’ll need space to store it. A visible light model, for example, is portable, so it’s a fantastic option for field measurements. Depending on the number of samples and frequency, you’ll have to recalibrate the spectrometer once every three to six months.
Consider The Limits of Detection
The limit of detection can be defined as the smallest measure that can be detected with reasonable certainty for a given analytical procedure. Before choosing a spectrometer, think about the detection limits realizable for individual elements. Simply put, you need to establish how practical an instrument is for your analytical problem. Several detection limits are commonly used, including the instrument detection limit (IDL), practical quantification limit (PQL), method detection limit (MDL), and the limit of quantification (LOQ).
Review your goals and the spectrometer’s detection limits. Depending on your research goals, you can choose between models that distinguish different wavelengths. There are micro spectrometers that measure microscopic samples. They’re suitable for reflectometry, thin-film measurements, and microcalorimetry.
Find Out What Range of Wavelengths the Spectrometer Can Measure
A specific wavelength can be used to determine the concentration of a substance (e.g., protein, fat, and fiber content) or the emission of the fluorescent light to assess the concentration of a specific molecule. Needless to say, spectrometers can vary in wavelengths. What you need is an instrument that has scanning capability and wavelength flexibility. The wavelengths of light absorbed and emitted by each element are unmatched.
The spectrometer’s wavelength range is based on its grating’s ability to disperse onto the detector array. A higher groove density translates into a smaller wavelength range, while a lower groove density leads to a broader wavelength range.
Assess The Spectrometer’s Costs and Any Associated Consumables
What’s your budget for the acquisition? The price of the spectrometer often matches your purchasing choices for other parameters, such as detection limits, wavelength range, and so on. Getting the best value from the instrument requires a good understanding of the spectrometer and its operating abilities. Specify your requirements in sufficient detail and understand why you’re purchasing the machine. You can purchase or lease a spectrometer. The decision comes down to the needs of your laboratory.
It’s recommended to compare the prices of various manufacturers and look into financing options if you’re on a tight budget. Just think about it. You can get access to the highest-end technology. Bear in mind the associated consumables when calculating the total cost of the spectrometer, which deliver reliable performance and maximize the uptime of your investment.
Understand The Spectrometer Measurement Time
The measurement time is essential when determining purchasing choices and costs. The spectrum measurement can be accomplished quickly in the time scale of microseconds. Both accuracy and high time resolution are necessary for observing the dynamic evolution process of the sample’s transmittance spectrum. Whether or not you prioritize a parameter such as measurement time depends on the operational environment. If you work in the educational sector, for instance, you can focus on criteria like data quality and detection limits.
You may be able to reduce the measurement time by reducing both resolution and wavelength. Nonetheless, these changes can lead to losing information unless you have prior knowledge about efficient wavelength and resolution of interest. You can also reduce the number of samples, but it all depends on the settings of the instrument. Keep in mind that there’s a balance between resolution and precision that fulfills your requirements.
Avoid Problems Altogether and Get Accurate Results When Using a Spectrometer
Generally, spectrometers are robust and stable. Every now and then, issues can arise, therefore, leading to unreliable results. Different types of spectrometry errors can occur, such as gross errors, systematic errors, and random errors, to name a few. The most common source of errors is sampling preparation. If the sample is too concentrated or too diluted, it will obscure the readings. This is precisely why samples should always be kept pure. The cuvette also has to be clean. Avoid errors by using the right cuvette.
Now, let’s say a few words about instrument errors. Don’t leave the lid open during measurements, get a proper baseline, and allow the instrument light to warm up. Whatever you do, don’t rush the work because it may lead to inaccuracies. This isn’t to say that lab work isn’t without challenges, but you must find a way to overcome the daily obstacles. Take responsibility for any of your actions that might be part of the problem.