Scientists do their best to answer questions, explain phenomena, or demonstrate a hypothesis, which requires collecting and analysing empirical data. Scientific discoveries are made using various tools – a spectrometer, a telescope, a microscope, a balance scale, a blacklight, or a petri dish, to name a few, create an intuitive approach to analysis, which relies on the ability to read meanings. Spectrometers are the most commonly used scientific tools, present in many disciplines, such as chemistry, biology, and agriculture.
The achievements of science are the foundation for the development and prosperity of society. A spectrometer can significantly affect the quality and success of scientific investigations by allowing experts to understand the composition of stars or examine chemical samples. There are several types of spectrometers, such as fibre-optic spectrometers, mass spectrometers, and nuclear magnetic resonance spectrometers. The wavelength of light is measured over a wide range of electromagnetic spectrum, which describes all the types of light, including those that aren’t visible to the naked eye.
You can’t just put the sample in the machine. Spectrometry is a tricky science, so to say, and to make the most of the analysis’ potential, you must be very careful during sample preparation. Here are our top tips for first-timers:
Eliminate CO2 And Water Vapour from Your Sample
It’s been suggested that exhaled air contains relevant information, so it’s a good idea to limit your breathing near the sample by using a mask that covers your mouth and nose. Inspect it for contamination, tears, rips, holes, and other damage. Equally important is to use atmospheric correction on your software to retrieve accurate and reliable information. Because spectrometer data contains absorption and scattering effects from atmospheric gases and aerosols, the effect must be removed right away.
Use The Appropriate Solutions Grade
The spectrometer is calibrated by comparing the given spectrum to a standard spectrum. All you have to do is load the calibration solution (i.e., a ready-to-use liquid formulation) into a syringe and infuse it into the instrument. Labels are available for easy identification. Chances are you’ve noticed that most of the solutions on the market come in different qualities – or grades if you prefer – and you must use high-purity solvents to obtain the best possible results from the spectrometer analysis. LC-MS grade solvents are slowly but surely becoming a routine fixture in today’s well-equipped lab.
Any impurities in your solvents can have an impact on the accuracy and reproducibility of the results, which is why you should use only high-purity solvents (and blends) designed to meet the requirements of spectroscopy applications. Alkali ions, plasticizers, and surfactants can be found in lower-grade solvents. Indeed, LC-MS grade solvents are expensive, but they’re an integral part of the sample preparation process. Some additives can be used to suppress unwanted signals or selectively boost the signal of specific compounds in the mixture.
Ensure Your Cuvettes Are as Clean as Possible
In case you didn’t already know, clean cells are the basis of spectrometric analysis. If residue is confirmed, you have no choice but to repeat the analysis, so it’s recommended to prevent interference with other substances by making sure the cuvettes are as clean as can be to secure meaningful results. The advantage is the elimination of errors. Never use sulfochromic acid or strong basses, like potassium, as they can damage the cuvettes, so just rinse with purified water followed by ethanol or acetone, and blow dry.
Don’t Place the Highest-Concentration Sample into The Spectrometer
Spectrometers are designed to have a quick measurement speed whilst taking good-quality spectra. If yours isn’t performing up to specs, maybe you should have it replaced, so replace your current technology to improve your overall ROI. Avantes (https://avantes.com/), for instance, produces miniature spectrometers connected via fibre-optic cables, and they have years of experience building customer-specific spectrometer configurations. If your system needs too much maintenance or the device doesn’t meet your expanding requirements, you should buy a new spectrometer.
Back on topic, sample concentration is very important. If the concentration is way too high, it must be adjusted so the peak absorbance is somewhere between 0.3 and 1 because the beam won’t be able to penetrate the specimen. By contrast, if your sample is too dilute, it means the concentration is weak, and, as a result, light will pass through the sample without interacting with the material at all. Put simply, if the sample concentration is too high or too low, there’s something you’re not doing correctly.
Remember It’s All About Timing
Before getting started, consider how much time you need for sample preparation, including collection, concentration, transfer, and disposal, not to mention the collection of data into a presentable format. It will take a while to get the results, even with present-day technology. When examining a liquid sample, work rapidly in case your sample evaporates quickly. Place the sample in a vacuum atmosphere – at reduced pressure, evaporation occurs at low temperatures, so the sample can be concentrated without damage from heat.
Use Internal Standards
An internal standard can be introduced to samples of all concentrations throughout the analysis. The results are calculated by using the peak area ratio, not the peak area of the target analyte, which means that variations in the sampling process or during introduction into the spectrometer can be accounted for because the internal standard will be affected in the same way. Don’t attempt to save money by ignoring internal standards because it can break your experiments. Internal standards are added after sample preparation and before injection to correct for variations.
Wrapping It Up
Different types of spectrometers require varying sample preparation techniques to guarantee optimum analysis, but the tricks presented above will make you a master in any situation. If things do go wrong, avoid fretting about it. By improving the sample, you can improve accuracy, lessen the risk of distortion, and minimise the chance of contamination, so even if it seems like a negligible step, it can have a huge impact on the outcome.
