With their ability to identify and measure particle content and concentration in chemical substances, spectrophotometers have proven extremely valuable in research and development in many fields of study, including chemistry, physics, biology, and many other sciences.
Spectrophotometers also play a significant role in the medical and pharmaceutical industries. They help provide the correct doses of drugs and avoid incorrect prescriptions that may expose the patients to danger.
These clever devices ensure a wide variety of products adhere to quality standards by evaluating, controlling, and monitoring the effects of various ingredients and are employed by many laboratory and healthcare organizations such as the World Health Organization (WHO), Food and Drug Administration (FDA), and National Sanitation Foundation (NSF).
Wide Availability and Range of Applications
Testing light is not as difficult as it used to be. Back in the day, spectrophotometers were among the most sophisticated, highly specialized pieces of lab equipment you could get. Testing meant mailing your samples to the lab and waiting for the results for an extended period. Today, a miniature spectrophotometer allows you to perform spectroscopy on-site and see results immediately.
Due to the wide range of applications involving and relying on spectrophotometers, finding the ideal unit to match your goals is imperative. Knowing which types and models are available on the market will help you make an intelligent purchasing decision. The following simple buying guide will help you determine the best spectrophotometer based on your needs.
How to Choose the Right Spectrophotometer
To choose a suitable spectrophotometer for your lab, you must identify your application requirements and the types of analyses you will perform. The following tips should help get you started on the hunt for the best spectrophotometer.
1. Consider the Type of Spectrophotometer Required by Your Application Needs
FTIR and UV-Vis are two of the most widely used spectrophotometry techniques. An Ultraviolet-Visible UV-Vis Spectrophotometer detects and measures the glow of light at different frequencies using ultraviolet light as opposed to the Fourier Transform Infrared Spectrophotometer (FTIR), which uses infrared light.
In addition to analyzing organic and inorganic compounds that demonstrate molecular bond changes, FTIR spectrophotometers can be used to test air and water quality, analyze basic drugs, and identify polymers and plastics.
We recommend FTIR models with an ultra-high optical throughput, excellent signal-to-noise ratio, and multiple spectral ranges (mid-IR, near-IR, far-IR), enabling rapid scanning for faster kinetics. The UV-Vis spectrophotometer can identify impurities in organic molecules and quantify their molecular weight, making it a common tool for forensics, ink manufacturing, and textile production.
2. Think About the Wavelength Range
FTIR spectrophotometers are ideal for applications requiring light across the infrared spectrum of 700–15,000 nm. Suppose you need a spectrophotometer that will measure light over the ultraviolet range of 185–400nm and the visible electromagnetic range of 400–700nm. In that case, a UV-Vis spectrophotometer is the way to go.
If you intend to use cuvettes for the spectrophotometer, consider the material they are made of, as they also have different usable wavelengths. For example:
- Fused Quartz — Ultraviolet wavelengths below 380 nm
- Plastic — Visible-spectrum wavelengths in the 380–780 nm range
- Glass — Visible-spectrum wavelengths in the 340–2,500 nm range
3. Choose Your Configuration (Single- or Double-Beam)
The type of spectrophotometer you’ll need depends on its intended application, whether it is to determine impurities in organic molecules or monitor dissolved content in marine and freshwater ecosystems, for example. A spectrophotometer can either be in a single beam or in a double beam configuration.
A reference standard is used before each measurement is taken on a single-beam spectrophotometer. Compared to double beams, these have a higher dynamic range, are less expensive, easier to handle, and less susceptible to dust accumulation.
Conversely, a double beam spectrophotometer divides a light beam into two different directions. By passing one beam through the sample material and the other through a reference standard simultaneously, these units are faster, more stable, and more flexible than single-beam units.
Spectrophotometers with double beams are recommended for laboratories that must measure and analyze samples quickly. These are also recommended for more complex tests, such as those involving biochemistry analysis of DNA, RNA, and proteins.
4. Consider the Sample Format
You should consider the type of sample, volume, and format you will use before you purchase a spectrophotometer. In spectrophotometry, cuvettes and microplates are the two most common sample formats.
The most common cuvette materials are plastic, glass, and fused quartz. In UV/VIS spectrometers, quartz and glass cuvettes are used for solvents inside and outside the UV range, respectively, while plastic ones are used for solutions.
These are divided into several categories based on their size, but the following two are most commonly used:
- Standard — Used for measuring between 50 ml and 2 ml
- Macro — Used for measurements between 1.5 ml and 2 ml
It is possible to sample multiple substances in small amounts simultaneously using microplates, also called microwell plates or microtiter plates. Microplates are more straightforward and quicker to measure than cuvettes because they have a shorter path length. There are microplates with six to 1536 wells, and each can hold anywhere from a few nanoliters to several milliliters of liquid.
5. Decide on the Type of Sensor
You’ll need to choose the type of sensor and detector you want to use for your spectrometer. Detectors are typically built with a photodiode array (PDA). PDAs will suffice for most routine applications. Some instruments, however, use charge-coupled detectors (CCDs).
A CCD provides very low readout noise but is constructed to absorb UV light. To measure the UV absorption problem, you need a UV-VIS spectrometer.
Semiconductor detectors make sense for wavelengths ranging from 160nm to 1100nm. Such sensors can detect UV, visible light, and shortwave radiation. If you need a detector for 900nm to 1700nm, then Indium Gallium Arsenide (InGaAs) is your best choice.
Ultimately you need to know what you will measure to determine what kind of equipment you will need to measure it.
6. Take Various Practical Concerns into Account
Aside from the technical aspects, there are several factors to consider when choosing the right spectrophotometer for your needs. We will cover each one in the following paragraphs.
When deciding which type of spectrophotometer to purchase, do extensive research and review your budget. The latest technology offered by a new spectrophotometer makes it an excellent investment for people with ample resources, as long as there’s an actual need for all of its advanced functions.
Before purchasing your spectrophotometer, you should also consider the space available in your lab. Spectrophotometers come in various sizes, so consider the size of your workroom when choosing a model.
It’s possible to get spectrophotometers with a PC and a data station if you have a large and open area. Modular size equipment is an option if you have a smaller space.
Optional Features and Ease of Use
Spectrophotometers that include user-friendly software may also be a good option for better data collection, management, and analysis. Invest in a spectrophotometer that is convenient to use and easy to operate to avoid user errors.
Speed and Accuracy
If you want to choose the best spectrophotometer for your lab, you need to consider its accuracy and speed of analysis. An accurate and quick piece of equipment allows for efficient experiments and a more effective analysis thanks to precise data collection.
Be sure to include any unique requirements in your decision-making process. You could be looking for a piece of equipment that can assist you with determining the characteristics of nucleic acids, the presence of DNA and RNA in compounds, and the purity of substances, for example.
Choose your spectrophotometer carefully, taking these particular requirements into account.
In summary, regardless of the types of materials or surfaces that you will be measuring and your overall color measurement needs, there is almost certainly a spectrophotometer solution out there that will ensure the ultimate level of accuracy.
If you choose wisely, you can rely on “by the numbers” measurements, ensuring that each stakeholder’s expectations and needs are met.
Choose the most appropriate spectrophotometer for your application to achieve optimal results. In addition to getting an efficient unit, reviewing the key tips above can help you stretch your resources further.
It is always a good idea to seek professional help and advice from industry experts if you are having trouble choosing the right instrument for your particular application.