While many labs may still be using systems from the 1970s, technology has changed and improved considerably for these work-horses of flame-emission spectroscopy. Current systems offer a wide range of elements, autosamplers, custom optic arrays and simultaneous detection across a whole range of elements making the decision rather tricky.
10 Questions to Ask When Purchasing a Flame Photometer
1. What elements do you require analysis for?
Although you’re looking to upgrade your current instrument, bear in mind that the laws of chemistry only allow a handful of elements to be analyzed. Many companies will offer instruments that can analyze Mg (magnesium), Rb (Rubidium) and Sr (Strontium), but ensure you check the operational requirements of these “exotic” elements. For example, the Sr emission band occurs at the same peak to that of Li, useless trying to analyze either if you have or suspect samples containing one or the other. Mg is another of these trick elements, a simple air/propane flame does not reach the required temperature required to excite the atom, acetylene gas is typically used to obtain the higher temperature required but this brings with it the complexity and safety issues around using acetylene, the same can be said for oxygen enriched air. Methods do exist to enhance a propane flame temperature but these require the use of accelerants mixed with the sample and standards. Ensure you pay careful attention to the chemical composition of these as some can have negative consequences when mixed with your samples and standards.
2. Does the instrument offer simultaneous detection and calibration of your chosen elements?
Most flame photometers will require the operator to physically insert wavelength to carry out calibration and analysis over several different elements. This obviously drastically slows your calibration and analysis time and can lead to repeating sample analysis for each element of interest. Leading modern instrument manufacturers will offer not only simultaneous detection and display of the elements but will also offer multiple element calibration within a single standard.
3. How is air provided to the instrument?
The majority of flame photometers run on an air/propane mix. Until recently, flame photometers required additional air compressors sat alongside them in order to operate. External compressors are both noisy and take up valuable bench space, and lead to further sources of error with detection. One market leader responded to these issues from the companies’ origin by building a compressor within the instrument itself. Consider the added cost, maintenance, and service that an external compressor will cost over the years of operation the flame photometer will be in service for.
4. What, if any, accessories are included with the instrument?
Remember that the ticket price may not be the final price you pay. Consider the cost of all the required accessories, standards, and recommended kits you may need to purchase additionally.
5. What sort of software and connectivity are required?
Ensure that the instrument meets the requirements of the lab. Do your protocols state that records must be digital? Manually entering a days’ worth of sample analysis can soon become a costly and ineffective use of time, especially if software exists to automate this process directly from the instrument. Additional output channels such as chart recorder outputs, voltage output in relation to the concentration analyzed, or even a 4–20 mA output are all common features of which the leaders of the flame photometry market will be able to offer.
6. What is the sample throughput and volume size required?
Always ensure that you make allowances when estimating your required throughput to allow for future growth, without the need of an additional instrument. Of course there are the added benefits of using automatic sampling systems, these tend to reduce the amount of samples analyzed in an hour, but they offer the advantages of being almost free from human interference saving time and minimizing human errors. Additionally, if you are working with limited sample volumes, auto-sampler options including built in automatic dilutors tend to work well, even for sample volumes in the 0.05 mL range.
7. Does the instrument offer automatic analysis?
Specifically, can the instrument detect and store a stable reading by itself or does it require human interaction to determine the result. The latter obviously opens up issues regarding quality control issues and user to user error and judgement.
8. What accuracy does the instrument offer?
If the specification doesn’t match your requirements, any other information is useless. It’s important to understand the difference between limits of detection and limits of quantification. Also ensure that if you are planning on purchasing a sampling system to add to the instrument, the specification remains the same.
9. How simple and user friendly is the instrument to use?
Many manufactures now realize the importance of instruments with comprehensible and easy-to-read user interfaces due to their large global potential. A simple user interface can overcome language barriers and is a far more cost effective than an internal language system. Also, a good distributor should provide training and other requirements such as installation.
10. Where is the instrument manufactured?
To some, this may not be of a concern; however, to others this can become a “deal buster.” A confident and reputable manufacturer should be able to provide documentation and certification to prove the source of components and manufacturing facility. Ask for a certificate of origin if you are unsure.
Hopefully, with the help of this paper your next purchase of a flame photometer will be a stress free and relaxed exercise.
Interested in learning more? Why not check out this video compliments of BWB Technologies.
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