Discussion Category: UV/VIS Spectrophotometers
Laboratory Personnel
Our lab bought a Spectronic 200 several years ago. However from day 1, it doesn't matter the wavelength, the absorbance readings are all over the place. Even when we auto zero, the readings fluctuate. We understand that the spec updates every 2 - 5 secs, however we are no longer sure what reading to take, because at times the variation is so wide. In fact, the readings collected are way too subjective, in that some persons record the most frequent absorbance value after observing for some time, while others record the absorbance value that appears two times in a row. How do we read this spec? What suggestions do you have?
Confused.
Reply byIn Live Display mode the SPEC 200 updates every 2-5 seconds as you say, indicating by the flash that it is presenting a new reading. At low absorbance levels (<1.0A) it should be pretty stable at all wavelengths, varying by no more than 0.003 from one reading to the next after it has had a chance to warm up properly. If you are seeing fluctuations bigger than that it indicates that there is something wrong with that instrument.
Servicing the SPEC200 requires specialized software and fixtures, so you will need to go to Thermo Fisher's technical support team for help in diagnosing the problem and performing a repair.
In you are in the USA or Canada you can contact them by email at: US.techsupport.analyze@thermofisher.com or py phone at 1-800-532-4752. That number is for support on all Thermo Scientific instruments, so you'll have to navigate a phone menu to direct your question to the right team.
If you are outside of the USA and Canada, start by asking the distributor or dealer from whom you purchased the instrument. If they can't help you themselves they will put you in touch with the local Thermo Fisher support group who will be able to help you.
Instruments aren't just beige answer boxes. If you want confidence in your data you need to understand where it comes from.
Reply byYou put really very helpful information.
Reply byHello, I would like to thank you for sharing this useful material. I would recommend you to address the manufacturer of this Spectronic 200.