Getting started in analytical chemistry: Spectrophotometry and Analysis for R&D

Maybe as a fraction finder for short path but seems like that’s just a substitute for experience…
I’m all ears if there’s more
@AlexSiegel @NoHeatNoVacuum

I’m really interested in your info! I have been trying to teach myself for a little while now, but has definitely been a struggle not coming from a chemistry background


Quality post, thank you for sharing


Are you referring to the usefulness of UV-Vis?

For hemp/cannabis, yes. My understanding is it’s good for systems with only a few components whereas I’ve only worked with complex mixtures in the hemp world. Yes there’s isolate and I suppose you could make a case that a diode array detector on an hplc is spectrophotometry but that’s like saying GC-FID is a flame detection technique (not entirely untrue but lol)

So if you’ve found some interesting ways to use UV-vis I’d like to learn about this as I enjoy spectroscopy

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2005-Spectroscopicdataofcannabinoids.pdf (683.8 KB)

There’s a start. They have UV-Vis spectra for the major 11 or 12 cannabinoids.

A number of terpenes can be distinguished with UV-Vis.


The cannabis industry needs to embrace in-house analytics bad. No one in the food space does not have their own in-house analytics, you have to be able to call the outside labs on their BS. In the food industry, you report a value that doesn’t match in-house testing and they make you run it again. You mess up enough and you lose the business. Same thing needs to be going on to weed out the junk labs.


$120 annually for an individual membership. That gets you access to their library of official methods. Anyone with more than 3 or so different lab instruments should do this.


A big part of conducting proper and reliable analysis are methods, consistency, accuracy, and ethics.

Your methods for both sample prep and using instrumentation should be designed for a consistant and reliable process which yields accurate results with limited deviation. Staff should be well trained, sample prep tools such as micropipettes should be kept in good working order and tested for accuracy. Instruments should be routinely calibrated by qualified individuals, and standards should be stored properly and replaced as needed.

Small mistakes with dilution and calculation can lead to wildly inaccurate results, and this leads into a broader concept…ethics.

In house R&D labs certainly don’t have the same weight in terms of impact of unethical behavior, as 3rs party labs should theoretically catch these mistakes. However your in house lab is the first line of defense in consumer protection, and will have a great impact on the approval and development of products.

It is theoretically in the hands of the analytical technician to influence the outcome of analysis, intentional or not. Perhaps a potential product needs to meet a certain yield or purity to move forward with development, or perhaps you work in a more clandestine setting in which in house analysis is the last checkpoint before public consumption.

Perhaps one may work at an accredited state lab, giving the final call on batches in the legal marketplace.

Results can be influenced in this profession.

It is the duty of those conducting this analysis to work to the best of their ability to conduct precise and ethical analysis regardless of the setting.

Peoples health and mental well being, as well as the reputation and fiscal health of companies, are at stake. Conducting analysis should be a profession of honor, and those who cannot meet that challenge have no place in this setting.


I have 10yrs experience in an analytical chemistry laboratory. I do a lot of chromatography. I specialize in hyphenated techniques. Mainly volatile (flavor and fragrance). But I run gc/ms, lc/ms, ms×ms, 4d-tof chromatography as well. I am Agilent, Shimadzu, Leco, and Waters trained. And write pre&post run macros for many software platforms.

If anyone has any chromatography specific, mass spectrometry specific, or flavor specific questions; I am happy to help.

Just shoot me a dm


Of the brands you have worked with, which do you feel would be easiest for beginners to both use and acquire a used system on a budget?

I’ve only worked with Agilent and Shimadzu, both were quality. It seems as I’ve combed through Ebay and various biotech auction houses that used agilent systems seem to be more common with reasonable price tags.

I’ve worked on waters SFE systems, and aside from the 90 degree angles and piping diameters they were at least robust and well crafted. So I assume that their analytical machines would be comparable, especially in price tag.

Waters also puts on a fair number of conferences and seminars where beginner and intermediate operators would find good information.

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Everyone should also check out LCGC magazine and their cannabis related publications. Lots of helpful techniques and tips there. Also, its good to stay up to date with industry state of art.

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Shimadzu has this industry on lock right now. Agilent is playing catchup. Waters is great mfg for experienced bechtop scientists with LOTS of experience.
I prefer Agilent systems as a whole. I am also biased as an Agilent “power user”.

For the new or budding lab, get a Shimadzu because they make it easy for you. They took their HPLC, stripped it down, preloaded a couple methods, then named it the Cannabis Analyzer…
Also, their 8035 through 8050lcms systems are 0.5 the pricepoint of an Agilent 1200 series. And thats New! With all the training, setup, other bs😂.

With that being said…Agilents are the best. Its hard to beat that HP money and engineering budget. But they draw a premium for it. Better applications help and service also.

Look to used sites like Labx and others to find good deals on used equipment, but for the love of god, get the service plan!!!

Here’s some cheap advise also, go to the mfg websites and see how long instruments have until end if life for parts and such. Biggest problem with cannabis and CBD labs getting used stuff (usually from a second hand company and usually old Agilent) they get something end of life and they find out a year later that they cant get parts or new software is incompatible leaving them stuck in an old bucket of a system.

The longevity of used systems has definitely been one of my larger concerns when looking into them for purchase. Do you have any insight in how often manufacturers tend to move on to a new iteration of software/hardware?

All of the 6890 GC systems for sale are a bad idea rn. Get a 7890 gc it will be good for the next 15yrs. Software migration in 2020. Stay away from 1100 series lc systems (end of life on consumables). Get a 5975c or higher model # for ms systems ( software compatibility issues).

Stay away from the #10 and early 20s for hplc if you can. 10s are obsolete, 20s are getting there. The HPLC 30s are great with alot of life left. Try to get used if you can. The lcms 8030s and higher are ok. But if you want a cheap 1 trick pony check out a new/used cannabis analyzer. Im not big on their gc’s, but if i had to get one, get the 2010 model.

Shimadzu new price is usually close to 5-10yr old Agilent stuff for sale…just an fyi.


Software migrations are few and far between. They are usually driven by OS system changes ( vista to Win7, win7 to win10, etc) withthat said, win 10 rocked Agilents world so all old stuff needs new software or old OS to be functional. And old OS leads to shitty IT support.

The lesson…when you purchase an instrument (new or used) get one that runs the most current Operating system (Windows or Mac) or you will quickly find yourself scrambling to keep it operational with a bunch of patches and such.
Stay out of this position if you can help it!

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Agilent and Shimadzu certainly make fine equipment, but a new SRI 310MM GC provides the same data for a fraction of the price ( 10,495 ) and comes with training, a two year warranty, portability and a built-in hydrogen generator that means no gas cylinders are required.
See this video. - YouTube


A really good book to own if getting into analysis is this one,

“Practical High Performance Liquid Chromatography”

It’s reasonably cheap at around $50 new, and is a very well structured and organized book with a lot of helpful information such as LC vs GC and basics of chromatography. Many folks start off in HPLC/Conventional LC so it’s a good place to start.

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My hemp company uses your GC for internal R&D. Do you have an affordable auto sampler for them? Were really tired of manual injection and need an upgrade before we move up to GCMS

Thank you for putting your time into this. While i havd a good understanding of this havent had it broken down in the format and its has helped my understand testing and the different procedures more clearly