Does anyone have a GC/MS method for analyzing AA in hops?

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KingBrianI

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I'm not sure if this is the right section to post this but it looked as good as any so here goes. I'm wondering if anyone has a GC/MS method for analyzing the alpha acids in hops. I guess I could run a google search but I thought it would be easier and more fun if someone here knew. I analyze agricultural and environmental samples for pesticides every day at work and switching to AA would be a snap. I want to grow my own hops and figure they would be much more useful if I had a hard AA% for them. Anyway thanks for any information!
 

King of Cascade

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If you could accurately calculate the AA of home grown hops you would be the most popular person on this site.
 
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KingBrianI

KingBrianI

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Yeah, lucky for me we have lots of GCs and HPLCs at work. I think the AAs would best be characterized on the GC. Problem is I would need to create a standard curve. I could either source raw AA from somewhere or extract hops of known AA content and use them to construct the calibration curve. Either way an expensive proposition. It's looking like I may have to do some research and either find a published method or attempt to create my own method. Hopefully someone who can help is on vacation today and can provide me with information when they get back and see this.
 

PseudoChef

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I have a protocol for measuring using UV-Vis (I think) if you are interested. I'll have to dig it out of our club archives for you.

If you have a GC/MS and HPLC, I'm sure you have access to a Uv-vis.
 

clayof2day

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Hey Kyle,

I'd be interested in the UV/Vis protocol you have. If you want to email it to me, just shoot me a PM and I'll get you my email. Unless its in my profile, I don't know.

Matt
 
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KingBrianI

KingBrianI

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pseudochef, please post up the method if you find it. i looked around the internet for a bit and found a lc/ms/ms method i can use but i'd like to see other methods as well.
 

david_42

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GC/MS - Gas chromatograph mass spectrometer It's a machine that analyzes chemicals by vaporizing them, separating them by weight (generally by diffusion), and measuring the amount of each weight.
 

seanhagerty

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ok..i had a chance to run my hops through the gcms we use at work..method used prob wasnt the optimal..but i was able to find Alpha myrcene..didnt do a quant method or try to determine conc...am I moving in the right direction?
 
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KingBrianI

KingBrianI

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i don't think alpha myrcene has any effect on bitterness but seeing something is a start. to determine bitterness you need to quantitate for cohumulone and adhumulone.
 

pjj2ba

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I think the alpha acids are not volitile enough as is for GC, hence the more common HPLC methods. Looking at the structures one should be able to methylate them and that would probably reduce the BP enough for GC use. Or you could use your favorite deravitive of choice for aldehydes and/or hydroxyls.

I recall seeing in column manufacturers brochures chromatograms for beer components, but I can't remember if it was LC or GC.
 

Choguy03

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The HPLC method seems pretty straight forword. I will try to see if I can get our chemist to buy some of the stuff so I can make standards. If I do, I will be more then happy to test people's AA% for a small fee.
 
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