Failing Sulphated Ash Test on CBD Isolate

Testing and Analytics
, , ,
1

Long-time unsigned up lurker here.

We are manufacturing CBD Isolate, to meet USP/EP/German Pharmacopeia monographs we need to test for sulphated ash (https://EP Method 2.4.12).

We are supposed to be getting <0.1% sulphated ash, but are consistently hitting 0.35-0.45%.

Sulphated Ash test shows inorganic impurities present.

cbd sample b
cbd sample b1568×1356 126 KB

Mind you, this CBD has been sitting around for a while. The same peak is present in the distillate, thats also been sitting around and was distilled at high temp (~220C).

We got the heavy metals panel (ICP-MS) back and it was ND for:
Arsenic
Cadmium
Mercury
Lead
Copper
Nickel
Chromium
Manganese
Zinc
Iron
Molybdenum
Boron
Magnesium

We’re at a loss as to what this impurity could be / what could be causing the failed sulphated ash test. We’ll be setting up some alumina experiments next week to see if we can pull whatever it is out. Some kind of inorganic salt?

I haven’t seen any mention of any one running a sulphated ash test here, and the CBD otherwise looks great and the chromatogram looks fine.

Any advice?

Thanks in advance

5 Likes
2

Welcome to the future @WLF!

2 Likes
3

Don t see aluminium , natrium , potasium or calcium in that list :face_with_monocle:
Since you produce the product you might know what steps are you taking after extraction ?
Winterizing , degumming any other steps involving water and or salts ?
Is the extraction solvent pure ?
No bitrex in there ?

2 Likes
4

Distilling at high temps has a major drawback for a lot of hydroxy salts
Since the sublimate to the receiving end or coldtrap

3 Likes
5

I will add those to the next lab panel. Any thing else we should be looking for besides the ones you mentioned already?

Were busy hooking up new equipment/lab and have brought distillation temp down to ~175C i believe. We used hexane for the batch in question but are swapping over to heptane.

I think ethanol temp was around -25C. Then FFE, decarb, distill, hexane crystalization. No degumming.

Ill mention too that were using 304 stainless.

I wonder about the quality of the solvent.

Thanks for answers so far.

1 Like
6

There is merit in waiting until the new set up is complete but if we need to add in a packed column or something id rather know sooner than later

7

The ethanol is ‘food-grade’ and used in the spirits industry, so i dont think there is bitrex.

1 Like
8

Looking at your sop I wonder if your biomass is from highly heavy metal polluted soil then your gona have to call Houston
Yep you would have a problem

2 Likes
9

As in “houston we have a problem?”. That would be fucked. Digging up…an older development batch biomass tested

0.235 ppm Vanadium
0.514 ppm cobalt
0.008 ppm thallium
0.192 ppm Lead
4.733 ppl Nickel

The resulting cbd from it came out clean.

Fucking phytoremediation. Would be a massive pain in the ass since soil differs so much even over a small area.

10

Check for silica,silicium it s a natural hemp compound that will show as inorganic

11

Thanks i will.

12

Could that mystery peak on the chromatogram be silica?? Its not cbdv, ran that today. Or more likely a minor noid? Limited to cbd, cbda, thca, d8, d9, cbn CRMs currently sadly.

13

No doubt any of these inorganic compounds show in the chroma
So what is it my guess is a minor cannabinoid that you cannot test for
I Make several cannabinoid isolated and there is ALWAYs something else in minute amounts

14

Thanks again for all your help so far.

Not asking for a spoon, but is there any way to remediate silica, silicum if thats whats causing the sulphated ash test to fail (considering expanded metals panel comes back negative)? The crucible used for the sulphated ash test is silica…i wonder… but this is the EP method.

Full disclosure i am not a chemist or anything in that realm.

15

We also ran it at an outside lab and got a similar result. Going to another one next week, since both us and the first lab used a burner as opposed to a muffle furnace which can accurately set the temperature at 600C ±50C

16

Come to think off it I have had cbd issolate with a large amount of fats 3-4% wonder if it leaves ash when scorched

1 Like
17

Would fats show up on a chromatogram? And sulphated ash is specifically for inorganic impurities, but perhaps there are ‘exceptions to the rule’?

2 Likes
18

Wondering if we dont need to move away from existing hexane/heptane supplier. I believe its technical grade. I see some shit at the bottom of the barrel.

19

Besides CBDV, the other minor found in CBD isolate is likely CBDB.

3 Likes
20

Thanks. Am I wrong in thinking CBDB is only present in synthetic? I think we actually have a CBDB standard in the lab. Will check and run on Monday.