Chromate | Analytical Services | USA

In fairness to the chemists involved, there is no guarantee that the same sample was tested at each lab.
Yes my comments assume both labs has access to same sample material (samples from same batch, split vial, etc).
 
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Without getting too in the weeds from stats standpoint, @janoshik quotes his HPLC method as 5% margin of error (one sided hence +/- 5?) .

Code:
https://www.janoshik.com/details/

This is probably a 95% confidence interval? He can tell you whether is it +/- 5% or +/- 2.5%.

Let's say axle's test cyp is exactly 200 mg/ml. So we would expect 95% of the time the test would return a measurement between 190 and 210 mg/ml (skipping a bunch of details few want). In this case we don't know what's in the vial. The only way to know who was "righter" would be to send them both a reference standard where we know accurately what the concentration was.

Of course @Axle Labs can tell you what he calculated for his batch based on his measurements which are also subject to error.

TLDR: reassuring the two measurements are within 10%. The uncertainty here combines variability in the instrument (usually low, sample injection) and method prep (usually higher, human error of prepping sample). This is why you have both labs report the results of 10 replicates haha. Everyone would be very enlightened by the distribution.

Exciting.

Postscript: would be useful for both labs to share their method RSV (relative standard deviation) based on internal work. What is your "margin of error", COV, RSV for HPLC quantitative @Chromate ? Don't see it on your site? Example for certain compound is fine. Obviously you have access to reference standards now. No? Yes?
Thus is what I was trying to say haha..
It's bit so much that anyone is right or wrong or better.. just that there is acceptable variances and variations of machines and so forth.

Correct me if I'm misunderstanding.. towards the end your saying each lab would need to take say 20 tests of the same sample and then get the average or mean of that group for a answer? Or am I misunderstanding.

I'll be honest. I want to see this lab be successful. I want to be able to ship inside the US. I don't mind if it then leaves afterwards, that isn't an issue for me. I also believe that it's unhealthy for there to be no competition in this specific market. One lab more or less has a monopoly in this market. I truly believe having a second trustworthy option will benefit "us" tremendously which in return will help us be safer and ensure the quality of what we put in our bodies.
This is in no way meaning any bad to Jano. He has been extremely important and I'm extremely grateful for his service. This is just a personal belief that having more then one option, as long as that option meets standards, will benefit the community as a whole 10 fold.
 
This is such a fun topic I am happy to play messenger:


Now we just need RSD from @Chromate and confirm same material sent to both labs. If both labs will provide replicate number this will allow us to compute z-score and CIs for both labs.

@freedom69 both labs got material from same vial or same batch?

@janoshik has provided his RSD. N = ?

@Chromate : RSD, N?

The link above shows @janoshik 's result is mean value.
 
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Correct me if I'm misunderstanding.. towards the end your saying each lab would need to take say 20 tests of the same sample and then get the average or mean of that group for a answer? Or am I misunderstanding.
When doing method precision work it is typical to do two different evaluations...

1. Instrument precision: prep once and inject 10 times

2. Method precision: take sample to be analyzed and prep 10 separate times (prep replicates). Take each one of those analytical samples and inject.

together these will give you estimates for precision of the instrument and then precision of analyst + instrument.


If you want separate check on accuracy you can also calculate % recovery by spiking a known amount of material into sample and see how much you are able to measure.

I addressed questions above to the labs to help answer your larger question....confidence interval for the measurement from both labs.

Made up Example (Mean with 95 or 99 or whatever you want percentile confidence interval):

Jano: 197 +/- 2 mg/ml
Chromate: 215 +/- 2 mg/ml

In this example if both labs analyzed the same material then someone has an accuracy issue.
 
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@Chromate Expand on your thinking here. If you don't mind?

Perhaps two different batches both with the C48 label? @Axle Labs ?

Might as well get as much info as we can from the excellent effort put in by @freedom69
@freedom69 did not ship the sample to janoshik, so he wouldn't know. And correct, the supplement industry lacks the strict regulations for batch and lot coding which are present in the pharmaceutical industry. New labels can be applied to old batches (to update expiry), or vice versa (to forego the need for new testing).

We will supply the requested data shortly.
 
When doing method precision work it is typical to do two different evaluations...

1. Instrument precision: prep once and inject 10 times

2. Method precision: take sample to be analyzed and prep 10 separate times (prep replicates). Take each one of those analytical samples and inject.

together these will give you estimates for precision of the instrument and then precision of analyst + instrument.


If you want separate check on accuracy you can also calculate % recovery by spiking a known amount of material into sample and see how much you are able to measure.

I addressed questions above to the labs to help answer your larger question....confidence interval for the measurement from both labs.

Made up Example (Mean with 95 or 99 or whatever you want percentile confidence interval):

Jano: 197 +/- 2 mg/ml
Chromate: 215 +/- 2 mg/ml

In this example if both labs analyzed the same material then someone has an accuracy issue.
Ok I believe have a better understanding now.
To the last part on your post. Does one calibrate their machine in a similar way to how one would calibrate a scale? Measure an item that has a known to be exact measurement and compare your reading to actual measurement of said item?
Playing devils advocate .. who's to say both labs aren't wrong?

I would assume there's monthly or yearly checks on the precission of these types of machines,no? Or atleast should be?
They don't have to deal with an organization like Weights and measures dept, using as an example, correct?
 
To the last part on your post. Does one calibrate their machine in a similar way to how one would calibrate a scale?

Similar. Demonstrate linear calibration range. Etc, etc.
Playing devils advocate .. who's to say both labs aren't wrong?
So far we can not. My comment above did not rule that out. Currently we are addressing question around precision, not explicit accuracy.

explaining-difference-between-precision-accuracy.jpg


They don't have to deal with an organization like Weights and measures dept, using as an example, correct?

Correct. You'd prepare standards and calibrate regularly. Spike additions as I mentioned above are also useful for important work.

I'll let the vendors discuss their respective methods. Good questions. This is the type of dialogue we need more of for an informed consumer.

Disclaimer: no conflict of interest with either lab. Just interested observer. Excited we are getting into the weeds a little more.

Happy to provide explicit calculations with the info that is provided by labs.
 
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@freedom69 did not ship the sample to janoshik, so he wouldn't know. And correct, the supplement industry lacks the strict regulations for batch and lot coding which are present in the pharmaceutical industry. New labels can be applied to old batches (to update expiry), or vice versa (to forego the need for new testing).

We will supply the requested data shortly.

Correct sorry for any confusion let me clarify a few things, my two blind samples were only sent from me to Chromate. I utilized Axle because of two reasons 1. I personally use and trust Axles products he’s been a fantastic source for ME personally 2. He test A LOT and I knew this batch already had a Jano report.

Financially I couldn’t justify sending both samples personally to Jano and Chromate so this was the closest thing I could get for us to compare. I appreciate the efforts by Axle, Chromate, and Jano and it’s not a shot or anything at any of them. Being able to utilize a US based testing source without dealing with customs is a plus in my book. I was pleased with both test I received back and I understand there’s going to be a variance between two different testing facilities regardless. This was more giving people an option to see it for themselves and decide if they trust whichever particular testing source.
 
How do i get ahold of Chromates services I've tried two different emails and both return a funky error message?
 
@readalot Apologies for the late submission.
Excellent extra credit work on the tyrosol. A+

Bravo. Your instrument precision is very nice.

What was the RSD and N on the post from this weekend or example method RSD for actual AAS samples (includes sample prep)?

I hope you understand my comments and questions are constructive. I wouldn't be spending time on this if I didn't want all of the analytical labs to be successful and provide quality measurements. Take care.

Edit:

BTW, when you get a functional GCMS set up for residual solvents analysis you will have a lot of business I predict. Same for ICP.

You could also have your chemist do some spikes and share %recovery on AAS example/sample if you wanted to better address the accuracy question. Or maybe do a calibration example. Regardless, you and Jano were pretty close on that sample. For the purists, the spike recovery is always a nice touch.
 
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Bravo. Your instrument precision is very nice.
Thank you.

Not sure how simply changing the compound has any great impact on the precision being demonstrated (except where sample preparation vastly differs, or for uniquely challenging compounds which behave erratically in the column). You should have at least a decent idea of operator error and instrument precision with the data provided.
 
Thank you.

Not sure how simply changing the compound has any great impact on the precision being demonstrated (except where sample preparation vastly differs, or for uniquely challenging compounds which behave erratically in the column). You should have at least a decent idea of operator error and instrument precision with the data provided.
So sample prep is dilute and shoot for potential AAS adulterant in an supplement oil / synthol oil or AAS adulterant in capsule / tablet?

The data shared above gives good indication of instrument precision and operator precision for a dilution (method precision if sample prep is just dilution and injection).
 


Nine commercial supplements were purchased from Holland and Barrett. All the supplements were in tablet capsule or powder dosage form. Each single dosage form was weighed separately. Using mortar and pestle for tablets and capsule shell removing for capsules three tablets or capsules are mixed and homogenized. A portion of powder (50 mg) of from each supplement was dissolved in a solvent mixture of (50:50, v/v) of methanol and ultra-deionized water (50 mL). All samples were sonicated for 20 min at 40°C. An aliquot (10 mL) of each sample solution was filtered by membrane filters (0.22 μm). An aliquot (0.25 UL) of each filtered sample was transferred into 1 mL test tube containing solvent (50:50, v/v) of methanol and ultra-deionized water (0.25 μL). To this solution an internal standard (0.5 mL) of THS(120 μg/mL) was added.



Sample preparation
Oil-based samples were prepared by soni-
cating the appropriate amount (typically 20
μL) in 4 mL of methanol for 20 min and fil-
tering through 0.5-μm or 0.2-μm nylon fil-
ters. Tablets were prepared by sonicating an
appropriate amount (typically between 20
and 100 mg) in 4 mL of methanol and fil-
tering as mentioned above.
 
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