switched from 1.0mg to 0.5mg and the sulphur burps got better, not worse
I have had 22 orders now and I keep a table, so here is the honest summary rather than a vibe.
Material has been consistent. Communication has not. Shipping has varied by about 12 days on nominally the same lane, which matters more in summer than in February.
The independent number came back 99.0% against a claimed 98.0%, which I read as agreement rather than a discrepancy — inter-lab variance on this assay is a point or two either way and treating one lab as ground truth is how people end up in pointless arguments with vendors.
Batch number is in the comments. Ask if you want the method.
best — the order this archive was captured in
Strongly agree. Largest single impurity tells a different story than total purity.
That is net peptide content, not purity. Different number, different meaning.
the gradient is doing the separation work, not the column alone
chromatogram or it did not happen
Edit to your parent would help — the concentration you quoted assumes one scenario and you have written another above it.
Small correction: the trial was 7 weeks, not 29. Does not change your point but people will quote it.
This is the correct method framing. Column and gradient are load-bearing fields.
Not convinced. The evidence does not support that reading.
area% and mass% are not the same and this whole post conflates them
integration decision on a shoulder changes your number by half a point on its own
Detection wavelength? purity and that changes at different wavelengths.
area% and mass% are not the same and this whole post conflates them
Slight fix: the number was 97.6, not 95.1. Decimal point, but a fairly consequential one.
the gradient is doing the separation work, not the column alone
A shoulder on the main peak that 10 analysts integrated 38 different ways. Same trace, 96.8 spread.
instrument quality is less important than analyst consistency
This is the "correlation is mechanism" thing again. You changed three variables at once.
related substances are where the story lives, not the main peak
Did they post the raw trace or just the summary?
Retitled to remove editorialising. Put the evidence in the body.
state the method: column, gradient, detection wavelength, injection volume
integration decision on a shoulder changes your number by half a point on its own
Injection volume and flow rate? Those affect resolution.
related substances are where the story lives, not the main peak
The Janoshik result being close to my own HPLC is the signal, not the absolute number. Both are right.
Crossposting this to c/progresspics because the people who need it are not reading this community.
area% and mass% are not the same and this whole post conflates them
two labs, two different baselines, two different purity numbers, both honest
- 1Strongly agree. Largest single impurity tells a different story than total…13 comments in this branch · started by u/cormac_roos
- 2A shoulder on the main peak that 10 analysts integrated 38 different ways.…5 comments in this branch · started by u/sig_figs_sam