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purity

Page 25 of 33 · 788 questions tagged purity.

788 questions · sorted by votes · page 25 of 33

11 votes0 answers13k views
Is 96.4% a realistic purity ceiling for tirzepatide given its chain length?

Concretely: 96.4% · tirzepatide. I want the working, not the result — I need to be able to redo it with different numbers. I care about the precision as well as the…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
hplc
hplc

Reverse-phase high-performance liquid chromatography, the workhorse purity method. Column chemistry, mobile-phase choice, gradient slope,…

466 questions
peptide-mapping
peptide-mapping

Enzymatic digestion followed by LC-MS/MS to confirm sequence rather than just mass. The method that catches a scrambled sequence or a D-amino-acid…

83 questions
asked by thabo_maseko 20k · 21 months ago
11 votes5 answers12k views
Does dimerisation of mazdutide at 25 °C show up as a loss of content or of purity?

Setup, so nobody has to ask: dimerisation · mazdutide · 25 °C. I keep seeing this stated as a fact with no explanation attached, and unexplained facts make me…

peptide-stability
peptide-stability

The chemistry of peptide degradation: deamidation, oxidation, hydrolysis, aggregation and fibrillation, and how temperature, pH, ionic strength,…

832 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
asked by lane_transit 42k · 13 months ago
11 votes 5 answers10k views
What does 99.4% purity on a C4 column actually tell me about a retatrutide vial?

Conditions: 99.4% · a C4 column · retatrutide. The figures are clear enough; the question is what they mean and what they do not. I can supply the numbers if the…

hplc
hplc

Reverse-phase high-performance liquid chromatography, the workhorse purity method. Column chemistry, mobile-phase choice, gradient slope,…

466 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
coa
coa

Certificates of analysis: what fields a useful one carries, how to tell a real analytical report from a marketing document, batch and lot…

749 questions
asked by mass_shift_18 14k · 2.2 years ago
11 votes 5 answers10k views
Is a 99.4% result from Janoshik comparable to 97.1% from Medutest?

Details up front: 99.4% · Janoshik · 97.1% · Medutest. I want to know what the trade-off actually is rather than which option is fashionable. I would rather have a…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
batch-testing
batch-testing

Testing at the batch or lot level: sampling plans, how many vials from a lot need testing to say anything about the lot, and the difference…

865 questions
reference-standard
reference-standard

Certified reference materials and in-house standards: traceability, the certificate of the standard itself, system suitability, and why every…

179 questions
asked by micron22 36k · 17 months ago
11 votes5 answers7.7k views
Which single measurement would I keep if I could only have one?

I am comparing a supplier certificate against an independent result on the same lot. The failure mode I am trying to avoid is making this decision emotionally. I have…

batch-testing
batch-testing

Testing at the batch or lot level: sampling plans, how many vials from a lot need testing to say anything about the lot, and the difference…

865 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
asked by second_lot 11k · 5 months ago
11 votes 5 answers6k views
How do I read a semaglutide chromatogram from VendorInvestigate beyond the headline number?

Concretely: semaglutide · VendorInvestigate. The figures are clear enough; the question is what they mean and what they do not. I can supply the numbers if the…

hplc
hplc

Reverse-phase high-performance liquid chromatography, the workhorse purity method. Column chemistry, mobile-phase choice, gradient slope,…

466 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
coa
coa

Certificates of analysis: what fields a useful one carries, how to tell a real analytical report from a marketing document, batch and lot…

749 questions
asked by tabular_nums 47k · 16 days ago
11 votes0 answers5.8k views
How does a GLP-1 receptor agonist behave on a C8 column compared to survodutide?

Numbers first: a GLP-1 receptor agonist · a C8 column · survodutide. I have used one of these for a while and I am considering switching, which requires a reason.…

hplc
hplc

Reverse-phase high-performance liquid chromatography, the workhorse purity method. Column chemistry, mobile-phase choice, gradient slope,…

466 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
reference-standard
reference-standard

Certified reference materials and in-house standards: traceability, the certificate of the standard itself, system suitability, and why every…

179 questions
asked by fill_volume 13k · 11 months ago
11 votes5 answers5.7k views
Does oxidation of liraglutide at minus 80 °C show up as a loss of content or of purity?

Conditions: oxidation · liraglutide · minus 80 °C. I want to know whether this is a real physical effect or an artefact of how it is measured. What prompted the…

peptide-stability
peptide-stability

The chemistry of peptide degradation: deamidation, oxidation, hydrolysis, aggregation and fibrillation, and how temperature, pH, ionic strength,…

832 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
asked by retest_please 13k · 8 months ago
11 votes 5 answers5.5k views
Would you accept 97.1% on dulaglutide from MKM without a content assay?

What I have: 97.1% · dulaglutide · MKM. This is a planning question. I know what my options are; I do not know how to weigh them. What I want is the minimum viable…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by stopper_core 50k · 6 months ago
11 votes5 answers5.3k views
Is 96.8% a realistic purity ceiling for tirzepatide given its chain length?

Concretely: 96.8% · tirzepatide. I want the working, not the result — I need to be able to redo it with different numbers. I care about the precision as well as the…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
hplc
hplc

Reverse-phase high-performance liquid chromatography, the workhorse purity method. Column chemistry, mobile-phase choice, gradient slope,…

466 questions
peptide-mapping
peptide-mapping

Enzymatic digestion followed by LC-MS/MS to confirm sequence rather than just mass. The method that catches a scrambled sequence or a D-amino-acid…

83 questions
asked by fresh_bac 13k · 24 days ago
11 votes 5 answers5.1k views
Is 99.1% a realistic purity ceiling for cagrilintide given its chain length?

Stated plainly: 99.1% · cagrilintide. The units are where I keep going wrong, so please be explicit about them. I have sanity-checked the order of magnitude and it…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
hplc
hplc

Reverse-phase high-performance liquid chromatography, the workhorse purity method. Column chemistry, mobile-phase choice, gradient slope,…

466 questions
peptide-mapping
peptide-mapping

Enzymatic digestion followed by LC-MS/MS to confirm sequence rather than just mass. The method that catches a scrambled sequence or a D-amino-acid…

83 questions
asked by w_okoye 40k · 2 months ago
11 votes 3 answers4.6k views
Would you accept 99.1% on semaglutide from WWB without a content assay?

For reference: 99.1% · semaglutide · WWB. I am at the decision point and I would rather think it through than improvise. I would rather spend money on measurement…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by ruaidhri_o_shea 51k · 7 months ago
11 votes0 answers3.4k views
What does a shoulder on the main peak usually turn out to be?

The method section is present, which is unusual enough that I want to make use of it. I have read the primary source rather than the summary, which has left me with…

hplc
hplc

Reverse-phase high-performance liquid chromatography, the workhorse purity method. Column chemistry, mobile-phase choice, gradient slope,…

466 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
peptide-mapping
peptide-mapping

Enzymatic digestion followed by LC-MS/MS to confirm sequence rather than just mass. The method that catches a scrambled sequence or a D-amino-acid…

83 questions
asked by felix_araya 17k · 4 months ago
11 votes2 answers3.2k views
What does 99.1% purity on a C18 column actually tell me about an ecnoglutide vial?

What I am working with: 99.1% · a C18 column · ecnoglutide. I would like help reading this properly rather than being told what conclusion to reach. I have the full…

hplc
hplc

Reverse-phase high-performance liquid chromatography, the workhorse purity method. Column chemistry, mobile-phase choice, gradient slope,…

466 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
coa
coa

Certificates of analysis: what fields a useful one carries, how to tell a real analytical report from a marketing document, batch and lot…

749 questions
asked by juan_esquivel 14k · 5 months ago
11 votes0 answers2.4k views
Would you accept 99.1% on survodutide from KP without a content assay?

The particulars: 99.1% · survodutide · KP. I would like to define my thresholds before I have a result, for obvious reasons. I want a plan with explicit stopping…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by coring_risk 17k · 2 months ago
10 votes5 answers20k views
How does reference-standard error propagate into an ecnoglutide content figure?

The method section is present, which is unusual enough that I want to make use of it. Please show the division. I want to check my own against yours. I would like the…

reference-standard
reference-standard

Certified reference materials and in-house standards: traceability, the certificate of the standard itself, system suitability, and why every…

179 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
asked by coldpack_88 37k · 17 months ago
10 votes 5 answers20k views
How does reference-standard error propagate into a tirzepatide content figure?

This is my second independent submission on material from the same supplier. I would rather understand the derivation than memorise the outcome. Two people I asked…

reference-standard
reference-standard

Certified reference materials and in-house standards: traceability, the certificate of the standard itself, system suitability, and why every…

179 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
asked by pip_okonjo 11k · 13 months ago
10 votes 5 answers19k views
Would an HPLC purity test distinguish aggregation from a synthesis impurity in oral semaglutide?

What I have: an HPLC purity test · aggregation · oral semaglutide. I want to know what the trade-off actually is rather than which option is fashionable. I would…

peptide-mapping
peptide-mapping

Enzymatic digestion followed by LC-MS/MS to confirm sequence rather than just mass. The method that catches a scrambled sequence or a D-amino-acid…

83 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
mass-spec
mass-spec

Mass spectrometry for identity confirmation: electrospray ionisation, multiple charge states, monoisotopic versus average mass, deconvolution, and…

38 questions
asked by mala_venkatesh 21k · 14 months ago
10 votes 5 answers17k views
Is 98.4% a realistic purity ceiling for liraglutide given its chain length?

Concretely: 98.4% · liraglutide. I want the working, not the result — I need to be able to redo it with different numbers. I care about the precision as well as the…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
hplc
hplc

Reverse-phase high-performance liquid chromatography, the workhorse purity method. Column chemistry, mobile-phase choice, gradient slope,…

466 questions
peptide-mapping
peptide-mapping

Enzymatic digestion followed by LC-MS/MS to confirm sequence rather than just mass. The method that catches a scrambled sequence or a D-amino-acid…

83 questions
asked by dmitri_savchuk 17k · 17 months ago
10 votes 5 answers17k views
Would you accept 96.4% on liraglutide from WXT without a content assay?

The case in front of me: 96.4% · liraglutide · WXT. The failure mode I am trying to avoid is making this decision emotionally. I have twelve months in view and I…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by eighty_six_hours 16k · 16 months ago
10 votes 5 answers16k views
Does dimerisation of cagrilintide at 40 °C show up as a loss of content or of purity?

Setup, so nobody has to ask: dimerisation · cagrilintide · 40 °C. I keep seeing this stated as a fact with no explanation attached, and unexplained facts make me…

peptide-stability
peptide-stability

The chemistry of peptide degradation: deamidation, oxidation, hydrolysis, aggregation and fibrillation, and how temperature, pH, ionic strength,…

832 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
asked by Dr_Lena_Ostrowska 42k · 18 months ago
10 votes 5 answers15k views
How do I reconcile 98.2% from Medutest with 96.8% from the supplier?

What I am working with: 98.2% · Medutest · 96.8%. This is not behaving the way I expected and I want to understand the discrepancy before I act on it. I have…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
batch-testing
batch-testing

Testing at the batch or lot level: sampling plans, how many vials from a lot need testing to say anything about the lot, and the difference…

865 questions
coa
coa

Certificates of analysis: what fields a useful one carries, how to tell a real analytical report from a marketing document, batch and lot…

749 questions
asked by second_lot 11k · 12 months ago
10 votes 5 answers12k views
Would you accept 98.4% on ecnoglutide from SGN without a content assay?

The particulars: 98.4% · ecnoglutide · SGN. I would like to define my thresholds before I have a result, for obvious reasons. I want a plan with explicit stopping…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
content-assay
content-assay

Quantified content: how many milligrams of peptide are actually in the vial, measured against a calibrated reference standard. A separate test…

438 questions
vendor-vetting
vendor-vetting

Evaluating a supplier on evidence rather than reputation: testing history across batches, whether certificates are batch-specific, how failures…

436 questions
asked by ekaterina_volk 16k · 12 months ago
10 votes 5 answers12k views
How do I reconcile 98.2% from Janoshik with 99.4% from the supplier?

Details up front: 98.2% · Janoshik · 99.4%. Before I write this off, I want to check whether it is a known failure mode. I have the lot number, the certificate and…

purity
purity

Purity as chromatographic area per cent - the fraction of detected material that is your target peak. It says nothing about how much material is…

788 questions
batch-testing
batch-testing

Testing at the batch or lot level: sampling plans, how many vials from a lot need testing to say anything about the lot, and the difference…

865 questions
coa
coa

Certificates of analysis: what fields a useful one carries, how to tell a real analytical report from a marketing document, batch and lot…

749 questions
asked by mala_venkatesh 21k · 8 months ago