PeptideStack
5.2kquestions
20kanswers
220users

purity

Page 34 of 35 · 833 questions tagged purity.

833 questions · sorted by votes · page 34 of 35

3 votes 5 answers7.2k views
What does 96.8% purity on a C18 column actually tell me about a semaglutide vial?

Setup, so nobody has to ask: 96.8% · a C18 column · semaglutide. I would like help reading this properly rather than being told what conclusion to reach. I have the…

hplc
hplc

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

503 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…

833 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…

771 questions
semaglutide
semaglutide

A GLP-1 receptor agonist with a fatty-acid-acylated backbone and a roughly one-week half-life, marketed for type 2 diabetes and for weight…

470 questions
asked by nominal_ten 12k · 5 months ago
3 votes 5 answers6.9k views
What does %RSD on a system suitability run tell me?

I have the report as a PDF with the chromatogram on page two, so I can quote specifics. This is presented as though it settles something, and I am not convinced it…

reference-standard
reference-standard

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

185 questions
hplc
hplc

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

503 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…

833 questions
asked by a_lindgren 58k · 14 months ago
3 votes 5 answers5.1k views
Is a 99.4% result from VendorInvestigate comparable to 98.4% from Janoshik?

The case in front of me: 99.4% · VendorInvestigate · 98.4% · Janoshik. I would like the axes of comparison first and the recommendation second. I have tried the first…

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…

833 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…

910 questions
reference-standard
reference-standard

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

185 questions
vendor-investigate
vendor-investigate

VendorInvestigate, an independent vendor review and verification service. Use this tag for questions about its verification criteria, what a…

113 questions
janoshik
janoshik

Janoshik Analytical, an independent third-party testing laboratory widely used by this community for HPLC purity, identity and quantified content…

139 questions
asked by seven_day_half 31k · 7 months ago
3 votes0 answers3.2k views
Is a 97.9% result from PeptideMeter comparable to 97.6% from Janoshik?

The specifics, since they change the answer: 97.9% · PeptideMeter · 97.6% · Janoshik. The comparison I want does not seem to exist anywhere in a form I can evaluate.…

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…

833 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…

910 questions
reference-standard
reference-standard

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

185 questions
peptidemeter
peptidemeter

PeptideMeter, an independent peptide analytics and vendor-rating service. Use this tag for its published datasets, its rating methodology, and how…

107 questions
janoshik
janoshik

Janoshik Analytical, an independent third-party testing laboratory widely used by this community for HPLC purity, identity and quantified content…

139 questions
asked by swab_stopper 8.8k · 14 months ago
3 votes5 answers2.4k views
Is a 97.1% result from Medutest comparable to 99.1% from Janoshik?

Setup, so nobody has to ask: 97.1% · Medutest · 99.1% · Janoshik. Both of these get recommended confidently by different people, which suggests neither is obviously…

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…

833 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…

910 questions
reference-standard
reference-standard

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

185 questions
medutest
medutest

Medutest, one of four independent testing and verification services referenced throughout this site. Use this tag for its methods, its report…

126 questions
janoshik
janoshik

Janoshik Analytical, an independent third-party testing laboratory widely used by this community for HPLC purity, identity and quantified content…

139 questions
asked by Dr_Ravi_Selvarajah 35k · 3 months ago
3 votes0 answers1.9k views
What counter-ion should I expect on a TFC oral semaglutide lot?

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

acetate-content
acetate-content

Counter-ion content, most often acetate or trifluoroacetate, and why it matters: the counter-ion and residual water are part of the gross mass you…

88 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…

833 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…

476 questions
oral-glp1
oral-glp1

Oral routes for GLP-1 receptor agonism: peptide formulations rescued by absorption enhancers such as SNAC, and true small molecules that need no…

219 questions
asked by void_volume 9.5k · 5 months ago
3 votes0 answers1.8k views
Does a TFA mobile phase change the purity number I get for dulaglutide on a C4 column?

Details up front: a TFA mobile phase · dulaglutide · a C4 column. I suspect the usual explanation for this is wrong, or at least incomplete. I am aware this may have…

hplc
hplc

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

503 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…

833 questions
reference-standard
reference-standard

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

185 questions
dulaglutide
dulaglutide

A once-weekly GLP-1 receptor agonist built on an Fc fusion rather than fatty-acid acylation. Use this tag for questions about the fusion-protein…

200 questions
asked by threadlock7 19k · 8 months ago
3 votes0 answers1.6k views
How do I read an impurity table on a mazdutide certificate against the 96.8% headline?

Details up front: mazdutide · 96.8%. This should be a straightforward calculation and I keep getting two different answers. The numbers are arbitrary; the method is…

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…

833 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…

771 questions
hplc
hplc

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

503 questions
mazdutide
mazdutide

A GLP-1 and glucagon receptor dual agonist developed primarily in China, with a distinct dose range and a fast-moving publication record.…

237 questions
asked by ayo_fadipe 9.4k · 18 months ago
3 votes5 answers1.4k views
Dulaglutide as an Fc fusion — what changes analytically?

This matters because it predicts what a related molecule should do. These are treated as interchangeable and I do not think they are. If both are acceptable I would…

dulaglutide
dulaglutide

A once-weekly GLP-1 receptor agonist built on an Fc fusion rather than fatty-acid acylation. Use this tag for questions about the fusion-protein…

200 questions
mass-spec
mass-spec

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

52 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…

833 questions
asked by eighty_six_hours 20k · 40 days ago
2 votes 5 answers23k views
What does 96.8% purity on a C18 column actually tell me about a survodutide vial?

Stated plainly: 96.8% · a C18 column · survodutide. I have read the primary source rather than the summary, which has left me with more questions. I understand the…

hplc
hplc

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

503 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…

833 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…

771 questions
survodutide
survodutide

A GLP-1 and glucagon receptor dual agonist with a substantial published MASH dataset. Use this tag for its hepatic endpoints, its dose ladder, and…

225 questions
asked by void_volume 9.5k · 2.2 years ago
2 votes5 answers20k views
What counter-ion should I expect on an HJ tirzepatide lot?

What I have: HJ · tirzepatide. The figures are clear enough; the question is what they mean and what they do not. I can supply the numbers if the specifics change the…

acetate-content
acetate-content

Counter-ion content, most often acetate or trifluoroacetate, and why it matters: the counter-ion and residual water are part of the gross mass you…

88 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…

833 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…

476 questions
tirzepatide
tirzepatide

A dual GIP and GLP-1 receptor agonist. Questions here cover the SURPASS and SURMOUNT programmes, the practical differences from a pure GLP-1…

370 questions
asked by Dr_Bram_Verhoeven 84k · 23 months ago
2 votes 5 answers19k views
Is 97.1% a realistic purity ceiling for liraglutide given its chain length?

Concretely: 97.1% · 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…

833 questions
hplc
hplc

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

503 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…

103 questions
liraglutide
liraglutide

A once-daily GLP-1 receptor agonist and the compound that established the class. Still relevant for its shorter half-life, its paediatric and…

235 questions
asked by thermal_mass 13k · 2.3 years ago
2 votes 5 answers17k views
Would you accept 97.1% on tirzepatide from BCH without a content assay?

Conditions: 97.1% · tirzepatide · BCH. I want to decide this in advance so that I am not deciding it under pressure later. Assume I will follow the plan I write down,…

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…

833 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…

476 questions
vendor-vetting
vendor-vetting

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

454 questions
tirzepatide
tirzepatide

A dual GIP and GLP-1 receptor agonist. Questions here cover the SURPASS and SURMOUNT programmes, the practical differences from a pure GLP-1…

370 questions
asked by ahmed_zerouali 15k · 17 months ago
2 votes 5 answers16k views
Would you accept 99.1% on cagrilintide from CPC without a content assay?

Setup, so nobody has to ask: 99.1% · cagrilintide · CPC. I am trying to build something sustainable rather than something thorough that I will abandon. I have already…

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…

833 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…

476 questions
vendor-vetting
vendor-vetting

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

454 questions
amylin
amylin

Amylin and its analogues, most prominently cagrilintide, as a satiety mechanism orthogonal to incretin signalling. Includes the pharmacology of…

237 questions
asked by nominal_ten 12k · 17 months ago
2 votes 3 answers15k views
How does dulaglutide behave on a C18 column compared to tirzepatide?

Setup, so nobody has to ask: dulaglutide · a C18 column · tirzepatide. I suspect the honest answer is that it depends, in which case I would like to know on what.…

hplc
hplc

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

503 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…

833 questions
reference-standard
reference-standard

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

185 questions
dulaglutide
dulaglutide

A once-weekly GLP-1 receptor agonist built on an Fc fusion rather than fatty-acid acylation. Use this tag for questions about the fusion-protein…

200 questions
tirzepatide
tirzepatide

A dual GIP and GLP-1 receptor agonist. Questions here cover the SURPASS and SURMOUNT programmes, the practical differences from a pure GLP-1…

370 questions
asked by nominal_ten 12k · 2.2 years ago
2 votes 5 answers15k views
How do I read a retatrutide chromatogram from Medutest beyond the headline number?

The case in front of me: retatrutide · Medutest. I have read the primary source rather than the summary, which has left me with more questions. I understand the…

hplc
hplc

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

503 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…

833 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…

771 questions
retatrutide
retatrutide

An investigational GLP-1, GIP and glucagon receptor tri-agonist, studied in the TRIUMPH programme. Not approved anywhere. Use this tag for…

251 questions
medutest
medutest

Medutest, one of four independent testing and verification services referenced throughout this site. Use this tag for its methods, its report…

126 questions
asked by mz_4113 101k · 22 months ago
2 votes 5 answers14k views
What does an endotoxin test add for cagrilintide that a purity figure does not?

The particulars: an endotoxin test · cagrilintide. Both of these get recommended confidently by different people, which suggests neither is obviously right. My…

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…

476 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…

833 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…

771 questions
endotoxin
endotoxin

Bacterial endotoxin: LAL and kinetic chromogenic methods, how an endotoxin limit is derived from a dose, why endotoxin survives autoclaving, and…

23 questions
amylin
amylin

Amylin and its analogues, most prominently cagrilintide, as a satiety mechanism orthogonal to incretin signalling. Includes the pharmacology of…

237 questions
asked by Dr_Bram_Verhoeven 84k · 15 months ago
2 votes 5 answers13k views
Does aggregation of a GLP-1 receptor agonist at room temperature show up as a loss of content or of purity?

Setup, so nobody has to ask: aggregation · a GLP-1 receptor agonist · room temperature. The empirical answer seems settled. The explanation does not. If the honest…

peptide-stability
peptide-stability

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

908 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…

476 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…

833 questions
asked by fibre_or_fragment 13k · 19 months ago
2 votes 5 answers11k views
Would you accept 96.4% on cagrilintide from HJ without a content assay?

What I am working with: 96.4% · cagrilintide · HJ. I am trying to build something sustainable rather than something thorough that I will abandon. I have already…

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…

833 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…

476 questions
vendor-vetting
vendor-vetting

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

454 questions
amylin
amylin

Amylin and its analogues, most prominently cagrilintide, as a satiety mechanism orthogonal to incretin signalling. Includes the pharmacology of…

237 questions
asked by dana_wexler 11k · 13 months ago
2 votes 5 answers10k views
What counter-ion should I expect on a BCH mazdutide lot?

What I am working with: BCH · mazdutide. I would like help reading this properly rather than being told what conclusion to reach. I have the full report including the…

acetate-content
acetate-content

Counter-ion content, most often acetate or trifluoroacetate, and why it matters: the counter-ion and residual water are part of the gross mass you…

88 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…

833 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…

476 questions
mazdutide
mazdutide

A GLP-1 and glucagon receptor dual agonist developed primarily in China, with a distinct dose range and a fast-moving publication record.…

237 questions
asked by j_wierzbicki 69k · 16 months ago
2 votes 5 answers9.8k views
Is a 97.6% result from VendorInvestigate comparable to 96.4% from Janoshik?

Concretely: 97.6% · VendorInvestigate · 96.4% · Janoshik. I would like the axes of comparison first and the recommendation second. I have tried the first option 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…

833 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…

910 questions
reference-standard
reference-standard

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

185 questions
vendor-investigate
vendor-investigate

VendorInvestigate, an independent vendor review and verification service. Use this tag for questions about its verification criteria, what a…

113 questions
janoshik
janoshik

Janoshik Analytical, an independent third-party testing laboratory widely used by this community for HPLC purity, identity and quantified content…

139 questions
asked by carys_meredith 12k · 11 months ago
2 votes 5 answers9.7k views
Does aggregation of cagrilintide at 25 °C show up as a loss of content or of purity?

Setup, so nobody has to ask: aggregation · cagrilintide · 25 °C. The empirical answer seems settled. The explanation does not. If the honest answer is that nobody…

peptide-stability
peptide-stability

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

908 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…

476 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…

833 questions
amylin
amylin

Amylin and its analogues, most prominently cagrilintide, as a satiety mechanism orthogonal to incretin signalling. Includes the pharmacology of…

237 questions
asked by nominal_ten 12k · 20 months ago
2 votes5 answers9.6k views
How does survodutide behave on a C4 column compared to tirzepatide?

The case in front of me: survodutide · a C4 column · tirzepatide. These are treated as interchangeable and I do not think they are. If both are acceptable I would…

hplc
hplc

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

503 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…

833 questions
reference-standard
reference-standard

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

185 questions
survodutide
survodutide

A GLP-1 and glucagon receptor dual agonist with a substantial published MASH dataset. Use this tag for its hepatic endpoints, its dose ladder, and…

225 questions
tirzepatide
tirzepatide

A dual GIP and GLP-1 receptor agonist. Questions here cover the SURPASS and SURMOUNT programmes, the practical differences from a pure GLP-1…

370 questions
asked by halvard_ness 69k · 2.3 years ago
2 votes5 answers9.5k views
What does a 99.4% purity with a batch certificate attached let me conclude?

Stated plainly: 99.4% · batch certificate. I have read the primary source rather than the summary, which has left me with more questions. I understand the headline. 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…

833 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…

771 questions
hplc
hplc

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

503 questions
asked by label_claim 30k · 17 months ago