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hplc

Page 16 of 20 · 466 questions tagged hplc.

466 questions · sorted by votes · page 16 of 20

10 votes 4 answers7k views
What does a 97.1% purity with a batch certificate attached let me conclude?

Setup, so nobody has to ask: 97.1% · batch certificate. I have read the primary source rather than the summary, which has left me with more questions. I understand…

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
hplc
hplc

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

466 questions
asked by siobhan_deasy 16k · 6 months ago
10 votes 5 answers4.7k views
Is 95.2% a realistic purity ceiling for mazdutide given its chain length?

What I am working with: 95.2% · mazdutide. The units are where I keep going wrong, so please be explicit about them. I have sanity-checked the order of magnitude 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
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 Dr_Fatima_Belkacem 52k · 42 days ago
10 votes 3 answers4.6k views
What does a 97.9% purity with a batch certificate attached let me conclude?

Stated plainly: 97.9% · 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…

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
hplc
hplc

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

466 questions
asked by kelvin_lam 11k · 2 months ago
9 votes5 answers18k views
How does cagrilintide behave on a C8 column compared to tirzepatide?

Details up front: cagrilintide · a C8 column · tirzepatide. I have used one of these for a while and I am considering switching, which requires a reason. What I care…

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 fib4_reader 35k · 2.2 years ago
9 votes 5 answers16k views
What does 98.8% purity on a C8 column actually tell me about an oral semaglutide vial?

What I have: 98.8% · a C8 column · oral semaglutide. I can parse the result. I am less sure what it licenses me to conclude. I have deliberately not looked at anyone…

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 Dr_Tomas_Kral 37k · 23 months ago
9 votes5 answers16k views
Why does racemisation accelerate at room temperature rather than proceeding linearly?

Details up front: racemisation · room temperature. I suspect the usual explanation for this is wrong, or at least incomplete. I am aware this may have a boring…

peptide-stability
peptide-stability

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

832 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
hplc
hplc

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

466 questions
asked by imani_dube 19k · 17 months ago
9 votes 5 answers15k views
Why does racemisation accelerate at minus 20 °C rather than proceeding linearly?

Details up front: racemisation · minus 20 °C. I suspect the usual explanation for this is wrong, or at least incomplete. I am aware this may have a boring answer. I…

peptide-stability
peptide-stability

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

832 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
hplc
hplc

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

466 questions
asked by marta_szymanska 17k · 2.1 years ago
9 votes5 answers14k views
Does racemisation dominate for dulaglutide held at minus 80 °C?

What I have: racemisation · dulaglutide · minus 80 °C. I suspect the usual explanation for this is wrong, or at least incomplete. I am aware this may have a boring…

peptide-stability
peptide-stability

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

832 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
hplc
hplc

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

466 questions
asked by Dr_Fatima_Belkacem 52k · 18 months ago
9 votes 5 answers11k views
How does tirzepatide behave on a wide-pore C18 column compared to mazdutide?

The specifics, since they change the answer: tirzepatide · a wide-pore C18 column · mazdutide. The comparison I want does not seem to exist anywhere in a form I can…

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 ilaria_bertone 43k · 9 months ago
9 votes4 answers9.6k views
Does aspartimide formation dominate for liraglutide held at 25 °C?

The case in front of me: aspartimide formation · liraglutide · 25 °C. I want to know whether this is a real physical effect or an artefact of how it is measured. What…

peptide-stability
peptide-stability

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

832 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
hplc
hplc

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

466 questions
asked by a_lindgren 46k · 7 months ago
9 votes0 answers8.8k views
Is 99.1% a realistic purity ceiling for mazdutide given its chain length?

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

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 esther_vandeVelde 49k · 15 months ago
9 votes0 answers3.4k views
Does oxidation dominate for oral semaglutide held at 2–8 °C?

The case in front of me: oxidation · oral semaglutide · 2–8 °C. This is one of those things that everyone repeats and nobody derives. This matters practically, not…

peptide-stability
peptide-stability

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

832 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
hplc
hplc

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

466 questions
asked by forty_units 14k · 7 months ago
9 votes 3 answers3.4k views
What does 97.6% purity on a C4 column actually tell me about a dulaglutide vial?

Concretely: 97.6% · a C4 column · dulaglutide. I would like to know the limits of what can be inferred from this. What I am trying to avoid is over-reading a single…

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 · 7 months ago
9 votes0 answers2.9k views
Does aggregation show up on HPLC or do I need SEC?

This is a recurring problem with one particular shipping lane rather than a one-off. I suspect the honest answer is that it depends, in which case I would like to…

peptide-stability
peptide-stability

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

832 questions
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
peptidemeter
peptidemeter

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

14 questions
asked by esben_lykke 15k · 4 months ago
8 votes 5 answers21k views
Does aspartimide formation dominate for liraglutide held at 40 °C?

Conditions: aspartimide formation · liraglutide · 40 °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
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
hplc
hplc

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

466 questions
asked by mz_4113 99k · 2.3 years ago
8 votes5 answers21k views
How do I read an HPLC chromatogram beyond the headline number?

The method section is present, which is unusual enough that I want to make use of it. I would like to know the limits of what can be inferred from this. What I am…

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 vial_five 15k · 20 months ago
8 votes 5 answers19k views
Why does dimerisation accelerate at 4 °C rather than proceeding linearly?

What I am working with: dimerisation · 4 °C. The empirical answer seems settled. The explanation does not. If the honest answer is that nobody knows, I would rather…

peptide-stability
peptide-stability

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

832 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
hplc
hplc

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

466 questions
asked by deamidation_watch 43k · 2.1 years ago
8 votes 5 answers18k views
Does hydrolysis dominate for dulaglutide held at 40 °C?

Details up front: hydrolysis · dulaglutide · 40 °C. I can predict the outcome but I cannot explain it, which means I will get the next case wrong. I would like to…

peptide-stability
peptide-stability

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

832 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
hplc
hplc

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

466 questions
asked by ines_delacruz 16k · 14 months ago
8 votes 5 answers15k views
How does survodutide behave on a C4 column compared to mazdutide?

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

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 samir_bennani 13k · 2.1 years ago
8 votes 5 answers10k views
Does aspartimide formation dominate for tirzepatide held at 25 °C?

The case in front of me: aspartimide formation · tirzepatide · 25 °C. I want to know whether this is a real physical effect or an artefact of how it is measured. What…

peptide-stability
peptide-stability

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

832 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
hplc
hplc

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

466 questions
asked by u100_marks 38k · 9 months ago
8 votes5 answers9.6k views
Is 98.4% a realistic purity ceiling for cagrilintide given its chain length?

What I am working with: 98.4% · cagrilintide. The units are where I keep going wrong, so please be explicit about them. I have sanity-checked the order of magnitude…

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 triple_agonist_q 37k · 18 months ago
8 votes5 answers9.5k views
Why does hydrolysis accelerate at room temperature rather than proceeding linearly?

What I have: hydrolysis · room temperature. I can predict the outcome but I cannot explain it, which means I will get the next case wrong. I would like to know how…

peptide-stability
peptide-stability

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

832 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
hplc
hplc

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

466 questions
asked by cal_hennessy 14k · 8 months ago
8 votes5 answers7.9k views
Why does aspartimide formation accelerate at 2–8 °C rather than proceeding linearly?

Concretely: aspartimide formation · 2–8 °C. I want to know whether this is a real physical effect or an artefact of how it is measured. What prompted the question is…

peptide-stability
peptide-stability

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

832 questions
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
hplc
hplc

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

466 questions
asked by mz_4113 99k · 23 months ago
8 votes 4 answers5.7k views
Why does aspartimide formation accelerate at minus 20 °C rather than proceeding linearly?

Concretely: aspartimide formation · minus 20 °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
storage
storage

Storage conditions and their evidence base: minus twenty degrees for powder, refrigerated for solution, protection from light, and what the…

646 questions
hplc
hplc

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

466 questions
asked by wren_calloway 14k · 8 months ago