Tags · Technique
system suitability
The injections that establish whether a run was valid at all.
Related in this group: HPLC · LC-MS · high-resolution MS · MALDI-TOF · UV & DAD detection · peak integration · gradient method · water content · amino acid analysis · ELISA · endotoxin testing · sterility testing
47 topics · page 1 of 2
| Topic | Participants | Replies | Views | Activity |
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What a reversed-phase purity number actually is
The question in the title: What a reversed-phase purity number actually is I will give what I have already checked below so nobody repeats it. I would like to understand what this number means before I repeat…
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+87 | 101 | 27k | 4h |
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Repeatability versus intermediate precision — what changed since
Posting this under the heading it deserves: Repeatability versus intermediate precision — what changed since Everything below is what sits behind that. Working through the identity arithmetic and I would like…
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4 | 21k | 5h | |
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[2026 update] Detection wavelength and why 214 nm and 280 nm disagree
Detection wavelength and why 214 nm and 280 nm disagree — setting out what I have, and where I think it stops being reliable. Posting the method first, because I know what the first three replies will…
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+69 | 76 | 920 | 6h |
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Follow-up: Comparing two chromatograms from different laboratories, properly
Comparing two chromatograms from different laboratories, properly — setting out what I have, and where I think it stops being reliable. I would like to understand what this number means before I repeat it…
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+62 | 67 | 12k | 9h |
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Why 99.2% and 97.8% on the same lot can both be correct
Why 99.2% and 97.8% on the same lot can both be correct I have a specific reason for asking rather than idle curiosity, and the context is below. I would like to understand what this number means before I…
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+16 | 20 | 3.1k | 11h |
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Shoulders, tangent skims, and defensible integration
Posting this under the heading it deserves: Shoulders, tangent skims, and defensible integration Everything below is what sits behind that. Posting the method first, because I know what the first three…
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+16 | 20 | 11k | 13h |
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Revisiting: Spike-and-recover accuracy for a peptide assay
Revisiting: Spike-and-recover accuracy for a peptide assay — setting out what I have, and where I think it stops being reliable. I would like to understand what this number means before I repeat it anywhere.…
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2 | 6.8k | 21h | |
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Gradient steepness and apparent purity: a worked comparison — the long version
Gradient steepness and apparent purity: a worked comparison — the long version — setting out what I have, and where I think it stops being reliable. A documentation question rather than an analytical one. I…
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2 | 32k | 1d | |
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System suitability injections: if they failed, the run did not happen — the long version
System suitability injections: if they failed, the run did not happen — the long version — setting out what I have, and where I think it stops being reliable. A documentation question rather than an…
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+2 | 6 | 6.2k | 1d |
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Revisiting: Theoretical plates: useful number or ritual?
Asking directly, because I could not find a straight answer: Revisiting: Theoretical plates: useful number or ritual? I would like to understand what this number means before I repeat it anywhere. A…
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+16 | 21 | 1.2k | 1d |
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[2026 update] Why 99.2% and 97.8% on the same lot can both be correct
Why 99.2% and 97.8% on the same lot can both be correct — that is the question, and I have not found it answered plainly anywhere I have looked. I would like to understand what this number means before I…
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+1 | 5 | 719 | 2d |
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Coming back to: Specificity, linearity, accuracy, precision, range, robustness — with real criteria
On the subject in the title: Specificity, linearity, accuracy, precision, range, robustness — with real criteria Working notes rather than a conclusion. Posting the method first, because I know what the first…
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+93 | 99 | 1.4k | 6d |
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Carryover and the ghost peak from last week's standard — what changed since
Carryover and the ghost peak from last week's standard — what changed since Writing it up because I had to work it out twice and would rather nobody else did. Posting the method first, because I know what the…
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+98 | 114 | 37k | 22d |
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Resolution and tailing factor: real acceptance criteria
Resolution and tailing factor: real acceptance criteria Writing it up because I had to work it out twice and would rather nobody else did. I would like to understand what this number means before I repeat it…
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2 | 15k | 1mo | |
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Injection volume, overload, and peak distortion
Posting this under the heading it deserves: Injection volume, overload, and peak distortion Everything below is what sits behind that. A documentation question rather than an analytical one. I have a…
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+43 | 47 | 36k | 2mo |
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Area percent versus weight percent: the confusion that causes most arguments
Posting this under the heading it deserves: Area percent versus weight percent: the confusion that causes most arguments Everything below is what sits behind that. Posting the method first, because I know…
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+10 | 14 | 2.1k | 2mo |
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Validating a method you did not develop
On the subject in the title: Validating a method you did not develop Working notes rather than a conclusion. I would like to understand what this number means before I repeat it anywhere. A VendorInvestigate…
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+10 | 14 | 15k | 3mo |
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Sample handling between despatch and injection
Sample handling between despatch and injection Writing it up because I had to work it out twice and would rather nobody else did. Posting the method first, because I know what the first three replies will…
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+63 | 68 | 2.4k | 3mo |
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Second pass at: Robustness: the parameters worth deliberately varying
On the subject in the title: Second pass at: Robustness: the parameters worth deliberately varying Working notes rather than a conclusion. I would like to understand what this number means before I repeat it…
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+61 | 66 | 9.5k | 3mo |
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Shoulders, tangent skims, and defensible integration — the long version
Shoulders, tangent skims, and defensible integration — the long version Writing it up because I had to work it out twice and would rather nobody else did. Posting the method first, because I know what the…
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+16 | 20 | 27k | 3mo |
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Spike-and-recover accuracy for a peptide assay
Posting this under the heading it deserves: Spike-and-recover accuracy for a peptide assay Everything below is what sits behind that. A documentation question rather than an analytical one. I have a…
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+121 | 126 | 1.5k | 4mo |
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Injection volume, overload, and peak distortion — one year on
Injection volume, overload, and peak distortion — one year on Writing it up because I had to work it out twice and would rather nobody else did. A documentation question rather than an analytical one. I have…
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+4 | 8 | 1.2k | 4mo |
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Why one laboratory's 98.4% and another's 96.1% may not contradict — one year on
Asking directly, because I could not find a straight answer: Why one laboratory's 98.4% and another's 96.1% may not contradict — one year on Working through the identity arithmetic and I would like it…
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+10 | 14 | 13k | 5mo |
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Revisiting: Sample handling between despatch and injection
Posting this under the heading it deserves: Revisiting: Sample handling between despatch and injection Everything below is what sits behind that. Posting the method first, because I know what the first three…
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+5 | 9 | 1.1k | 6mo |
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An inter-laboratory comparison on one lot, tabulated — what changed since
An inter-laboratory comparison on one lot, tabulated — what changed since — setting out what I have, and where I think it stops being reliable. I would like to understand what this number means before I…
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+24 | 28 | 3.3k | 7mo |
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Comparing two chromatograms from different laboratories, properly
Posting this under the heading it deserves: Comparing two chromatograms from different laboratories, properly Everything below is what sits behind that. I would like to understand what this number means…
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+35 | 40 | 22k | 7mo |
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Where the integrator drew the baseline, and how much it moved the number
Where the integrator drew the baseline, and how much it moved the number — setting out what I have, and where I think it stops being reliable. Posting the method first, because I know what the first three…
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+20 | 24 | 1.6k | 8mo |
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What a reversed-phase purity number actually is — the long version
What a reversed-phase purity number actually is — the long version I have a specific reason for asking rather than idle curiosity, and the context is below. I would like to understand what this number means…
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2 | 15k | 8mo | |
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LOD and LOQ: definitions people get wrong
LOD and LOQ: definitions people get wrong — setting out what I have, and where I think it stops being reliable. A documentation question rather than an analytical one. I have a certificate in front of me that…
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2 | 43k | 8mo | |
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Detection wavelength and why 214 nm and 280 nm disagree
On the subject in the title: Detection wavelength and why 214 nm and 280 nm disagree Working notes rather than a conclusion. Posting the method first, because I know what the first three replies will…
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+78 | 84 | 1.7k | 8mo |