ペプチド分析サービス

生物学研究および産業用途を目的としており、個人の臨床用途または医療用途を意図したものではありません。

同一性、純度、バッチ間の一貫性の確認、および開発上の意思決定を支える分析キャラクタリゼーション。

プロジェクト相談

目的配列、純度、スケール、修飾、納品形態、必要書類をお知らせください。Quantai が実現性を確認し、実務的な見積ルートをご提案します。

中核技術

HPLC/UPLC による純度評価

Purity is measured by reversed-phase separation and reported as the area of the main peak against the total peak area at a stated wavelength. Two details decide whether that number means anything. The gradient has to actually resolve the impurities the process produces, since anything co-eluting with the main peak is counted as product. And the detection wavelength matters, because 214 nm sees the amide backbone of every peptide fragment while 280 nm sees only aromatic residues. A purity figure without its chromatogram and conditions is not verifiable.

LC-MS および MALDI-TOF による確認

Mass spectrometry answers whether the material is the intended sequence. Electrospray ionisation coupled to liquid chromatography gives mass alongside the separation, so each peak in the chromatogram can be assigned rather than guessed at. MALDI-TOF is faster for a straight identity check and tolerates salts better, which makes it useful for screening many samples. Neither distinguishes sequences of identical composition on mass alone, so an isomeric substitution needs fragmentation data.

アミノ酸組成と不純物の評価

技術範囲、品質レベル、バッチ文書、納品要件はプロジェクトの段階に応じて設定できます。

バッチ文書と分析法サポート

技術範囲、品質レベル、バッチ文書、納品要件はプロジェクトの段階に応じて設定できます。

標準的な流れ

1要件確認

2技術的実現性

3見積とスケジュール

4合成またはプロセス実行

5QC 文書

6出荷とフォローアップ

開発段階	ペプチドサポート
コンセプトと実現性	ペプチド設計戦略、配列最適化、実現性評価
探索研究	カスタムペプチド合成、ターゲティングペプチド設計、機能スクリーニング支援
リード最適化	ペプチド修飾、コンジュゲーション戦略、構造活性最適化
プロセス開発	合成ルート最適化、プロセス頑健性、不純物管理戦略
GMP 製造	GMP 準拠のペプチド合成、品質文書、バッチ出荷判定の支援

技術ノート

Purity, content and the difference between them

These two numbers are routinely confused and they are not interchangeable. HPLC purity says what fraction of the peptide-related material is the target. Peptide content says what fraction of the powder in the vial is peptide at all, with the remainder being counter-ion, water and residual salts. A peptide can be 98 percent pure and still be only 80 percent of the delivered mass. Where a concentration has to be accurate, content is the number that matters, and it is determined by amino acid analysis or nitrogen determination rather than by HPLC.

Water content and residual solvents

Lyophilised peptides are hygroscopic, and water is often the largest non-peptide component. Karl Fischer titration measures it specifically, unlike loss on drying which also captures anything else volatile. Residual solvents from synthesis and purification, typically acetonitrile and the amide solvents used for coupling, are measured by headspace gas chromatography against the limits for their class.

Counter-ion determination

Whatever acid was in the purification mobile phase leaves with the peptide as its counter-ion. Trifluoroacetate is measured by ion chromatography or by fluorine-19 NMR; acetate by ion chromatography or capillary electrophoresis. This matters beyond bookkeeping: residual TFA has measurable effects in some cell assays, and the counter-ion contributes directly to the mass of powder weighed out for a given peptide quantity.

Impurity profiling

The impurities in a synthetic peptide are largely predictable from how it was made. Deletion sequences arise from incomplete couplings, truncated sequences from capped chains, and oxidation and deamidation from susceptible residues under process or storage conditions. Identifying the significant peaks rather than only counting them is what makes a purity number actionable, because a related substance that co-elutes today may separate under a different gradient tomorrow and change the reported figure.

Biological and safety testing

Where material contacts biological systems, additional parameters apply: bacterial endotoxin by the LAL assay, bioburden, and sterility where the product is presented as sterile. These are separate determinations with their own methods and acceptance criteria, and whether they belong on a specification depends on the intended use rather than on the peptide itself.

納品物

Analytical report with results, method conditions and acceptance criteria
Chromatograms and spectra as acquired, not only the derived numbers
System suitability data demonstrating instrument performance
Method description sufficient to reproduce the analysis
Assignment of significant impurity peaks where impurity profiling is in scope

主な用途

Incoming material verification — Independent confirmation of identity, purity and content for peptide received from another supplier, before it is committed to a study.

Stability monitoring — Repeat analysis at defined intervals and storage conditions, tracking the parameters that move first for the sequence in question.

Investigating an unexpected result — Impurity profiling and identity work where an assay result does not match expectation and the material itself is a candidate explanation.

Specification development — Characterising what a process actually produces, so that acceptance criteria are set against reality rather than against a template.

よくあるご質問

Why does my peptide weigh more than the peptide I ordered?

Because the powder is not all peptide. Counter-ion, bound water and residual salts make up the rest, and together they commonly account for a substantial fraction of the mass. Peptide content quantifies this. If you are preparing solutions at a defined concentration, calculate from content rather than from gross weight.

Which wavelength should purity be reported at?

214 nm is the usual choice because the peptide bond absorbs there, so every peptide-related species is detected regardless of composition. 280 nm only sees tryptophan, tyrosine and cystine, which means it can miss impurities entirely and give a flatteringly high number. Whichever is used, it should be stated with the result.

Can mass spectrometry confirm the sequence?

Mass alone confirms composition, not order. Two sequences with the same residues in a different order have the same mass. Tandem mass spectrometry fragments the peptide and reads the order from fragment mass differences, and that is what is needed when the sequence itself is in question.

Do you analyse peptides you did not synthesise?

Yes. Independent verification of third-party material is a common request, particularly before committing a batch to a long study. Send what you have on the expected sequence and modifications, since the method has to be set up against what the material is supposed to be.

What is system suitability and why is it in the report?

It is a set of checks run alongside the samples to show the instrument and method were performing within limits during that specific run, covering aspects such as peak resolution, repeatability and tailing. Without it, a result is a number with no evidence that the measurement was working when it was taken.

How much material does analysis need?

It depends on which determinations are in scope. Identity and purity by HPLC-MS need very little. Amino acid analysis, water content, residual solvents and counter-ion determination each consume sample separately, so a full characterisation panel needs meaningfully more than a purity check. Tell us the panel and we will state the quantity.