Servicios de análisis de péptidos

Consulta en línea

Diseñado para investigación biológica y aplicaciones industriales; no destinado a fines clínicos o médicos individuales.

Caracterización analítica de identidad, pureza, uniformidad entre lotes y toma de decisiones de desarrollo.

Discusión del proyecto

Comparta su secuencia objetivo, pureza, escala, modificación, formato de entrega y requisitos de documentación. Quantai evaluará la viabilidad y responderá con una vía de cotización práctica.

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Capacidades principales

Evaluación de pureza por HPLC/UPLC

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.

Confirmación por LC-MS y MALDI-TOF

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.

Composición de aminoácidos y revisión de impurezas

El alcance técnico, el nivel de calidad, los documentos de lote y los requisitos de entrega se configuran según la etapa del proyecto.

Documentación de lote y soporte de métodos

El alcance técnico, el nivel de calidad, los documentos de lote y los requisitos de entrega se configuran según la etapa del proyecto.

Flujo de trabajo típico

1Revisión de requisitos

2Viabilidad técnica

3Cotización y cronograma

4Síntesis o ejecución del proceso

5Documentación de QC

6Envío y seguimiento

Etapa de desarrollo	Nuestro soporte en péptidos
Concepto y viabilidad	Estrategia de diseño peptídico, optimización de secuencia y evaluación de viabilidad
Investigación de descubrimiento	Síntesis peptídica a medida, diseño de péptidos de direccionamiento y apoyo al cribado funcional
Optimización de cabeza de serie	Modificación peptídica, estrategia de conjugación y optimización estructura-función
Desarrollo de procesos	Optimización de ruta, robustez del proceso y estrategia de control de impurezas
Fabricación GMP	Síntesis peptídica conforme a GMP, documentación de calidad y apoyo a la liberación de lotes

Notas técnicas

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.

Qué recibe

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

Aplicaciones habituales

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.

Preguntas frecuentes

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.

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