Support technique
by Application Area

Follow the product datasheet for buffer and concentration. Add buffer gently, allow the vial to stand, then mix without vigorous vortexing. Prepare single-use aliquots in low-binding tubes and avoid repeated freeze-thaw cycles.

Review storage temperature, buffer composition, concentration and freeze-thaw history. Aggregation may occur after vigorous mixing, prolonged room-temperature exposure or storage near the isoelectric point. Compare a fresh aliquot and use an appropriate positive-control assay.

Use the product datasheet because suitable pH, ionic strength, cofactors, reducing agents and carrier proteins depend on the molecule and assay. If a buffer exchange is required, test a small aliquot first and avoid conditions near the protein's isoelectric point when aggregation is a concern.

For a purified protein, A280 can be used when the sequence-based extinction coefficient and path length are known. A compatible colorimetric assay can be used when excipients interfere with absorbance. Measure against the correct blank and avoid assuming that total protein concentration equals active protein concentration.

Include a reagent blank, vehicle control, known active positive control and a concentration series of the test protein. Keep buffer composition and incubation conditions matched. For enzymes, confirm that substrate conversion is measured within the initial linear range.

Les causes les plus fréquentes de l'absence de bande sont :

• Échec de l'amorce — vérifier la température de fusion (Tm), la teneur en GC (40-60 %) et s'assurer que les amorces ne forment pas de dimères
• Matrice dégradée — faire migrer la matrice sur gel pour en confirmer l'intégrité ; le rapport A260/A280 doit être de 1,8-2,0
• Inhibiteurs dans la matrice — la présence d'éthanol, de phénol ou d'EDTA peut bloquer la polymérase
• Concentration de Mg²⁺ incorrecte — la concentration standard est de 1,5 mM ; titrer entre 1,0 et 3,0 mM
• Température d'hybridation trop élevée — essayer de la réduire par paliers de 5 °C

Pour la plupart des analyses qPCR, 1 à 10 ng d'ADNc ou d'ADN génomique par réaction de 20 µL sont optimaux. Une surcharge (> 100 ng) provoque une inhibition et des valeurs Cq artificiellement élevées. Une sous-charge (< 0,01 ng) augmente la variabilité inter-réplicats.

Exécutez toujours une courbe standard sur 4 à 5 dilutions log pour vérifier l'efficacité de la réaction (90 à 110 % acceptable). L'efficacité est calculée comme suit : E = (10^(–1/pente)) – 1.

Check template integrity and purity, reverse-transcription consistency, pipetting, primer specificity and reaction efficiency. Run a standard curve, no-template control and no-reverse-transcriptase control where relevant. Replicate variability often increases close to the assay's limit of quantification.

Early amplification with a product-like melt peak may indicate contamination. Late amplification with a lower melt temperature often suggests primer-dimer formation, but confirm by melt analysis or gel electrophoresis. Replace suspect reagents and keep pre-amplification work physically separate from amplified products.

Prepare standards with calibrated pipettes, mix every dilution thoroughly and run duplicates. Confirm the correct curve model for the kit, subtract blanks as instructed and avoid using readings outside the plate reader’s linear range.

High CV commonly results from inconsistent pipetting, bubbles, incomplete mixing, edge effects or unequal incubation times. Use a multichannel pipette consistently, remove bubbles before reading and add reagents in the same sequence across the plate.

Un signal faible indique généralement l'une des causes suivantes :

• Péremption du réactif ou dommages dus à la congélation/décongélation — vérifiez les dates de lot ; évitez les congélations/décongélations répétées des anticorps
• Temps ou température d'incubation insuffisants — assurez-vous que la plaque est à la bonne température et que l'incubation n'est pas interrompue prématurément
• Substrat non activé — le substrat TMB doit être à température ambiante avant utilisation
• Concentration de l'échantillon trop faible — assurez-vous que l'échantillon se situe dans la plage de la courbe étalon ; concentrez si nécessaire

Check wash performance, reagent dilution, incubation time, substrate development time and plate drying. Confirm that the conjugate and substrate were prepared correctly and that the plate reader wavelength is appropriate. Repeat with fresh wash buffer and include blank wells to identify reagent background.

Do not extrapolate beyond the validated standard range. Dilute samples above the range and repeat them, then apply the dilution factor. Samples below the lower limit should be reported according to the kit's validated detection and quantification limits rather than assigned an unsupported concentration.

Le mycoplasme est le contaminant de culture cellulaire le plus répandu et est invisible à l'œil nu ou à la microscopie optique standard. Méthodes de détection :

• Détection par PCR — la plus sensible ; le kit de détection de mycoplasmes ABMIUM (réf. AB-MYC-01) détecte plus de 90 espèces
• Coloration DAPI/Hoechst — les mycoplasmes apparaissent comme de petits points fluorescents autour des noyaux

Pour l'élimination, un traitement au BM-Cyclin sur deux cycles de 7 jours est efficace pour la plupart des souches. Confirmer l'élimination 2 semaines après le traitement.

Check the product-specific shipping and stability statement before use. Photograph the parcel, record the arrival temperature and contact support with the catalogue number, lot number and delivery date. Do not discard packaging until the case is reviewed.

Provide catalogue and lot numbers, order reference, storage history, protocol, sample type, controls, instrument settings and representative raw data or images. Include the expected result and the observed result.

Stop before using the kit, retain the packaging and photograph the shipment. Record the product, lot, order number and affected component, then contact support. Do not combine components from different lots unless the instructions explicitly allow it.

Check the product-specific instructions before use. Some salts or concentrated buffers can precipitate during cold storage and may redissolve under specified conditions, while unexpected precipitate can indicate contamination or degradation. Do not heat, filter or discard material unless the instructions permit it.

Performance after the stated expiry date is not assured. Use an in-date product for regulated, diagnostic or decision-critical work. For exploratory research, any use beyond expiry should be qualified against an in-date control and documented, but support specifications may no longer apply.