Both, MALDI-TOF spectrometers and HPLC analysis are routinely used to check the quality of our oligonucleotides.
1) MALDI-TOF mass spectrometry
MALDI-TOF (Matrix Assisted Laser Desorption/Ionization – Time Of Flight) is an analytical method based on laser ionisation of the analyte (oligonucleotide) molecule with the support of the matrix material. Excitation is followed by determining the time needed by the ionised molecule to “fly” along an evacuated tube towards a detector. Mass spectrum analysis allows very accurate comparison of predicted and real molecular mass and also recognition of respective impurities. This enables highly reliable quality assessment of a synthetized sequence.
MALDI-TOF analysis is routinely performed in a representative sample of oligonucleotides from every synthesis run and also in all oligonucleotides at risk of lower quality (e. g. in modified oligos). The customer is not informed of these analyses.
2) HPLC analysis
HPLC analysis oligonucleotide quality is assessed based on the magnitude of the negative charge of its molecule. The resultant chromatogram reveals the presence of respective incomplete chains and other unwanted synthesis products. In case of labelled or otherwise modified oligos, the chromatogram reveals the presence of unlabelled chains.
HPLC quality control is available subject to a surcharge of 10 € (excluding VAT). Customers receive a chromatogram record with a description of peaks together with the oligonucleotides. Each oligo ordered with HPLC quality control is surcharged with additional fee 10€ regardless delivery term, labelling or other modifications.
HPLC quality control is automatically performed without any surcharge when HPLC oligo purification is ordered.