Frequently Asked Questions (FAQs)

1. What type of sample can be analyzed?

Essentially, any compound that can be ionized and subsequently fragmented can be used for MRM analysis. This includes proteins and peptides, metabolites, or drugs in complex mixtures (such as plasma and serum). Proteins can be quantified via MRM analysis of their corresponding digested peptides. MRM is particularly suited for detecting and quantifying biomarkers, allowing multiple MRMs to be monitored in a single experiment.

2. What is the maximum sample volume?

The sample volume should be less than 250 µL.

3. How sensitive is MRM?

MRM is a highly sensitive technique. Peptides can be accurately quantified at the femtomole level. In complex samples such as plasma, peptides can be measured at the µg/ml level.

4. Is MRM compatible with absolute or relative quantification?

MRM can deliver results for both absolute and relative quantification. While relative quantification is simpler, absolute quantification requires the use of appropriate standards. For absolute quantification, specific peptides are quantified against a spiked internal standard (e.g., synthetically labeled stable isotope peptide standard) to generate a protein concentration measurement.

5. Is method development required?

Yes, each project requires method development tailored to its specific needs. MRM analysis, particularly for complex mixtures, samples may need to be cleaned up by substantial chromatographic separation or additional sample preparation, which may require and incur additional charges.

6. Is it important that the proteome you are examining is present in an existing database?

Yes, proteome mapping is most effective when the genome is already known. If the genome is partially known, results will be limited. However, advanced de novo sequencing techniques can be applied to address such challenges.