Home › Analytical Chem › Species Determination and Quantitation in Mixtures Using MRM Mass Spectrometry of Peptides Applied to Meat Authentication
Analytical Chem JoVE (Open Access) Citable · DOI

Species Determination and Quantitation in Mixtures Using MRM Mass Spectrometry of Peptides Applied to Meat Authentication

DOI: 10.3791/54420-v
What you'll learn
  • ✓ Apply MRM mass spectrometry to identify peptide signatures for species authentication
  • ✓ Quantify species composition in protein mixtures using peak area ratios
  • ✓ Detect adulterant species at 1% sensitivity in food fraud applications
Protocol

We present a protocol for identifying and quantifying the components in mixtures of species possessing similar proteins. Mass spectrometry detects peptides for identification, and gives relative quantitation by ratios of peak areas. As a tool food for fraud detection, the method can detect 1% horse in beef.

Difficulty
advanced
Total time
~4–6 hours per sample set (including proteolysis, calibration preparation, and analysis)

Steps

1
Perform proteolysis and analyze reference myoglobins

Digest reference myoglobin standards from different species using proteolytic enzymes to generate species-specific peptide fragments. Analyze the resulting peptides by MRM mass spectrometry to establish characteristic mass-to-charge signatures for each species.

▶ 00:54
2
Prepare and analyze calibration sample mixtures

Create calibration samples with known ratios of species (e.g., varying percentages of horse in beef). Digest these mixtures and analyze by MRM mass spectrometry to establish the relationship between peak area ratios and species composition percentages.

▶ 05:14
3
Interpret results for species mixture detection

Compare unknown sample peptide profiles and peak area ratios against the calibration curve to identify species components and quantify their relative abundance. Demonstrate sensitivity limits (e.g., detection of 1% horse adulterant in beef).

▶ 07:57
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