Rapid elucidation of carotenoids in microalgae formulations by MRMS aXelerate

Importance of the Topic

Microalgae such as Arthrospira platensis (Spirulina) are valued for their rich content of bioactive pigments, especially carotenoids, which exhibit antioxidant, anti-aging and health-promoting effects. Accurate and rapid profiling of these pigments is essential for quality control in nutraceutical and pharmaceutical industries and for deepening our understanding of microalgae metabolomics.

Objectives and Study Overview

This work aimed to establish a direct infusion APCI–Magnetic Resonance Mass Spectrometry (DI-APCI-MRMS) approach for the qualitative and quantitative analysis of Spirulina pigment fractions in three commercial dietary supplements. The goal was to achieve ultra-high mass resolution and sub-ppm mass accuracy within a minimal analysis time.

Methodology and Instrumentation

Pigments were extracted from Spirulina powders and tablets using repeated ethanol extractions fortified with BHT, followed by ultrasonic treatment, stirring, centrifugation and lyophilization. Analysis was performed on a solariX XR 7 T MRMS equipped with an Apollo II APCI ion source. Samples (10 µg/mL in methanol) were infused at 50 µL/min. Spectra were acquired in broadband mode (150–3000 m/z) with an 8 M transient, providing 700,000 resolving power at m/z 400. Calibration used sodium trifluoroacetate, and data processing (feature extraction, alignment and database search) was carried out in MetaboScape 4.0.

Main Results and Discussion

The DI-APCI-MRMS platform enabled tentative detection of 49 pigment-related compounds, including carotenes, xanthophylls, chlorophylls and their derivatives, in under 4 minutes per sample. The method achieved mass accuracy better than 0.1 ppm and facilitated confident compound assignments, corroborated by isotopic fine structure analysis (e.g., Pyro Chlorophyllide-a). APCI ionization outperformed electrospray for most analyte classes, demonstrating suitability for complex phytochemical matrices.

Benefits and Practical Applications

This workflow offers:

• High-throughput screening capability for Spirulina product quality control
• Superior resolution and accuracy to resolve isobaric pigments without chromatographic separation
• Comprehensive profiling essential for nutraceutical standardization and regulatory compliance

Future Trends and Applications

Prospective developments include integration of quantitative MRMS workflows, minimal chromatographic front-ends for targeted assays, application to diverse microalgae species, and incorporation of machine-learning-based spectral libraries for automated identification. Such advances could solidify MRMS as a core technique in industrial QC and research metabolomics.

Conclusion

The DI-APCI-MRMS strategy delivers rapid, accurate and in-depth profiling of carotenoids and chlorophylls in Spirulina formulations. Its adoption promises to enhance product quality assurance, reveal novel bioactive pigments and advance analytical capabilities in the microalgae field.

References

• Singh S, Kate BN, Banerjee UC (2005) Bioactive Compounds from Cyanobacteria and Microalgae: An Overview. Crit Rev Biotechnol 25:73–95
• Mendiola JA et al. (2005) Characterization via LC-DAD-MS/MS of supercritical fluid antioxidant extracts of Spirulina platensis. J Sep Sci 28:1031–1038
• Hynstova V et al. (2018) Separation and quantification of carotenoids and chlorophylls in dietary supplements containing Chlorella vulgaris and Spirulina platensis using HPTLC. J Pharm Biomed Anal 148:108–118