A Sample Prep-Free Analysis of Saccharides Mixtures with “Smart IS+” and “SMCI+” - Authentication and Adulteration Studies -

Importance of the Topic

Saccharides play central roles as energy sources, structural biopolymers and metabolic markers. Conventional GC/MS analysis of sugars often demands time-consuming derivatization to protect hydroxyl groups before volatilization. A rapid, preparation-free approach enhances throughput in fields such as food authentication, quality control and metabolomics.

Objectives and Study Overview

This study evaluates two direct-inlet GC/MS configurations (“Smart IS+” and “SMCI+”) for qualitative saccharide analysis without derivatization. Key goals:

• Compare electron ionization (EI), quick chemical ionization (QCI) and solvent-mediated CI (SMCI) spectra of mono-, di- and oligosaccharides.
• Demonstrate temperature-resolved elution profiles for saccharide classification.
• Apply the method to authentication of manuka honey and detection of adulterants in table sugar.

Methodology and Instrumentation

Direct Sample Inlet (DI) probe coupled to a GCMS-TQ8050 NX system was used in two modes:

• Smart IS+: dual-source enabling rapid switch between EI and QCI (isobutane reagent gas).
• SMCI+: chemical ionization using methanol as reagent gas for safer, solvent-based PCI.

Samples (mono-, di-, oligosaccharides at 5000 ppm) were loaded into microvials on the DI probe. Thermal program: ramp at 20 °C/min to 100 °C, then 40 °C/min to 450 °C (7 min hold). Ion source at 230 °C. Mass scan range m/z 50–600 (scan speed 3333). MRM transitions were applied for targeted drug detection.

Main Results and Discussion

Temperature elution windows provided clear grouping:

• Mono­saccharides (rhamnose, ribose): 75–175 °C; glucose, fructose, galactose: 150–250 °C.
• Di-/oligosaccharides (maltose, lactose, sucrose, 1-kestose): 250–400 °C.

QCI and SMCI spectra showed nearly identical fragmentation patterns ([M-OH]+, [M-OH-H2O]+) with SMCI offering enhanced low-mass ion intensity. In mixtures, monosaccharides could be resolved from larger saccharides by elution temperature, though isomeric di-/oligosaccharides required ion-plot deconvolution.

Authentication example: natural manuka honey (only monosaccharides) vs honey spiked with sucrose exhibited an additional high-temperature peak. Adulteration test: sucrose spiked with trimethoprim, codeine, promethazine; EI and QCI enabled thermal separation of drug peaks (50–150 °C) and MRM confirmed identities (e.g. m/z 299 for codeine).

Benefits and Practical Applications

• Eliminates derivatization for rapid qualitative screening.
• Temperature-based grouping aids preliminary authentication of food and natural products.
• Dual-mode ionization and methanol-based CI improve safety and flexibility.
• MRM compatibility allows trace-level detection of adulterants.

Future Trends and Opportunities

• Extension to quantitative workflows and isotopic labeling studies.
• Integration with high-throughput automation platforms.
• Exploration of alternative reagent solvents for broader CI selectivity.
• Application to other polar metabolites and complex matrices.

Conclusion

Smart IS+ and SMCI+ configurations on a direct inlet GC/MS system offer a fast, derivatization-free route to saccharide profiling and preliminary authentication/adulteration screening. The approach combines flexible ionization modes, temperature-resolved elution and targeted MRM detection to meet the needs of food testing and metabolite analysis laboratories.