Quantitative Analysis of Residual Artificial Sweeteners in Surface Water by Highly Sensitive LC/MS/MS Method

Significance of the Topic

Artificial sweeteners are increasingly recognized as emerging contaminants in aquatic environments. Their widespread use in food and beverage industries leads to trace-level residues in surface waters and wastewaters, raising concerns about ecological and human health effects. Sensitive and direct analytical methods are essential for monitoring these compounds at ng/L levels without extensive sample preparation.

Objectives and Study Overview

This study describes the development and application of a highly sensitive LC/MS/MS method on a Shimadzu LCMS-8060 system for the direct quantitation of five common artificial sweeteners—acesulfame, cyclamate, saccharin, sucralose, and aspartame—in surface and drinking water. The goal was to achieve detection limits in the low ng/L range with rapid analysis and minimal sample handling.

Methodology

The method employs a fast gradient elution on a biphenyl UHPLC column coupled to a triple quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) mode. Key steps included:

• Preparation of mixed standard solutions from pure powder stocks, diluted to calibration levels between 1 and 1000 ng/L.
• Direct injection of 10 µL water samples (treated, reservoir, and spiked controls) without preconcentration.
• Use of optimized MRM transitions in both positive and negative electrospray modes, selected based on sensitivity and fragmentation characteristics.

Used Instrumentation

• Shimadzu LCMS-8060 triple quadrupole mass spectrometer with heated electrospray ionization.
• Shimadzu Nexera UHPLC system.
• Phenomenex Kinetex 2.6 µm Biphenyl column (100 mm × 2.1 mm).
• Gradient mobile phase: water (A) and methanol (B), 6-minute program at 0.3 mL/min.
• Nitrogen for nebulizing (3 L/min) and zero-air heating gas (20 L/min).

Main Results and Discussion

The method provided baseline separation of all five sweeteners within a 6-minute run. Calibration curves exhibited high linearity (R2 > 0.9968) over the ng/L range. Limits of detection were below 2.5 ng/L for four compounds and 30.6 ng/L for sucralose with 10 µL injection; sensitivity is expected to improve with larger injection volumes. Analysis of environmental samples revealed measurable levels of acesulfame, cyclamate, saccharin, and sucralose in treated and reservoir waters, while aspartame was often below the detection limit. The direct injection approach eliminated potential losses and contamination associated with pre-treatment.

Benefits and Practical Applications

The method’s rapid turnaround, minimal sample handling, and low detection limits make it well suited for routine environmental monitoring, industrial quality control, and regulatory compliance testing of artificial sweeteners in water. Its high throughput supports large-scale screening programs and real-time decision making in water treatment facilities.

Future Trends and Potential Applications

Advancements in UHPLC column technology and mass spectrometer interfaces are likely to further reduce analysis times and detection limits. Integration with online sample preconcentration or on-line solid-phase extraction could extend applicability to even lower concentration levels. Expanding the analyte panel to include new sweetener metabolites and transformation products will enhance comprehensive environmental risk assessments.

Conclusion

A robust, fast, and highly sensitive LC/MS/MS protocol was established for direct quantitation of key artificial sweeteners in surface and drinking waters. The approach delivers low ng/L detection capabilities without sample pre-treatment, facilitating accurate, high-throughput environmental monitoring.

Reference

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