Simple Screening Analysis of Detergent Using a Single Quadrupole Mass Spectrometer

Significance of the Topic

Detergents contain a variety of surfactants and stabilizers that influence cleaning performance and skin compatibility. Rapid screening of these components is critical in product development, quality control and foreign matter inspection, especially when residues may contaminate food or beverages.

Objectives and Study Overview

This study demonstrates a simple, high-throughput screening method for commercial dishwashing detergents using flow injection analysis coupled with a single quadrupole LC-MS. Multivariate analysis of mass spectral data enables classification of detergent formulations and identification of characteristic compounds.

Methodology and Sample Preparation

Seven commercial dishwashing detergents were diluted 1000-fold in 70 % aqueous methanol. Reserpine and chloramphenicol were added at 30 ppm as internal standards. Samples were directly injected by flow injection without a separation column, achieving a cycle time of 1 minute per sample.

Used Instrumentation

• Nexera XR system with flow injection capability (flow rate program from 0.1 to 1 mL/min; mobile phase water/methanol 30:70; injection volume 1 μL)
• LCMS-2050 single quadrupole mass spectrometer (DUIS ESI/APCI ionization; positive and negative scan mode m/z 50–2000; interface voltage +3.0 kV/-2.0 kV; gas flows and temperatures per manufacturer)
• LabSolutions software for data conversion to JCAMP format
• eMSTAT Solution for multivariate statistical and discriminant analysis

Major Results and Discussion

Positive-mode analysis detected 263 peaks (up to m/z 1390.49) and negative-mode analysis detected 171 peaks (up to m/z 802.36). Principal component analysis (PCA) of positive-mode spectra separated detergents A–D from E–G along the first component and further distinguished A–D along the second component.

Key characteristic peaks included:

• m/z 163.28 assigned to butyl carbitol in detergent A
• m/z 230.32 assigned to C12 alkylamine oxide in detergents B–D
• Recurring peaks at 44 Da intervals (e.g., m/z 649.53, 693.48, 737.51, 781.52) in detergent G, indicating polyoxyethylene alkyl ether nonionic surfactants

Benefits and Practical Applications

This flow injection LC-MS approach delivers high throughput (1 min per sample) without column maintenance concerns. Multivariate analysis streamlines sample classification and marker detection, supporting rapid formulation screening in research and quality labs as well as foreign matter examination.

Future Trends and Applications

Advances may include integration with high-resolution mass spectrometry for enhanced compound identification, real-time monitoring of detergent residues, and miniaturized or portable MS platforms for in-field or on-line process control. Expanded chemometric workflows can further automate classification across broader product families.

Conclusion

The single quadrupole LC-MS method with flow injection and eMSTAT multivariate analysis offers a fast, robust and user-friendly screening tool for detergent component profiling. It enables clear sample classification and identification of signature compounds in under one minute per analysis.

References

1. Analysis of Contaminated Samples by DPiMS-2020 (1): Detection of Surfactants in Beverages Application News No.B118