Determination of Dimethyl-polysiloxanes (DMPS) in Edible Fats and Oils by ICP-OES

Significance of the Topic

Ensuring the safety and quality of edible fats and oils is critical for both manufacturers and consumers. Antifoaming agents such as dimethyl-polysiloxane (DMPS) are widely used to prevent foam formation during cooking and processing, but their levels must be controlled to meet regulatory limits and maintain product integrity.

Objectives and Study Overview

This application note presents a fast, stable, and robust method for the determination of DMPS in edible fats and oils using ICP-OES. Key objectives include:

• Developing a matrix-matched calibration protocol for fatty samples
• Evaluating detection limits, linearity, accuracy, and precision
• Assessing long-term stability and sample throughput

Methodology and Instrumentation

Instrument

• Agilent 5800 Radial View ICP-OES with 27 MHz solid-state RF and VistaChip III CCD detector
• Mixed argon–oxygen gas (80:20) to minimize carbon buildup
• Concentric nebulizer, double-pass glass cyclonic spray chamber, 1.4 mm i.d. injector torch

Sample and standards

• Soybean oil samples diluted in kerosene-based A-Solv solvent
• Calibration standards prepared at 0.2–10 mg/kg DMPS with matrix matching
• Yttrium internal standard (10 mg/kg) to correct for matrix effects

Operating conditions

• Read time: 5 s; replicates: 3; sample uptake delay: 10 s; stabilization time: 10 s
• RF power: 1.30 kW; plasma flow: 12.0 L/min; nebulizer flow: 0.6 L/min; oxygen injection: 20 %
• Pump speed: 12 rpm; fast pump: 80 rpm; viewing height: 8 mm

Main Results and Discussion

Key performance metrics

• Method detection limit (Si at 288.158 nm): 0.0329 mg/kg DMPS
• Linearity: correlation coefficient >0.99988 up to 10 mg/kg
• Spike recoveries: 105 % at 0.2 mg/kg and 101 % at 1.0 mg/kg
• Long-term precision: 2.1 % RSD over three hours at 0.2 mg/kg spike
• Throughput: 35 s per sample with total argon consumption <8.5 L/sample

Benefits and Practical Applications

• Rapid and reliable monitoring of antifoaming agents in food quality control
• High tolerance for organic matrices and elevated dissolved solids
• Reduced operating costs due to fast analysis and low gas consumption
• Minimal maintenance through vertical plasma design and SSRF stability

Future Trends and Opportunities

• Extension to multi-element profiling and simultaneous contaminant screening
• Integration with automated sample handling and advanced data analytics
• Development of portable or miniaturized plasma spectrometers for field testing
• Coupling with complementary techniques (e.g., GC-MS) for comprehensive oil characterization

Conclusion

The Agilent 5800 RV ICP-OES method provides a sensitive, accurate, and high-throughput approach for quantifying DMPS in edible oils. Its robust plasma design, excellent linearity, and low detection limits enable compliance with regulatory standards and support efficient quality control in food laboratories.

References

1. Food Additives: What is Dimethylpolysiloxane (E900) in Food and What are the Uses? FoodAdditives.net, December 2019.
2. Food and Agriculture Organization of the United Nations. Codex Standards for Fats and Oils Derived from Edible Fats and Oils, Section 4.
3. Food Safety and Standards Authority of India. Food Safety and Standards (Food Product Standards and Food Additives) Regulation, 2011, Chapter 3, Section 3.1.8.
4. Agilent Technologies. Resilient Vertical Torch Means Less Cleaning, Less Downtime, and Fewer Replacements—Even for Tough Samples. Publication 5994-1514EN.
5. Agilent Technologies. Fitted Background Correction (FBC)—Fast, accurate and fully automated background correction. Publication 5991-4836EN.