An improved quantification method for 12 linear dimethylsiloxanes and 1 cyclic dimethylsiloxane in...

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Polymer Science

Background:

• Polydimethylsiloxane (PDMS) 200 fluid is a common standard for quantifying linear dimethylsiloxanes (L5-L16) in environmental samples.
• Existing methods lack detailed quantification of individual dimethylsiloxanes within PDMS 200 fluid using gas chromatography-flame ionization detection (GC-FID).

Purpose of the Study:

• To develop and validate a precise GC-FID method for quantifying individual dimethylsiloxanes in PDMS 200 fluid.
• To address the limitations in current analytical protocols for siloxane analysis.

Main Methods:

• Identification of fifteen compounds, including D7, linear dimethylsiloxanes (L5-L16), and two unknowns in PDMS 200 fluid using gas chromatography-mass spectrometry (GC-MS).
• Determination of Retention Indices (RI) for linear dimethylsiloxanes L8-L16.
• Application of the effective carbon number (ECN) concept for dimethylsiloxane response factors in FID.
• Establishment and detailed description of a new quantification method based on GC-FID.

Main Results:

• Successful identification of 15 compounds in PDMS 200 fluid.
• First-time reporting of Retention Indices (RI) for L8-L16.
• Validation of the effective carbon number (ECN) concept for siloxane quantification.
• Demonstration that the new GC-FID method is more accurate and stable than external standard, internal standard, and normalization methods, especially for low-level D7 detection.

Conclusions:

• A novel and validated GC-FID quantification method for individual dimethylsiloxanes in PDMS 200 fluid has been developed.
• This method offers superior accuracy and stability compared to traditional approaches.
• The findings enhance the reliability of environmental monitoring of siloxanes.