Quantitative Determination of Octamethylcyclotetrasiloxane (D<sub>4</sub>) in Extracts of Biological Matrices by Gas Chromatography-Mass Spectrometry

Varaprath, Sudarsanan; Seaton, Mark J.; McNett, Debra A.; Cao, Lin; Plotzke, Kathleen P.

doi:10.1080/03067310008032683

Cited by 36 publications

(25 citation statements)

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“…It is also known that bleed signals consisting predominantly of the cyclic siloxanes D 3 and D 4 arise from polysiloxane based stationary phases as a result of thermal and/or oxidative degradation [152]. Background levels of D 4 observed in GC-MS when using a siloxane-based stationary phase can also be attributed to the presence of water in the sample [153]. This was illustrated ( Figure 5) by a comparison of a series of chromatograms from 1) no injection (a dry run), 2) analysis of reagent grade THF as purchased (slightly wet) and 3) analysis of the same THF to which 10% water was deliberately added.…”

Section: Background Levels Pertaining To Octamethylcyclotetrasiloxanementioning

confidence: 98%

A Primer on the Analytical Aspects of Silicones at Trace Levels-Challenges and Artifacts – A Review

2006

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Silicones (polydimethylsiloxanes) find use in a wide variety of industrial and consumer product applications because of their outstanding properties. Potential human exposure to silicones occurs in the work place during manufacturing and product formulation, as well as through the normal use of consumer products containing them.The entry of silicones into various environmental compartments raised health and safety concerns from potential exposure and mandated numerous environmental and toxicological studies. Such studies require qualitative and quantitative determination of silicone species at trace levels. However, the ubiquitous presence of silicones coupled with their unique chemistry renders their analysis at trace levels challenging.This paper provides a consolidated account of various aspects of silicones that must be borne in mind to obtain reliable data. The following topics are discussed: differences in the chemistry of silicones vs carbon; precautions in sample handling to avoid losses and inadvertent chemical transformation; potential sources for artifacts and interferences that could lead to systematic errors and data misinterpretation; sources for background and the need for matrix matched blank experiments; distinguishing silicones from silicates to avoid overestimation; potential for incorrect structural assignments; preventing inadvertent contamination; and questionable claims on the presence of silicones in biological matrices including that of silicone implants.

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Section: Background Levels Pertaining To Octamethylcyclotetrasiloxanementioning

confidence: 98%

A Primer on the Analytical Aspects of Silicones at Trace Levels-Challenges and Artifacts – A Review

2006

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“…In general GC atomic emission spectroscopy (element‐specific monitoring of silicon) and GC‐MS have been used for VMS analysis because the analytes are thermally stable and volatile. There are major analytical challenges related to laboratory contamination because of the wide use of silicone based products (including GC septa and MS pump oils) and generation of cyclic siloxanes from PDMS‐based GC stationary phases (Varaprath et al 2000, 2006). As a result many environmental and human measurements of cyclic siloxanes are suspect due to possible inadvertent contamination during sampling or analysis because of the use of silicone‐based materials in lubricants and consumer products.…”

Section: Guidelines For Using New Measurements To Demonstrate Exposurmentioning

confidence: 99%

Use of Measurement Data in Evaluating Exposure of Humans and Wildlife to POPs/PBTs

Swackhamer

Needham

Powell

et al. 2009

Integr Envir Assess & Manag

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The Stockholm Convention on Persistent Organic Pollutants (POPs) recognized that POPs resist degradation, undergo long-range transport, and accumulate in remote ecosystems. The Stockholm Convention also acknowledged that indigenous communities, particularly in the Arctic, were at risk because of the biomagnification of POPs and contamination of their traditional foods. This recognition was largely based on environmental monitoring data and demonstrates the need to have adequate guidance on data collection and use. Although long-range transport, persistence, and bioaccumulation models are important for screening potential POPs and for assessing human exposure, environmental measurement data are needed to confirm predictions. Indeed the Stockholm Convention (Annex E) requires monitoring data for assessing "exposure in local areas and, in particular, as a result of long-range environmental transport". However, there is relatively little guidance available on the most appropriate environmental measurement approaches, particularly for new candidate POPs, and on how to create a weight of evidence based on such data. We provide guidance on how to assess existing data that have been generated by monitoring programs and individual studies on the exposure of top predators and humans to candidate or potential POPs, as well as considerations for collecting new additional data. Our overall recommendation for assessing exposure in humans and top predators is to use or obtain direct measurements of the compound of concern from a significantly and uniquely exposed population (indigenous populations, remote populations), as well as data demonstrating biomagnification within food webs and time trends if possible. These data must be from the appropriate sample matrix type, collected and analyzed using accepted methodologies, reviewed for quality assurance, and interpreted correctly in order to be used to assess exposure.

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“…Similarly, Gasking (1988) reports that the breakdown of septa used in gas chromatography could be a source of silicone oligomers. Furthermore, Varaprath et al (2000) conclude that PDMS-based gas chromatography stationary phases could generate D4 through reaction with water present in extracts if they are not thoroughly dried prior to injection onto the column; similar effects are reported by Knobloch and Engewald (1995). In a recent poster presentation, Varaprath et al (2005) highlighted the analytical problems that may be encountered when silicones are analysed.…”

Section: Environmental Concentrationsmentioning

confidence: 74%

Temperature Dependence of the Organic Carbon/Water Partition Ratios (K_OC) of Volatile Methylsiloxanes

Panagopoulos

Jahnke

Kierkegaard

et al. 2017

Environ. Sci. Technol. Lett.

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Knowing the temperature dependence of the organic carbon/water partition ratios (K OC ) of volatile methylsiloxanes (VMS) is required to understand their environmental fate. We measured the K OC of two linear VMS (lVMS), three cyclic VMS (cVMS), and six polychlorinated biphenyls (PCBs) at 25, 15, 10, and 5 °C and calculated their enthalpies and entropies of sorption to organic carbon (ΔH OC and ΔS OC , respectively). The ΔH OC of VMS ranged from −79.2 to −45.8 kJ mol −1 , while the ΔH OC of the PCBs ranged from −68.7 to −29.3 kJ mol −1 . Previously reported measurements of the enthalpy of phase change between octanol and water (ΔH OW ) for cVMS (11.3−68.8 kJ mol −1 ) differed substantially from our ΔH OC measurements, even showing different signs (negative versus positive). Literature data of ΔH OC and ΔH OW for PCBs (−61 to −17 kJ mol −1 ) are closer to our measured values of ΔH OC for the PCBs showing the same sign (negative) with differences within a factor of 2 in the majority of the cases. Comparison of all available data for PCBs and VMS indicated that there may be important differences between ΔH OC and ΔH OW , especially for the VMS. Therefore, assuming ΔH OC equals ΔH OW in environmental fate models may be a source of substantial error.

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Quantitative Determination of Octamethylcyclotetrasiloxane (D₄) in Extracts of Biological Matrices by Gas Chromatography-Mass Spectrometry

Cited by 36 publications

References 11 publications

A Primer on the Analytical Aspects of Silicones at Trace Levels-Challenges and Artifacts – A Review

A Primer on the Analytical Aspects of Silicones at Trace Levels-Challenges and Artifacts – A Review

Use of Measurement Data in Evaluating Exposure of Humans and Wildlife to POPs/PBTs

Temperature Dependence of the Organic Carbon/Water Partition Ratios (K_OC) of Volatile Methylsiloxanes

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Quantitative Determination of Octamethylcyclotetrasiloxane (D4) in Extracts of Biological Matrices by Gas Chromatography-Mass Spectrometry

Cited by 36 publications

References 11 publications

A Primer on the Analytical Aspects of Silicones at Trace Levels-Challenges and Artifacts – A Review

A Primer on the Analytical Aspects of Silicones at Trace Levels-Challenges and Artifacts – A Review

Use of Measurement Data in Evaluating Exposure of Humans and Wildlife to POPs/PBTs

Temperature Dependence of the Organic Carbon/Water Partition Ratios (KOC) of Volatile Methylsiloxanes

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Quantitative Determination of Octamethylcyclotetrasiloxane (D₄) in Extracts of Biological Matrices by Gas Chromatography-Mass Spectrometry

Temperature Dependence of the Organic Carbon/Water Partition Ratios (K_OC) of Volatile Methylsiloxanes