Pittcon 2014 Posters
Presented in Chicago, IL at Pittcon 2014 held March 2-6, 2014.
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Fast PDMS Quantitation Using ICP-OES
-Barbara Pavan & Katherine Robertson
The reliable quantification of polydimethylsiloxanes (PDMS) in aqueous media is made challenging by their ubiquitous presence in the environment and their ability to "stick" to surfaces. Herein we present a method developed for quantifying Antifoam C (30 wt % PDMS) in aqueous solutions, by inductively coupled plasma-optical emission spectroscopy (ICP-OES), using a Thermo iCAP 6300 Duo. Our method, which determines the PDMS content from the total silicon, is based on a simple extraction in organic solvents and produced good recoveries for both high and low silicon contents. With this method we proved that PDMS can be measured reliably and with minimal sample preparation (i.e. avoiding acid digestion) via total silicon content.
A Multiple GC-MS & LC-MS Approach for the Identification and Quantification of Polymer Additives
-John Roy & Amy Porter
A multiple technique approach has been developed for the identification of polymer additives. The first step in the process involves chloroform extraction of the additives from the polymer. The extract is analyzed using gas chromatography-mass spectrometry (GC-MS) followed by liquid chromatography-mass spectrometry (LC-MS). As many additives as possible are identified from the GC-MS analysis. An ion trap mass spectrometer is used for the LC-MS analysis, which affords multiple levels of fragmentation to assist in the identification of unknown compounds. An ultraviolet detector is coupled with the LC-MS instrument to identify compounds having UV chromophores and to confirm compounds have not been missed during the LC-MS analysis. The advantage of this combined GC-MS / LC-MS approach is that often an additive is detected by one technique, but not the other. A second advantage of the process, the GC-MS data can be searched in spectral databases leasing to the identification of many compounds that may also be detected by LC-MS. This leads to less data interpretation for the LC-MS data. Additional structural assignments are made using an internally generated LC-MS database and an internal database of known polymer additives. After identification of unknown compounds, quantitation of the additives can be achieved using the most appropriate instrument. Examples of this approach and improvements for this process are presented.
Analysis of Odorous Consumer Products Using Gas Chromatography Coupled to Mass Spectrometry and Olfactory Detection
-Amy Porter & Karen Griffin
Consumer products are often stored in large warehouses and transported in trucks with a variety of other products. As the temperature of these facilities rise, the compatibility of the products can become an issue. If a highly odorous product is stored to closely to, or shipped with, an odor absorbent product, odor and taste issues can result. In this work, solid phase microextraction (SPME) was used to sample the air around odorouse consumer products. The samples were analyzed via gas chromatography (GC) coupled to mass spectrometry (MS) and olfactory detection, run in parallel. This allowed for odors to be recorded even when the concentration was too low for the MS detection, but still significantly high enough for human detection. The method used in this work could be used to establish appropriate storage distances in warehouses and the compatibility of products that may be shipped together. Additionally, the use of SPME fibers allows for some selectivity of the components being sampled through the choice of fiber coating, therefore further tuning of the method could be performed if needed.