Multi-Technique Analysis of Cleaning Products for Target Component
Is Your Cleaner...Clean?
Amy Porter, Senior Analytical Leader
Karen Griffin, Senior Analytical Chemist
A customer submitted fifteen cleaning products to be analyzed for a variety of target compounds.
The products ranged from non-viscous multipurpose cleaners to extremely viscous laundry detergents; all submitted samples were scented. The samples were screened for bromodichloromethane (BrCCl2), acetaldehyde, methanol, acetone, methylene chloride, chloroform, 1,4,-dioxane, ethylene oxide, formaldehyde and bisphenol A (BPA) using gas chromatography (GC) with a combination of electron capture (ECD), flame ionization (FID), and mass spectral (MS) detection. Samples were injected by both headspace (HS) and liquid injection. Three analytes were screened for by liquid chromatography-mass spectromety (LC-MS): sodium dodecyl sulfate (SDS), nitrilotriacetic acid (NTA) and 3-(dimethylamino)-1-propylamine (DMPA) and a full metal screen was performed on all of the samples using inductively coupled plasmaoptical emission spectroscopy (ICP-OES).
The complexity of the samples required a variety of preparation techniques, particularly for the GC analyses. Liquid/liquid extraction, solid phase extraction and headspace analyses were utilized to minimize interferences and maximize sensitivity. Example GC-MS chromatograms obtained for a laundry detergent without sample clean-up and with sample clean-up are shown in Figures 1 (page 2) and 2 (page 3). The target analyte for these analyses was BPA; an expanded chromatogram showing the detection of a BPA peak is shown in Figure 3 (page 4). The method used in Figure 1 resulted in a complex chromatogram with interfering peaks; the sample preparation utilized for Figures 2 and 3 allowed for detection and quantitation of BPA.
The GC and LC-MS results are summarized in Table 1, below. Inorganics detected by ICP-OES analyses included aluminum, calcium, strontium, zinc, silicon, and sulfur.
Figure 1. GC-MS chromatogram obtained for a laundry detergent with no sample clean-up step
Figure 2. GC-MS chromatogram obtained for a laundry detergent with a sample clean-up step
Figure 3. GC-MS expanded chromatogram obtained for a laundry detergent with a sample clean-up step, highlighting the detection of BPA.