High Definition X-ray Fluorescence (HD XRF) is used to detect elemental chlorine in products HealthStuff tests. HD XRF is an elemental analysis technique with greater sensitivity than standard XRF. Our instrument from XOS uses monochromatic excitation energies of 7, 17, and 33 keV. The spot size is one millimeter. Elements heavier than aluminum are measurable. Detection limits are in the low parts-per-million (ppm) or sub-ppm range for all elements of interest in this study except chlorine and phosphorus.
For chlorine we consider results above 1,000 ppm to be quantitative. While XRF testing cannot identify molecular structure of organic chemicals, detecting chlorine greater than 3,500 ppm has been successfully used to infer the presence of halogenated flame retardants, depending on the sample matrix. Detection of chlorine greater than 5% (50,000 ppm) suggests the possible presence of PVC polymer, which we can determine through FTIR spectroscopy.
PVC (polyvinyl chloride), otherwise known as vinyl, is a widely used plastic that presents environmental and health hazards during all phases of its life cycle – production, use and disposal. During the production phase, workers at PVC facilities, as well as residents in surrounding areas, may be exposed to vinyl chloride (a building block of PVC) and/or dioxin (an unwanted byproduct of PVC production), both of which are carcinogens. At the end of a product's life, PVC can create dioxin when burned. PVC is not easily recycled.
Because PVC is an inherently brittle material, it requires added plasticizers to make it flexible and to impart other desired properties. A group of plasticizers commonly found in PVC products are phthalates, also called ortho-phthalates. Phthalates are used in many plastics, especially PVC products, as a softening agent to make the plastic flexible. Over 90% of all phthalates are used in PVC products.
Since 2009, the U.S. has prohibited products for children under three years of age and children's toys intended for children under twelve years of age from containing the phthalates DEHP, BBP, and DBP at levels greater than 0.1%. An additional three phthalates, DINP, DnOP, and DIDP, have been placed on a provisional ban by the CPSC unless there is a future determination of safety. These restrictions do not apply to PVC products other than the specified children's products.
Lead and other heavy metals used to be commonly used as stabilizers or to impart other properties to PVC plastic (WTC 2009), especially in electrical wire insulation, and are still sometimes used in that capacity.
Published on September 22, 2016