In late 2018 and 2019, we purchased thirteen crib mattresses from major retailers. Mattresses were selected to capture a range of price points, popular brands, and styles. We separated each into components for testing and placed the components into 3 basic categories: cover (and layers thereof), core (and padding), and fire barrier wraps. Pieces were cut with scissors and immediately placed into clean plastic sample bags. Scissors were cleaned with isopropanol before and after each cut.
A total of 102 components were taken from the crib mattresses.
Mattress components were subject to 5 different analytical techniques:
High-definition X-ray fluorescence (HD XRF)
Each of the 102 mattress components were screened for elements of interest by HD XRF using an HD Prime spectrometer by XOS. This technique measures levels of elements above aluminum on the periodic table. This includes toxic metals such as lead and cadmium as well as bromine, chlorine, and phosphorus that, in depending on the matrix, indicate flame retardant chemicals.
Fourier Transform Infrared (FTIR) spectroscopy
Most components were analyzed by FTIR to determine the polymer or fiber type (for example, cotton or polyethylene). A subset were also subject to solvent extraction followed by FTIR to test for the presence of additives such as plasticizer chemicals.
Chromatography coupled with mass spectrometric methods
Six of the crib mattresses had PVC (vinyl) covers, all of which we sent to a commercial lab, TUV Rheinland, for detection of plasticizer chemicals. The plasticizers analyzed included orthophthalates, DOTP, DINCH, benzoate esters (trade name Benzoflex), and adipates.
In addition, 29 crib mattress components--cores and fire barrier wraps--were analyzed by a highly sensitive technique (liquid chromatography with mass spectrometry, LC/MS/MS) at Indiana University to measure 82 flame retardant and related chemicals, including brominated, phosphorus-based, and melamine compounds. In addition, 7 crib covers were analyzed by LC/MS/MS for 43 PFAS compounds, including PFOA and PFOS.
Particle-induced gamma ray excitation (PIGE)
Outer covers, including their tops, sides and bottoms if made of different materials, were subject to PIGE at the University of Notre Dame to determine total fluorine content. Total fluorine above approximately 100 ppm suggests the presence of PFAS chemicals when other sources of fluorine are ruled out.
Dr. Marta Venier, Indiana University
Dr. Graham Peaslee, University of Notre Dame