A semi-empirical model has been developed for additive diffusion in polymers. The model estimates apparent diffusion coefficients of an additive migrating through polyolefin polymers into a fatty food simulant for a range of temperatures between the glass transition and melting temperatures of the polymer. This diffusion model has been applied to several additive/polyolefin systems to determine its validity and limitations.

Resonance and preresonance Raman spectra of Mn and Sc containing argon matrices are reported. For scandium, we assign the progressions to the diatomic and triatomic molecules. The former is found to have vibrational constants ω″e=239.9 cm−1 and ω″ex″e=0.93 cm−1. The latter is best described as an equilateral or near equilateral triangle with a symmetric stretching vibrational frequency of 248 cm−1 and a degenerate (asymmetric stretch–bend) vibrational frequency of 150 cm−1. In addition a low lying electronic state 395 cm−1 above the ground state is attributed to Sc3 based on the observation of a second progression. In Mn containing matrices one identifies three progressions with nearly equivalent vibrational spacings and assigns them to Mn2. The ground state vibrational constants of Mn2 are found to be ω″e=124.7 cm−1 and ω″ex″e=0.24 cm−1. Two more progressions resulting from transitions to states 135.7 and 196.7 cm−1 above the ground state are interpreted by assuming Mn2 to be an antiferromagnetic dimer possessing several spin states whose energy spacings are given by the Landé interval rule. With the frequencies of Mn2 and Sc2 one now has all the frequencies of the first row transition-metal diatomics. The trends across the periodic table are discussed and the properties of diatomics are compared with those of the analogous bulk metals.

An updated survey of U.S. infant formula was conducted to determine the concentrations of bisphenol A (BPA). The purpose was to accurately assess BPA concentrations across the infant formula market, accounting for lot variability, and determine if geographic location or can age influences BPA concentrations. A method was developed to measure BPA in formula utilizing isotope dilution, solid-phase extraction, and liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The method was tested and found to be reproducible (10% relative standard deviation), reliable (47 +/- 1% recovery), and sensitive (0.15 ng g(-1) method detection limit). Over 160 analyses were conducted using 104 formula containers representing 36 products. Samples from U.S. east and west coast markets demonstrated no significant difference, and concentrations in older cans were not higher. BPA concentrations in liquid formula (0.48-11 ng g(-1)) were consistent with previous studies, and BPA was detected in only 1 of 14 powder formula products analyzed.