The development of molecularly imprinted chiral stationary phases has traditionally been limited by the need for a chiral pure template. Paradoxically, availability of a chiral pure template largely defeats the purpose of developing a chiral stationary phase. To solve this paradox, imprinting of scalemic and racemic template mixtures was investigated using both chiral (N-α-bismethacryloyl-L-alanine) and achiral (N,O-bisacrylamide ethanolamine) crosslinkers. Imprinting of scalemic mixtures provided polymers capable of partial separation of Boc-tyrosine enantiomers with virtually the same results when using either the chiral or achiral crosslinker. However, the chiral crosslinker was required for chiral differentiation by the racemic imprinted polymers which were evaluated in both batch rebinding and chromatographic modes. Batch rebinding analysis revealed intersecting binding isotherms for the L- and D-Boc-tyrosine, indicating bias for the D or L enantiomer is concentration dependent. Partial chromatographic separation was achieved by the racemic imprinted polymers providing variable D or L bias in equal probability over multiple replicates of polymer synthesis. Correlation of enantiomer bias with the batch rebinding results and optimization of HPLC parameters are discussed.

Abstract1,4‐Dioxane, a co‐product that forms during the preparation of ethoxylated surfactants, particularly sulfated and phosphorylated ethoxylates, is classified as a potential human carcinogen whose occurrence in surface water and groundwater is of particular concern. As a result, the US state of New York has passed laws that will limit the concentration of 1,4‐dioxane to ppm levels in household cleansing, personal care and cosmetics products, all of which commonly employ ethoxylated fatty alcohol sulfate surfactants and California is considering such laws. This review first assesses the methodologies used to quantify 1,4‐dioxane in surface water and drinking water, then extends the assessment to commercially available products, which are more complex sample matrices than water. Our assessment indicates that gas chromatography using conventional capillary columns and mass spectrometric detection, and the employment of an internal standard, particularly 1,4‐dioxane‐d8, is the best approach. A means of isolating and concentrating 1,4‐dioxane from the commercial samples is critical to achieve resolution at the sub‐ppm level and to minimize interference from contaminants present in the sample matrix. We review the different concentration approaches, such as headspace analysis, liquid–liquid and solid‐phase extraction, purge‐and‐trap, and solid‐phase microextraction, and evaluate their advantages and disadvantages for the robust long‐term assessment of 1,4‐dioxane levels in commercial products.

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