Organophosphate esters and phthalate esters are commonly used as additives in numerous building materials and consumer products. The use of these compounds is increasing, and phosphate and phthalate esters are to be regarded as ubiquitous contaminants in the indoor environment. These compounds comprise a number of different compounds that have been associated with biologic effects in animal studies as well as in humans. Thus, it is of concern to increase the knowledge about human exposure of these compounds because of their presence in indoor air. In this paper, thirty indoor environments have been surveyed with respect to seventeen of the most abundant of these compounds.

This paper presents an algorithm and method for peak alignment or spectral synchronization of firstorder data with pronounced differences between baseline and signals of interest, e.g. data typically acquired by NMR, MS, GC, LC and CE. The method preserves the shapes of peaks, merely altering their positions on the x-axis of the data set. The method involves coarse discrimination between baseline and peaks, generation of a sparse vector or a list representing peak maximum positions, and analysis of the vector or list for shift parameters using breadth first search or dynamic programming. The method can align peaks up to the spectral resolution of the acquiring instrument without restrictions on the number of peaks that are to be shifted. Furthermore, the speed and moderate number of meta-parameters of the algorithm make the method suitable for on-line implementation. Real 1 H NMR and GC data are used to illustrate the method's performance.

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