Combinatorial screening employing nylon loops and micro-X-ray powder diffraction

A combinatorial screening method is described that employs nylon loops and micro-X-ray powder diffraction. The nylon loops are used to position the sample in a three-circle X-ray diffractometer in such a way as to allow for Gandolfi-like scans. These scans maximize mechanical tumbling of the sample, which in turn results in higher quality data. The diffractometer utilizes a pinhole source and two-dimensional area detection for rapid data collection. The method can be readily automated by employing single-crystal screening procedures. The combinatorial analysis of the three known polymorphs of d-mannitol is discussed and a simple procedure to produce all three polymorphs from the same starting solutions is presented.