The procedure and sampler described permits detection of less than 50pg of one polychlorinated naphthalene (PCN) isomer. The method uses gas chromatography-mass spectrometry. The PCNs are collected on a glass fiber filter and two polyurethane foam plugs and extracted with toluene at 25 degrees Celsius. (BB)

This method of image enchancement and real-time imput of 3-D microscopic objects into an optical pattern recognition system is designed to identify and count diatoms as a means of water pollution assessment. The method consists of directing a low-power laser beam into a microscope to produce a coherent image of the specimen. (Author/BB)