1.1 This test method covers the determination of silicon in the range from 200 to 500 ppm in engine coolant concentrates by atomic absorption. This method is as accurate and precise as photometric methods, while requiring considerably less operator tim This standard test method covers the determination of silicon in engine coolant concentrates by atomic absorption spectroscopy. Apparatus and reagents used for this test method include atomic absorption spectrometer, hollow-cathode lamp, reagent grade