| Popis: |
Attempts to measure nitrate at the low levels found in feeds by existing methods failed due to interferences from the soluble organic matter extracted from the samples along with the nitrate. The difficulties increased as the nitrate level decreased. A method for low-level materials was developed in which nitrate was isolated from interfering substances by thin-layer chromatography, eluted quantitatively from the absorbent, and measured colorimetrically by a modification of the 3,4-xylenol method. The procedure will determine nitrate accurately down to 10 ppm or less. |
