Tungsten needles are not typically used for High-Pressure Liquid Chromatography (HPLC) applications. In HPLC, a column packed with a stationary phase material is used to separate and analyze components of a mixture based on their chemical properties. The mobile phase, typically a liquid, is pumped through the column at high pressure to facilitate separation. Tungsten needles are not suitable for this application because they are typically used for physical manipulation rather than chemical separation. The materials used for HPLC columns are carefully selected for their chemical compatibility, stability, and other properties that are important for separation.
