Biochemical Techniques and Instrumentation

2.7.2.4. Column

a. Conventional columns

Conventional columns are made of stainless steel. They are manufactured to withstand pressures upto 50MPa. They are generally 3-25 cm long and approximately 4-6 mm internal diameter to give a typical flow rates of 1-3 ml/min. At the ends of the columns, porous plug of stainless steel or Teflon are used  to retain the column materials. The stationary phase is packed into a column with particles of 5-10 μm size often containing 40,000-60,000 theoretical plates/m.

b. Microbore or open tubular columns

Microbore or open tubular columns have an internal diameter of 1-2 mm and length of 25-50 cm. This column is packed with 3 or 5 μm particles containing 1,00,000 theoretical plates/m. They can sustain flow rates of 5-20 ml/min. The advantages are reduced mobile phase consumption, increased sensitivity and ideal for interfacing with mass spectrometer.