1. What is the Flow Equation?

The flow equation calculates the flow rate in a gas chromatography system based on the pressure and conductance. It's a fundamental relationship in GC systems that helps optimize analytical conditions.

2. How Does the Calculator Work?

The calculator uses the flow equation:

Where:

• \( Flow \) — Flow rate (ml/min)
• \( Pressure \) — System pressure (psi)
• \( Conductance \) — Conductance value (unitless)

Explanation: The equation shows the direct proportional relationship between pressure and flow when conductance is constant.

3. Importance of Flow Calculation

Details: Accurate flow calculation is crucial for maintaining optimal carrier gas flow rates, which affects retention times, peak shapes, and overall chromatographic performance.

4. Using the Calculator

Tips: Enter pressure in psi and conductance value. Both values must be positive numbers. The calculator will compute the resulting flow rate in ml/min.

5. Frequently Asked Questions (FAQ)

Q1: What is typical flow rate range for GC?
A: Typical flow rates range from 0.5 to 5 ml/min for capillary columns and 10-50 ml/min for packed columns.

Q2: How does temperature affect flow?
A: Temperature changes affect gas viscosity and thus conductance. The calculator assumes constant temperature conditions.

Q3: What factors affect conductance?
A: Conductance depends on column dimensions, stationary phase, and gas type (He, H2, N2 have different conductivities).

Q4: When should flow be adjusted?
A: Flow should be optimized during method development and checked when changing columns or carrier gas types.

Q5: How accurate is this calculation?
A: This provides an estimate. For precise measurements, use a flow meter at the column outlet.