Calculate Theoretical Plate Count

Calculates the number of theoretical plates (N) for a chromatographic peak, a measure of column efficiency.

Usage

measure_sec_plate_count(
  retention,
  width,
  width_type = c("half_height", "baseline", "inflection"),
  dead_time = NULL
)

Arguments

retention

Retention time of the peak.

width

Peak width. See width_type for measurement method.

width_type

Type of peak width measurement:

• "half_height" (default): Width at 50% height (W0.5h)

• "baseline": Width at baseline from tangent lines (Wb)

• "inflection": Width at inflection points (Wi)

dead_time

Column dead time (t0). If provided, calculates effective plates (N_eff) using adjusted retention time.

Value

Numeric plate count. Higher values indicate better efficiency.

Details

Theoretical plate count measures column efficiency:

Half-height width (most common): $$N = 5.54 \left(\frac{t_R}{W_{0.5h}}\right)^2$$

Baseline width: $$N = 16 \left(\frac{t_R}{W_b}\right)^2$$

With dead time correction (effective plates): $$N_{eff} = 5.54 \left(\frac{t_R - t_0}{W_{0.5h}}\right)^2$$

Typical SEC Performance:

• Analytical SEC columns: 10,000-40,000 plates/meter

• Preparative columns: 5,000-15,000 plates/meter

• UHPLC SEC: 50,000+ plates/meter

See also

Other sec-qc: measure_sec_asymmetry(), measure_sec_column_performance(), measure_sec_recovery(), measure_sec_resolution(), measure_sec_suitability()

Examples

# Calculate plate count for a monomer peak
measure_sec_plate_count(
  retention = 9.5,
  width = 0.25,
  width_type = "half_height"
)
#> [1] 7999.76

# With dead time for effective plates
measure_sec_plate_count(
  retention = 9.5,
  width = 0.25,
  dead_time = 3.0
)
#> [1] 3745.04