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Column Performance Metrics for SEC

Source: R/polymer-analysis.R
measure_sec_column_performance.Rd

Calculates comprehensive column performance metrics including HETP, separation range, and efficiency parameters.

Usage

measure_sec_column_performance(
  calibration_data,
  column_length = 30,
  column_diameter = 7.8,
  flow_rate = NULL,
  particle_size = NULL,
  dead_volume = NULL
)

Arguments

calibration_data

A data frame containing calibration data with columns:

  • retention or retention_time: Retention time/volume

  • mw or molecular_weight: Molecular weight

  • width: Peak width (optional, for plate calculation)

column_length

Column length in cm. Default is 30 cm.

column_diameter

Column inner diameter in mm. Default is 7.8 mm.

flow_rate

Flow rate in mL/min (optional, for linear velocity).

particle_size

Particle size in micrometers (optional, for reduced HETP).

dead_volume

Column dead volume in mL (optional).

Value

A list of class sec_column_performance containing:

separation_range

MW range (exclusion limit to total permeation)

selectivity

Slope of log(MW) vs retention (mL^-1)

hetp

Height equivalent to theoretical plate (mm)

plates_per_meter

Theoretical plates per meter

reduced_hetp

HETP/particle_size (if particle_size provided)

peak_capacity

Estimated peak capacity in separation range

resolution_factor

Resolution per decade of MW

Details

Key SEC Column Performance Metrics:

HETP (Height Equivalent to Theoretical Plate): $$HETP = \frac{L}{N}$$

Reduced HETP (h): $$h = \frac{HETP}{d_p}$$ Optimal h ~ 2-3 for well-packed columns.

Selectivity (D): $$D = \frac{d \log M}{dV_R}$$ Higher D means better MW resolution.

Peak Capacity: $$n_c = 1 + \frac{\sqrt{N}}{4} \ln\left(\frac{V_{exclusion}}{V_{total}}\right)$$

Typical Performance Guidelines:

  • HETP: < 50 um for analytical columns

  • Reduced HETP: 2-5 for good columns

  • Plates/meter: > 20,000 for HPLC SEC

See also

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

Examples

# From calibration standards
cal_data <- data.frame(
  retention = c(5.2, 6.1, 7.0, 8.2, 9.5, 10.8),
  mw = c(1200000, 400000, 100000, 30000, 5000, 580),
  width = c(0.4, 0.35, 0.30, 0.28, 0.25, 0.30)
)

perf <- measure_sec_column_performance(
  cal_data,
  column_length = 30,
  particle_size = 5
)
print(perf)
#> SEC Column Performance
#> ================================================== 
#> 
#> Separation Range:
#>   Exclusion limit: 1200000 Da
#>   Total permeation: 580 Da
#>   Log MW range: 3.32 decades
#> 
#> Calibration:
#>   Selectivity: 0.5801 log(MW)/unit
#>   R-squared: 0.9956
#> 
#> Column Efficiency:
#>   HETP: 0.070 mm (70.4 um)
#>   Plates/meter: 14203
#>   Reduced HETP (h): 14.08
#>   Average plates (N): 4261
#> 
#> Resolution:
#>   Peak capacity: 12.9
#>   Resolution/decade: 15.99
#> 
#> Column: 300 x 7.8 mm
#> Standards used: 6