Calculating Optimal Modulation Periods to Maximize the Peak Capacity in Two-Dimensional HPLC

Abstract

Theoretical calculations are presented to optimize modulation period for maximum total peak capacity in comprehensive two-dimensional HPLC (2D-HPLC) taking into account the effect of modulation on the apparent peak capacity of the first-dimension (1D) separation. Results indicate that modulation periods are most favorable when they are adjusted to approximately 2.2-4 times the standard deviation of a 1D peak in order to avoid excessively short run times at the second dimension (2D). Data are presented that effective peak capacities of several thousand in 60 min can be expected for practical 2D-HPLC conditions, utilizing 1D gradient elution followed by 2D isocratic elution, that remain at approximately 50-70% of the theoretical maximum peak capacity. This work suggests that lower modulation frequencies and longer 2D separation times than previously proposed are favorable under realistic chromatographic conditions, alleviating some practical problems associated with 2D-HPLC.

Accumulating resampling (modulation) in comprehensive two‐dimensional capillary GC (GC×GC)

“…Parameters recommended in refs. [2,3,5,6] corresponded to the lowest acceptable (rather than optimal) sampling densities due to unpredictable harm at much lower densities. Recommended parameters based on the experimental data for LC6LC [2,6] with its incompressible mobile phase could be compared with optimal parameters found here for GC6GC with small gas decompression in the second-dimension column.…”

“…Sampling periods recommended for accumulating [2,6] and snapshot [3,5] resampling are known from several reports where they were obtained from computer simulations of Gaussian peaks. In most cases, the simulations were complimented by the experimental data [2,5,6].…”

“…In most cases, the simulations were complimented by the experimental data [2,5,6]. All studies arrived at more or less the same recommendations, but provided no means for quantitative evaluation of the effects of several important factors on the outcome of the resampling.…”

Comprehensive two-dimensional liquid chromatographic analysis of anthocyanins

“…In a later study by Horie and co-workers [113], it was shown that the best compromise between sampling rate and second dimension analysis time in on-line LC×LC can be achieved when each first dimension peak is sampled a minimum of two times. The reason for this is that, while increased sampling rates are required to maintain first dimension resolution, the use of shorter second dimension analyses comes with a reduction in peak capacity in this dimension, ultimately lowering the overall peak capacity.…”

Determination of Pesticides in Complex Samples by One Dimensional (1D-), Two-Dimensional (2D-) and Multidimensional Chromatography

“…Tanaka et al (Horie et al, 2007) showed that the sampling time applied for the second dimension ( 2 D separation) should be adjusted to 2-4 times the standard deviation of the firstdimension ( 1 D separation) peak (i.e., one or two 'cuts' per 1 D peak). This yields the best compromise between the time available for the 2 D separations and maintaining separation obtained in the first dimension (Eeltink et al, 2009).…”