Exponential gradient

At the smaller proportions of B, the resolution, although better, can still be improved, so finally in Fig. 4.3j (i) and (ii) we try adding B more slowly at the start of the run by using an exponential gradient and increasing the time. The peaks are now eluted over the entire range of the gradient, and most of the peaks are resolved almost to the baseline. 

Brandley, B. K. and Schnaar, R. L. (1989). Tumor cell haptotaxis on covalently immobilized linear and exponential gradients of a cell adhesion peptide. Dev. Biol. 135, 74-86. 

The column chromatography of the five common phenotypes were also studied by Hopkinson and Harris (H12). A 10-ml aliquot of the supernatant from a centrifuged hemolysate was applied to the DEAE column which had been washed with Tris-phosphate buffer (pH 8.0). The column was then washed with the starting buffer to elute the hemoglobin. The enzyme was eluted with an exponential gradient of sodium chloride in Tris-phosphate buffer and collected in 2-ml fractions at a flow rate of 20 ml/hour. 

An exponential gradient, which reduces the thermomechanical stress in the ceramic region of an FGM by increasing the thickness of this zone, could therefore be detrimental for the crack resistance behaviour of the FGM. 

Mobile phase MeCN water from 35 65 to 100 0 exponentially over 20 min (Waters exponential gradient curve no. 9), keep at 100 0 for 7 min, re-equilibrate at 35 65 for 5 min. Flow rate 2.5 Detector UV 227... 

Mobile phase Gradient. MeCN water from 45 55 to 100 0 over 20 min (exponential gradient), maintain at 100 0 for 5 min, re-equilibrate at initial conditions for 5 min. Column temperature 21 Flowrate 2.5 Ipjection voliune 20 Detector UV 227... 

Depending on the relative values of and the time during which the gradient can be limited either by the initial volume Fq (it is the case for a linear gradient for which pure B is obtained after a time equal to Fg/Sg) or by the volume of solvent B (for an exponential gradient, pure B is obtained after an infinite time, but after a time equal to three times the time constant the eluent contains 95% of B),... 

Fig. 3. Analabs concentration profile modulator for exponential gradients, a = solvent 8 inlet, b = syringe barrel, c = plunger, d = piston seal, e = magnetic stirrer, f = to high-pressure pump.

The parameters required to create a 10-line exponential gradient of 0.2%, 1 nM NGF at the explant using incremental deposition of the volume of chemotropic factor onto the collagen gel, when the concentration of the stock remains constant in the microdispenser... 

Smith, T., and Bell, J. (1986). An Exponential Gradient Maker for Use with Minigel Polyacrylamide Electrophoresis Systems, Biochem. 125 74-77. 

Novotnd et al. [261] studied a set of eight historical anthroquinone and naphthoquinone dyes (carminic acid, laccaic acid A and B, lawsone, juglone, alizarin, lapachol, emodin). They were well resolved in 12 min on a C]g column (A — 270 nm) using a 15-min exponential gradient from 40/60 -y 95/5 methanol/ water (0.1 M citrate pH 2.5). Separately, alizarin and purpurin were resolved on a C]g column (A = 245 ran) using a 72/25 methanol water (0.2 M acetate pH 4.3) mobile phase. Detection limits of 0.6-12 ng injected (analyte dependent) were reported. Linear curves up to the solubility limit of l mM were also used. 

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