Adjustment of the chromatographic elution profiles of different columns by means of variation of column temperature. (a) The same sample was injected onto four different columns kept at the same temperature in a commercially available enforced air circulation oven with Peltier cooling. Because of differences in surface area, retention of DNA fragments varies between columns. (b) Variation of the individual column temperatures allows harmonization of chromatographic profiles. Columns, 4 × monolithic PS/DVB, 60 × 0.2 mm i.d., mobile phase, (A) 100 mM TEAA at pH 7.0, (B) 100 mM TEAA at pH 7.0, 25% acetonitrile; linear gradient, (a) 45%–61% B in 8.0 min, (b) 38%–56% B in 10 min; flow rate, 2.0–3.0 μL/min; temperature, (a) 55°C, (b) 55–57°C; detection, LIF, emission monitored at 525 nm; injection volume, 1 μL each; sample, equimolar mixture of two FAM-labeled 209-bp Y chromosome alleles differing in a single base (168 A>G).