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. Author manuscript; available in PMC: 2011 Aug 1.
Published in final edited form as: Biochim Biophys Acta. 2010 Mar 20;1800(8):858–870. doi: 10.1016/j.bbagen.2010.03.012

Fig. 8.

Fig. 8

Sucrose gradients obtained by the two layer method. Panel A: Curve a: Layering of 0 and 50% sucrose solutions resulting in a gradient from 12 to 33% sucrose; Curve b: Layering of 0 and 60% sucrose solutions resulting in a gradient from 11 to 43% sucrose; Curve c: Layering of 0 and 70% sucrose solutions resulting in a gradient from 13 to 52% sucrose. Inset: Standard curve of percent sucrose versus measured refractive index (n) of sucrose solutions of known composition and containing 0.15 M NaCl. A least-squares fit of the data yielded the following cubic equation from which the weight percent sucrose of the different gradients was calculated: wt% = 4.3398370×l04 n3 − 1.7268340×105 n2 + 2.2975845×105 n− 1.0222298×105. Panel B: Layering of 4.8 and 23% sucrose samples for various times. (a) 15 min; (b) 30 min; (c) 60 min and (d) overnight. Gradients obtained for curves a, b, c and d were 6.4-22.6, 6.4-23.2, 7.5-22.7 and 12.7-17.3%, respectively. The weight percentage sucrose (w/w) of eleven 1.5 mL fractions from top to the bottom of the centrifuge tube was determined by refractometry.