Methylene-unit values for steroids were found to be dependent on temperature. A procedure for correction to a reference temperature (275") was investigated and shown to give mean values not signikantly different from vdues determined at the reference temperature although the standard errors of the means were generally signikantly higher. The correlation of temperature-coefZcient valties with steroid structure is discussed in preliminary form.
Calibration with n-alkanes makes possible the expression of retention time data from gas-liquid chromatography (GLC) in terms of methylenz units (MU)' and provides useful -information in many series of compounds including derivatives of amino-and other acids', carbohydrates2 -and prostaglandines3_ The MU. value is on the thermodynamic scale and is analogous to & = log(l -RF)/& in papefi and thin-layer chromatography. Assignment of increments of RM, ARM to structural features provides valuable information in the steroid series%' among many examples.
Thg present study was initiated since MU and bMU values should also-provide information about the structural features of steroids. However, .this report is. con-cern+ with the temperahme dependence of MU vdues, now observed for the first time-. and witli a procedure. for correcting for this temperature efkct so that MU analysis may-be carried out.
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