The thermoelectric microdetermination of molecular weight—III

Tomlinson, C.; Chylewski, Ch.; Simon, W.

doi:10.1016/s0040-4020(01)99350-0

Cited by 30 publications

(10 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] have utilized the method of Hill (Ref. 15) to measure either vapor pressure differences or, from these differences, molecular weights of solutes.…”

Section: )mentioning

confidence: 99%

See 1 more Smart Citation

Thermoelectric vapor-pressure osmometry

Adicoff¹,

Murbach²

1967

Anal. Chem.

View full text Add to dashboard Cite

ABSTRACT*The thermoelectric vapor pressure osmometer is established as a satisfactory instrument for the determination of the vapor pressure lowering of solutes in solutions. The calibration constant, a 1 , of the instrument is demonstrated to be independent of the nature of the solute and can be calculated from a knowledge of the system geometry and measurable thermodynamic and transport parameters.Experimental results are evaluated in terms of the change in resistance of the thermistor and the concentration of solution. It is necessary to use a seconddegree equation in concentration plot to fit the data. Evaluation of the coefficient of the second-order term requires the incorporation of a heat-of-mixing term in the form of the Van Laar equation. The concentrationindependent term 8 for the heat of mixing is obtained for fourteen solute-solvent pairs.

show abstract

Section: )mentioning

confidence: 99%

“…12) has reviewed vapor pressure osmometry and calculated thermodynamic efficiencies for a number of solvent systems, and Van Dam (Ref. 13) has optimized a thermoelectric va-por pressure osmotic system using Ohenmocouples and a detailed analysis of the mass and haat transport to measure molecular weights up to 14,000.…”

Section: )mentioning

confidence: 99%

Thermoelectric vapor-pressure osmometry

Adicoff¹,

Murbach²

1967

Anal. Chem.

View full text Add to dashboard Cite

show abstract

“…In that case it could fit Bersted's case I11 and also the theory of Tomlinson et a1. 8 It is clear that certain geometric features of the pendant drop geometry are to 1 X either nonexistent or greatly reduced in the design of Wachter and Simon, but one feature is the same for both. Condensation of solvent into the solution disturbs the concentration equilibrium in the liquid.…”

mentioning

confidence: 99%

Calibration of vapor pressure osmometers for molecular weight measurement

Burge¹

1979

J of Applied Polymer Sci

View full text Add to dashboard Cite

Experimental molecular weights in the range 200 to 100,000 Daltons have been determined by vapor pressure osmometry using three different solvents. For all values in excess of 10,000, molecular weights were also determined by membrane osmometry. The general agreement found for molecular weights determined under a variety of conditions, leads to the conclusion that values as high as 100,000 Daltons can be determined by at least one type of vapor pressure osmometer when it is calibrated with a material of 200 Daltons. Thermistor self‐heating and diffusion in the liquid phase are shown to be unimportant for this particular instrument.

show abstract

“…The earliest reports on differential vapor pressure osmometry were made in the early 1930's by Hill (7) and Baldes (2). Since that time, the basic principles of this method have been explored in some detail with special emphasis on the heat dissipation and mass transfer which take place at the thermistor heat sensing beads (3,4). Several different types of apparatus have been described (3,5,6) employing either thermocouples or thermistors as temperature sensors, but recently a convenient commercial instrument has become available, a vapor pressure osmometer, series 300, from Mechrolab Division of F&M Scientific.…”

mentioning

confidence: 99%

“…Since that time, the basic principles of this method have been explored in some detail with special emphasis on the heat dissipation and mass transfer which take place at the thermistor heat sensing beads (3,4). Several different types of apparatus have been described (3,5,6) employing either thermocouples or thermistors as temperature sensors, but recently a convenient commercial instrument has become available, a vapor pressure osmometer, series 300, from Mechrolab Division of F&M Scientific. In spite of the popularity of this instrument, very little published information has appeared concerning the more practical aspects of its use and it is hoped that the results published here will invoke further critical assessment of the variables which affect molecular weight determinations using this method.…”

mentioning

confidence: 99%

Time dependence and drop size effects in the determination of number-average colecular weight by vapor pressure osmometry

Meeks¹,

Goldfarb²

1967

Anal. Chem.

View full text Add to dashboard Cite

The quantitative effects of drop size and time variations on the determination of molecular weight by vapor pressure osmometry have been considered. The basic theoretical principles underlying this technique are presented. For solutions which give a differential thermistor resistance exceeding a few ohms, resistance decreases linearly with increase in drop size. The importance of time variations is dependent upon solution concentration (and hence differential resistance), the more concentrated solutions reaching a maximum resistance value quicker than dilute solutions. Methods for correcting for both of these effects are explained.

show abstract

The thermoelectric microdetermination of molecular weight—III

Cited by 30 publications

References 22 publications

Thermoelectric vapor-pressure osmometry

Thermoelectric vapor-pressure osmometry

Calibration of vapor pressure osmometers for molecular weight measurement

Time dependence and drop size effects in the determination of number-average colecular weight by vapor pressure osmometry

Contact Info

Product

Resources

About