Determination of Boiling Points of Pure Organic Liquids. A Micromethod for use With Reduced Pressures

1943 ◽  
Vol 15 (10) ◽  
pp. 648-649 ◽  
Author(s):  
Celso Garcia
Keyword(s):  
Organic Liquids ◽  
Boiling Points ◽  
Reduced Pressures

The determination of normal boiling points at high altitudes

1957 ◽  
Vol 34 (9) ◽  
pp. 440 ◽  
Author(s):  
Luis Levy ◽  
Oswaldo E. Proano
Keyword(s):  
High Altitudes ◽  
Boiling Points

Characterization of Matrix-Assisted Laser Desorption Based on Absorption and Acoustic Monitoring

1995 ◽  
Vol 49 (12) ◽  
pp. 1826-1833 ◽  
Author(s):  
Jan Preisler ◽  
Edward S. Yeung
Keyword(s):  
Atmospheric Pressure ◽  
Accurate Determination ◽  
Optimal Conditions ◽  
Plume Velocity ◽  
Ion Laser ◽  
Optical Probing ◽  
Argon Ion ◽  
Reduced Pressures

Conventional methods for studying matrix-assisted desorption-ionization rely on mass spectroscopy. In this study, a 488-nm argon-ion laser beam is deflected by two acoustooptic deflectors to image plumes desorbed at atmospheric pressure via absorption. All species, including neutral molecules, are monitored. Interesting features, e.g., differences between the initial plume and subsequent plumes desorbed from the same spot, or the formation of two plumes from one laser shot, are observed. Total plume absorbance can be correlated with the acoustic signal generated by the desorption event. A model equation for the plume velocity as a function of time is proposed. Optical probing also enables accurate determination of plume velocities at reduced pressures. These results define the optimal conditions for desorbing analytes from matrices, as opposed to achieving a compromise between efficient desorption and efficient ionization as is practiced in mass spectrometry.

scholarly journals On the capacity for heat of water between the freezing and boiling points, together with a determination of the mechanical equivalent of heat in terms of the international electrical units.―Experiments by the continuous-flow method of calorimetry performed in the Macdonald Physical Laboratory of McGill University, Montreal

1901 ◽  
Vol 67 (435-441) ◽  
pp. 238-244 ◽  
Keyword(s):  
Specific Heat ◽  
Continuous Flow ◽  
Thermal Capacity ◽  
Boiling Points ◽  
Physical Laboratory ◽  
Complete Work ◽  
Different Temperatures ◽  
Mcgill University ◽  
Continuous Flow Method

At the Toronto meeting of the British Association in 1897, a new method of calorimetry was proposed by Professor Callendar and the author for the determination of the specific heat of a liquid in term of the international electrical units. At the Dover meeting ii September, 1899, some of the general results obtained with the method for water over a part of the range between 0° and 100 were communicated, with a general discussion of the bearing of the experiments to the work of other observers. In the present paper the author gives a summary of the complete work, in the case of water, to determine the thermal capacity at different temperatures between the freezing and boiling points.

EBULLIOMETRY AND THE DETERMINATION OF THE MOLECULAR WEIGHTS OF POLYMERS: PART III. CONSIDERATIONS ON THERMISTOR WHEATSTONE BRIDGES

1959 ◽  
Vol 37 (12) ◽  
pp. 1365-1373 ◽  
Author(s):  
W. R. Blackmore
Keyword(s):  
Atmospheric Pressure ◽  
Background Noise ◽  
Wheatstone Bridge ◽  
Thermistor Bridge ◽  
Molecular Weights ◽  
Boiling Points ◽  
Pure Solvent ◽  
Unbalance Voltage

It is shown that a d-c. thermistor Wheatstone bridge may be used in ebulliometry to measure the small temperature differences which are observed between the boiling points of polymer solutions and the pure solvent. A relationship is derived between the thermistor bridge unbalance voltage and the solute molecular weight, which it is desired to measure. It is shown that a bridge composed of suitably matched thermistors may be made independent of the gross changes in boiling point of both solution and solvent produced by changes in atmospheric pressure. The possibility of the current flowing through the thermistors disturbing the measurements is discussed and in situ measurements of thermistor dissipation and time constants are given. The sensitivity attainable with various thermistor bridges and modern amplifiers at full gain is calculated and shown to be much greater than may be employed with the usual type of ebulliometer. The reason for this is the relatively large background noise (random temperature fluctuations) produced in the ebulliometer by the boiling process itself.

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