A rapid micro-method for the determination of melting-point

1936 ◽  
Vol 32 ◽  
pp. 741 ◽  
Author(s):  
R. C. Ray ◽  
V. Dayal
Keyword(s):  
Melting Point

EINE CHEMISCHE METHODE ZUR BESTIMMUNG VON 16-EPI-ÖSTRIOL IM URIN DES MENSCHEN

1963 ◽  
Vol 44 (1) ◽  
pp. 47-66 ◽  
Author(s):  
W. Nocke ◽  
H. Breuer
Keyword(s):  
Melting Point ◽  
Phosphoric Acid ◽  
Aqueous Alkali ◽  
Percentage Error ◽  
Organic Layer ◽  
Maximum Percentage ◽  
Chemical Determination ◽  
Routine Assay ◽  
Hydrolysis Of

ABSTRACT A method for the chemical determination of 16-epi-oestriol in the urine of nonpregnant women with a qualitative sensitivity of less than 0.5 μg/24 h is described. The separation of 16-epi-oestriol and oestriol is accomplished by converting 16-epi-oestriol into its acetonide, a reaction which is stereoselective for cis-glycols and therefore not undergone by oestriol as a trans-glycol. Following partition between chloroform and aqueous alkali, the acetonide of 16-epi-oestriol is completely separated with the organic layer whereas oestriol as a strong phenol remains in the alkaline phase. 16-epi-oestriol is chromatographed on alumina as the acetonide and determined as a Kober chromogen. This procedure can easily be incorporated into the method of Brown et al. (1957 b) thus making possible the simultaneous routine assay of oestradiol-17β, oestrone, oestriol and 16-epi-oestriol from one sample of urine. The specificity of the method was established by separation of 16-epi-oestriol from nonpregnancy urine as the acetonide, hydrolysis of the acetonide by phosphoric acid, isolation of the free compound by microsublimation and identification by micro melting point, colour reactions and chromatography. The accuracy of the method is given by a mean recovery of 64% for pure crystalline 16-epi-oestriol when added to hydrolysed urine in 5–10 μg amounts. The precision is given by s = 0.24 μg/24 h. For the duplicate determination of 16-epi-oestriol the qualitative sensitivity is 0.44 μg/24 h, the maximum percentage error being ± 100% The quantitative sensitivity (±25% error) is 1.7 μg/24 h.

scholarly journals ПОЛІМЕР-ПОЛІМЕРНИЙ КОМПОЗИТ НА ОСНОВІ ВІДХОДІВ ЗШИТОГО ЕТИЛЕНВІНІЛАЦЕТАТУ

2019 ◽  
Vol 128 (6) ◽  
pp. 64-70
Author(s):  
Б. П. Савчук ◽  
Б. М. Савченко ◽  
Н. В. Сова ◽  
І. М. Костюк
Keyword(s):  
Mechanical Properties ◽  
Melting Point ◽  
Polymer Composite ◽  
Constant Pressure ◽  
Capillary Viscometer ◽  
Hydrostatic Weighing ◽  
Weighing Method ◽  
Hydrostatic Weighing Method

Development of technology for the processing of cross liked EVA waste, followed by the use of polymer / polymer composite PVC / EVA as a filler. Method. The determination of the MFI was carried out in accordance with ISO 1133: 1997 on a capillary viscometer of constant pressure at a temperature of (190 ± 0,5) ° С and a weight of 2,16 kg. The thermostability  and  melting  point  are  determined  using  the  RM-200C  Hapro  rheometer  plastograph.  The mechanical properties were determined on a bursting machine according to the ASTM D638. Hardness - using  a  hard-gauge  with  a  Shore-D  scale,  the  density  by  hydrostatic  weighing  method  on  the  analytical scales RADWAG AS-X2.

The Gallium Melting-Point Standard: A Determination of the Liquid—Solid Equilibrium Temperature of Pure Gallium on the International Practical Temperature Scale of 1968

1977 ◽  
Vol 23 (4) ◽  
pp. 719-724 ◽  
Author(s):  
Donald D Thornton
Keyword(s):  
Melting Point ◽  
Melting Temperature ◽  
Temperature Scale ◽  
Equilibrium Temperature ◽  
Melting Range ◽  
Practical Temperature ◽  
Practical Temperature Scale ◽  
Gallium Melting Point

Abstract The sharpness and reproducibility of the gallium melting point were studied, and the melting temperature of gallium in terms of IPTS-68 was determined. Small melting-point cells designed for use with thermistors are described. Nine gallium cells including three levels of purity were used in 68 separate determinations of the melting point. The melting point of 99.99999% pure gallium in terms of IPTS-68 is found to be 29.7714 ± 0.0014 °C; the melting range is less than 0.0005 °C and is reproducible to ±0.0004 °C.

Evaluation of Color Additives Using a Differential Scanning Calorimeter

1970 ◽  
Vol 53 (2) ◽  
pp. 244-249
Author(s):  
Daniel M Marmion
Keyword(s):  
Melting Point ◽  
Moisture Content ◽  
Differential Scanning Calorimeter ◽  
Relative Stability ◽  
Heat Of Fusion ◽  
Permanent Record ◽  
Natural Color ◽  
Sensitive Tool ◽  
Similar Information

Abstract DSC is a rapid and sensitive tool for the determination of the melting point, moisture content, purity, and heat of fusion of certifiable colors. The relative stability and the identification of the colorants may also be deduced from the thermograms. The procedures outlined require only a few milligrams of sample and provide a permanent record. Attempts to obtain similar information for natural color additives were unsuccessful due to the inability to obtain reproducible thermograms.

Cooperative determination of the melting point of alumina

1970 ◽  
Vol 21 (1) ◽  
pp. 115-122 ◽  
Author(s):  
S. J. Schneider
Keyword(s):  
Melting Point
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