Determination of Small Amounts of Secondary Amine in High Molecular Weight Fatty Primary Amines

1959 ◽  
Vol 31 (10) ◽  
pp. 1655-1657 ◽  
Author(s):  
A. J. Milun ◽  
J. P. Nelson
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Secondary Amine ◽  
Primary Amines

CONJUGATED OESTROGENS. I

1963 ◽  
Vol 43 (3) ◽  
pp. 345-360 ◽  
Author(s):  
Stanley Kushinsky ◽  
Jane (Wu) Tang
Keyword(s):  
Molecular Weight ◽  
Formic Acid ◽  
Ethyl Acetate ◽  
High Molecular Weight ◽  
Secondary Amine ◽  
Aqueous Ammonia ◽  
Organic Solution ◽  
Extraneous Material

ABSTRACT A convenient and mild procedure is described in this paper whereby free and conjugated oestrogens may be extracted from urine. The extracts containing approximately 90 per cent of the oestrogens are devoid of most of the extraneous material and may be reduced in volume to less than 1/15 of that of the urine. The procedure consists of the following steps: (1) a 10 per cent (v/v) solution of a high molecular weight secondary amine (Amberlite LA-2, Rohm and Haas) in ethyl acetate is washed with formic acid and water, (2) the oestrogens in urine (acidified to pH 2 or 3 with H2SO4) are extracted with the LA-2 solution, (3) the oestrogen fraction is back-extracted from the organic solution with dilute aqueous ammonia.

scholarly journals Effects of Delayed Sample Processing on Determination of Total and High Molecular Weight (HMW) Adiponectin in Serum and Plasma: A Pilot Study

2016 ◽  
Vol 8 (3) ◽  
pp. 19
Author(s):  
Choaping Ng ◽  
Felicity J Rose ◽  
Sahar Keshvari ◽  
Marina M Reeves ◽  
Goce Dimeski ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Pilot Study ◽  
High Molecular Weight ◽  
Accurate Determination ◽  
Mean Difference ◽  
Serum Samples ◽  
Blood Samples ◽  
Hmw Adiponectin ◽  
Total Adiponectin

<p>Adiponectin is a beneficial adipocyte-secreted hormone, which circulates in a variety of multimeric forms termed low and high molecular weight (LMW/HMW). Effectiveness of clinical therapeutic trials which target adiponectin rely on accurate determination of circulating total and HMW adiponectin levels but the accuracy may be influenced by variations in sample handling processes. The aim of this pilot study was to investigate the effects of delayed processing of blood samples on the concentration of total and HMW adiponectin.</p><p>Materials and Methods: Fasting blood samples were collected for analysis of total and HMW adiponectin concentrations in EDTA plasma and serum from eight healthy participants.  Samples were centrifuged post 15 min storage at 4<sup>o</sup>C as the comparative ‘ideal’ method or after up to 72 h of refrigerated storage or 6 h at room temperature. Total and HMW adiponectin concentrations were measured by ELISA.</p><p>Results: Under ideal handling conditions measurements of total and HMW adiponectin concentrations were significantly higher in serum than in plasma (mean difference: -1.3 µg/mL [95% CI: -1.6, -1.0], p&lt;0.001; and, -0.6 µg/mL [95% CI: -0.7, -0.5], p&lt;0.001, respectively).  Storage of blood samples at 4<sup>o</sup>C for 72 h resulted in significant reductions in concentration of total adiponectin in serum (mean difference: -1.4 µg/mL [95% CI: -2.0, -0.8], p=0.001) and HMW adiponectin in plasma (mean difference: -0.6 µg/mL [95%CI: -0.9, -0.2], p=0.007), compared with ideal conditions.  Further analysis of serum samples showed a significant decrease in total adiponectin concentration after 6 h storage at 4<sup>o</sup>C (mean difference: -1.4 µg/mL [95% CI: -2.0, -0.8], p=0.001) compared with ideal conditions.</p><p>Conclusions: Delayed processing of samples may have differential effects on the concentration of total and HMW adiponectin in serum or plasma. Larger studies are warranted for clinical intervention trials.</p>

Determination of Peroxides in Synthetic Rubbers

1945 ◽  
Vol 18 (4) ◽  
pp. 874-876
Author(s):  
Richard F. Robey ◽  
Herbert K. Wiese
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Quantitative Determination ◽  
High Molecular Weight ◽  
Active Oxygen ◽  
Lower Molecular Weight ◽  
Synthetic Rubber ◽  
High Molecular Weight Polymers ◽  
Methanol Solutions

Abstract Peroxides are found in synthetic rubbers either as the result of attack by oxygen, usually from the air, or as a residue from polymerization operations employing peroxide catalysts. Because of possible detrimental effects of active oxygen on the properties of the rubber, a method of quantitative determination is needed. The concentration of peroxides in substances of lower molecular weight may be determined with ferrous thiocyanate reagent, either titrimetrically as recommended by Yule and Wilson or colorimetrically as by Young, Vogt, and Nieuwland. Unfortunately, many highly polymeric substances are not soluble in the acetone and methanol solutions employed in these procedures. This is also the case with hydrocarbon monomers, such as butadiene, containing appreciable concentrations of soluble high molecular weight polymers. Bolland, Sundralingam, Sutton and Tristram recommended benzene as a solvent for natural rubber samples and the reagent made up in methanol. However, most synthetic rubbers are not readily soluble even in this combination. The following procedure employs the ferrous thiocyanate reagent in combination with a solvent capable of maintaining considerable concentrations of synthetic rubber in solution. The solvent comprises essentially 20 per cent ethanol in chloroform.

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