AN IMPROVED DIFFERENTIAL METHOD FOR THE EXACT DETERMINATION OF SPECIFIC HEATS OF AQUEOUS SOLUTIONS; INCLUDING RESULTS FOR VARIOUS SALTS AND ORGANIC ACIDS

1925 ◽  
Vol 47 (7) ◽  
pp. 1876-1893 ◽  
Author(s):  
Theodore W. Richards ◽  
Frank T. Gucker
Keyword(s):  
Organic Acids ◽  
Aqueous Solutions ◽  
Differential Method ◽  
Specific Heats ◽  
Exact Determination

Formation constants for selected organo—metal (Al3+, Fe3+)—phosphate complexes

1985 ◽  
Vol 63 (12) ◽  
pp. 3357-3366 ◽  
Author(s):  
Paul A. Arp ◽  
W. Lense Meyer
Keyword(s):  
Organic Acids ◽  
Aqueous Solutions ◽  
Reference Electrode ◽  
Formation Constants ◽  
Glass Electrode ◽  
Metal Phosphate ◽  
Electrode Pair ◽  
Phosphate Ions

The possible formation of organo–metal–phosphate complexes (O–M–P) in aqueous solutions is examined by potentiometric titration analysis. The complex-forming solutions contain Al3+-ions or Fe3+-ions, organic acids (salicylic, phthalic, oxalic, and citric acids) and phosphate ions. The titrations are done within the precipitation-free pH-region from 2 to 4.5 (approximately) at 25 °C under nitrogen at an ionic strength of 0.2 M KCl. The calibration of the electrode pair (glass-electrode, calomel-reference electrode) and the determination of the formation constants are facilitated by analyzing the pertinent curves with the ACBA-(Arena etal.) and MINIQUAD-(Gans etal.) computer programs. The results suggest (i) that O–M–P complexes are readily formed, and that the power of selected organic acids to form ternary mixed-ligand complexes with Al3+-ions and phosphate ions decreases in the order salycilate > citrate > oxalate > phthalate. Also, Fe3+-ions are found to be more strongly bound by salicylate and phosphate ions than Al3+-ions. The effect of O–M–P formation on the chemical speciation of Al in buffered aqueous solutions containing mineral nutrients for the growth of biological organisms is demonstrated for a special case study.

INFLUENCE OF DICARBOXYLIC ACIDS ON SOWING QUALITY OF SPRING BARLEY

1970 ◽  
pp. 22-25
Author(s):  
N. N. Loy ◽  
S. N. Gulina
Keyword(s):  
Organic Acids ◽  
Spring Barley ◽  
Dose Range ◽  
Dicarboxylic Acids ◽  
Rotary Machine ◽  
Working Solution ◽  
Negative Effect ◽  
Sprouted Seeds

The effect of presowing seed treatment on various concentrations of dicarboxylic (organic) acids on the sowing characteristics of spring barley has been studied. Seeds were treated with organic acids obtained by exposing cuttings to the radiation with a dose of 100 kGy and consequent hydrolysis, in concentrations: 1•10-7 %; 1•10-9; 1•10-11; 1•10-13 and 1•10-15 % on a laboratory rotary machine RVO-64 for one day before laying for germination. Distilled water was used for the control case. The rate of application of the working solution calculated as 10 liters / ton of seeds. Seeds were germinated in filter paper rolls in accordance with GOST 12038-84 requirements. The temperature was maintained at +24 ° C in the thermostat where the glasses with rolls were placed. For determination of germinative power and laboratory germination the sprouted seeds were evaluated after three and seven days, respectively. In laboratory experiments it was established that the treatment of barley seeds of varieties Zazersky 85, Nur and Vladimir with organic acids (OK) in different concentrations had both a stimulating and a negative effect. On the Zazersky 85 variety, in variants with acid concentrations of 1•10-9 and 1•10-11, an increase in germination energy (EP) by 2-4% and a significant decrease (by 3-4%) of laboratory germination (LV) of barley seeds were noted. On the Nur variety, the increase in EP was observed at 4% (concentration 1•10-11), LV and seed growth force (CPC) by 2-7% at a concentration of 1•10-7 and in the dose range 1•10-11 - 1•10-14 compared to the control values. On the grade of Vladimir, an increase in EP, LV, and CPC was found to increase by 1-6% at concentrations OK 1•10-7 and 1•10-13. It was shown that the treatment of seeds with acids led to an increase in the length of the germ in all studied varieties (by 3-9%) and dry biomass of 7-day-old seedlings - by 3-6%. Consequently, the treatment of seeds with a mixture of dicarboxylic acids has a stimulating effect on the sowing quality of spring barley.

LUMINESCENT DETERMINATION OF SUGAR IN NATURAL HONEY

2020 ◽  
Vol 0 (4) ◽  
pp. 29-32
Author(s):  
B.M. GAREEV ◽  
◽  
A.M. ABDRAKHMANOV ◽  
G.L. SHARIPOV ◽  
◽  
...  
Keyword(s):  
Quantum Dots ◽  
Laboratory Test ◽  
Aqueous Solutions ◽  
Analytical Method ◽  
Sugar Content ◽  
Carbon Quantum Dots ◽  
Photoluminescence Intensity ◽  
Sucrose Content ◽  
Natural Honey

The photoluminescence of carbon quantum dots synthesized from natural honey and mixtures of honey and sugar has been studied. An increase in the sugar content leads to a decrease in the photoluminescence intensity without changing the shape of the luminescence spectrum of these quantum dots aqueous solutions, which is associated with a decrease in the yield of their synthesis in the sugar presence. The discovered effect can be used to detect sugar in honey. When examining five different market samples of flower honey using this method, two of them showed a significant decrease in the photoluminescence intensity. A laboratory test for compliance with GOST 19792-2017 Standard requirements established an excess of the sucrose content in these samples. Luminescent determination of sugar in honey does not require complicated equipment and can be used to develop a new analytical method for determining the sugar content in counterfeit natural honey.

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