SOME FACTORS AFFECTING THE DETERMINATION OF FURFURAL

1948 ◽  
Vol 26b (3) ◽  
pp. 314-324 ◽  
Author(s):  
G. A. Adams ◽  
A. E. Castagne
Keyword(s):  
Sodium Chloride ◽  
Hydrochloric Acid ◽  
Steam Distillation ◽  
Plant Residues ◽  
Titration Method ◽  
Photocolorimetric Determination ◽  
Factors Affecting ◽  
Photocolorimetric Method ◽  
Negative Results

The previous observation by Stillings and Browning that methylfurfural and hydroxymethylfurfural do not interfere with the photocolorimetric determination of furfural with aniline has been confirmed. The color of the furfural – aniline acetate compound was stabilized satisfactorily by oxalic acid and sodium chloride; the addition of disodium phosphate brought about minimum transmittance. Recoveries of furfural distilled from 12% hydrochloric acid were 99.0 and 99.7% as measured by the photocolorimetric and excess bromine titration methods respectively. Xylose was converted to furfural in 90.6% yield by simple distillation with 12% hydrochloric acid saturated with sodium chloride. Rapid steam distillation increased the recovery to 91.6%. Dextrose, levulose, cellulose and rhamnose gave apparent furfural yields by the excess bromine titration method but negative results with the photocolorimetric method. The two methods were applied to 13 plant residues whose furfural contents ranged from more than 30% in 'Beewing' wheat bran to less than 5% for peat. The results obtained by the photocolorimetric method, regarded as being the true furfural contents, are 2 to 3% lower than those obtained by the titration method.

DETERMINATION OF TRACE AMOUNTS OF SILVER IN GALENA ORES

1960 ◽  
Vol 38 (9) ◽  
pp. 1488-1494 ◽  
Author(s):  
E. J. Bounsall ◽  
W. A. E. McBryde
Keyword(s):  
Aqueous Solution ◽  
Nitric Acid ◽  
Sodium Chloride ◽  
Hydrochloric Acid ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Silver Content ◽  
Aqueous Sodium Chloride Solution ◽  
Aqueous Sodium

An analytical method is described for the determination of microgram amounts of silver in galena ores, based on the "reversion" of silver dithizonate. Silver is separated from relatively large amounts of lead by extraction as dithizonate into chloroform from an aqueous 1:99 nitric acid solution. Separation from mercury, which is also extracted under these conditions and would, if present, interfere in the analysis, is achieved by reverting the dithizonate solution with a 5% aqueous sodium chloride solution which is also 0.015 molar in hydrochloric acid. Following dilution of this aqueous solution and adjustment of pH, silver is again extracted into chloroform as the dithizonate, and determined absorptiometrically. Analyses of a number of galena ore samples showed a precision of within 3% for a silver content ranging from 0.03 to 0.4%.Some other methods for isolating silver from these samples, which were tried but found unsatisfactory, are discussed.

THE APPLICATION OF 8-HYDROXYQUINOLINE TO THE ANALYSIS OF ALUMINIUM ALLOYS: DETERMINATION OF MAGNESIUM IN THE PRESENCE OF MANGANESE AND NICKEL

1945 ◽  
Vol 23b (5) ◽  
pp. 183-193
Author(s):  
Paul E. Gagnon ◽  
Henri Shehyn
Keyword(s):  
Sodium Chloride ◽  
Hydrochloric Acid ◽  
Aluminium Alloys ◽  
Accurate Method ◽  
Salting Out ◽  
Co Precipitation ◽  
Short Method

The application of the precipitation of magnesium with oxine in tartro–sodic medium to the analysis of aluminium alloys has been studied from the standpoint of possible interference from other constituents of the alloys and especially manganese and nickel. In the presence of manganese in amounts not exceeding 8.0 mgm. per 100 ml. of solution, magnesium can be successfully determined provided sodium chloride is not present. With amounts of sodium chloride exceeding 6 gm. and manganese over 6 mgm. per 100 ml. of solution, a salting-out of manganese oxinate definitely takes place which leads to high results for magnesium. This interference can be eliminated by preventing the formation of appreciable amounts of sodium chloride by evaporating off hydrochloric acid before adjusting the pH for the precipitation of magnesium oxinate. Nickel in amounts exceeding 2.5 mgm. per 100 ml. of solution interferes by co-precipitation of nickel oxinate, which is adsorbed on the magnesium oxinate and finally leads to high values for magnesium. For this reason, nickel must be removed by means of an ammonium sulphide separation for which a short method is described. With these modifications the precipitation of magnesium with oxine in tartro–sodic medium provides a rapid and accurate method of determining this element in aluminium alloys.

scholarly journals Factors affecting the voluntary intake of food by sheep

1988 ◽  
Vol 59 (1) ◽  
pp. 63-72 ◽  
Author(s):  
W. L. Grovum ◽  
H. W. Chapman
Keyword(s):  
Sodium Chloride ◽  
Hydrochloric Acid ◽  
Monosodium Glutamate ◽  
Latin Square ◽  
Feed Additives ◽  
Acid Salt ◽  
Related Effect ◽  
Sham Feeding ◽  
Factors Affecting ◽  
Voluntary Intake

1. Sheep with oesophageal fistulas were sham-fed on pelleted lucerne (Medicago sativa) hay to assess the palatability of added chemicals representing the tastes of sweet (sucrose), sour (hydrochloric acid), salt (sodium chloride), bitter (urea) and umami (monosodium glutamate; MSG).2. Plain pellets and four concentrations of each chemical were sham-fed for 30 min after 5·5 h deprivation in 5x5 Latin-square experiments following a period of adaptation feeding.3. Sucrose, at concentrations of 15–120 g/kg air-dried pellets, depressed intakes with a linear relation between intake (I; g) and concentration (C; g/kg): I = 1001-3·42C.4. HCl at 6·25–25·0 g/kg pellets had no effect on sham intakes but at 50 g/kg reduced them by 50% of control (P < 0·05).5. NaCl at 50–200 g/kg increased sham intakes by 26% (P < 0·01) with no evidence of a dose-related effect.6. Urea at 10–80 g/kg decreased sham intakes by 26·9% (P < 0·01) with no evidence of a dose-related effect.7. MSG at 5–40 g/kg in two experiments increased sham intakes by 16·1 and 40·8% (P < 0·05). In another experiment at 1-8 g/kg there wasno significant effect.8. When palatability and post-ingestive effects are separated by sham-feeding, the effect of added chemicals on intake may be completely different from when they are ingestednormally (e.g. NaCl and sucrose). This newly developed technique enables the palatabilityeffect of feed additives to be tested critically and economically.

scholarly journals A Method for the Determination of Nicotine in Lung Tissue of Hamsters / Eine Methode zur Bestimmung des Nikotins in Hamsterlungen

1966 ◽  
Vol 3 (6) ◽  
Author(s):  
H. Elmenhorst
Keyword(s):  
Standard Deviation ◽  
Hydrochloric Acid ◽  
Lung Tissue ◽  
Coefficient Of Variation ◽  
Steam Distillation ◽  
Analytical Procedure ◽  
Limit Of Detection ◽  
Experimental Animals ◽  
Inferior Limit

AbstractA method for the determination of nicotine in lung tissue is presented. The nicotine is extracted from homogenized lung tissue by means of a mixture of hydrochloric acid and methanol. It is then spectrophotometrically determined after the disturbing accompanying substances have been eliminated by a preliminary acid steam distillation. The method's inferior limit of detection is 40 µg of nicotine contained in 3 lungs, which corresponds to 17.7 µg of nicotine per gramme of lung tissue. In the case of nicotine contents of 50 µg per analytical procedure the standard deviation of the method was found to be 1.7 µg, and the resulting coefficient of variation was calculated to be 3.4 %. The procedure is simple and therefore suitable for the study of numerous samples. The exposure of hamsters to inhaled raw cigarette smoke revealed that the nicotine content of lungs of experimental animals augments with the number of burnt cigarettes and the duration of inhalation. The reproducibility of Dontenwill's inhalation procedure was tested and proved to be satisfactory. The coefficient of variation within two series of inhalation experiments was found to be between 4.1 and 5.2 %

669. Steam distillation of taints from cream: III. Factors affecting rate of removal of the reference substances, diacetyl and acetoin

1957 ◽  
Vol 24 (2) ◽  
pp. 184-190 ◽  
Author(s):  
F. H. McDowall
Keyword(s):  
Aqueous Solution ◽  
Sodium Chloride ◽  
Salt Solution ◽  
Steam Distillation ◽  
Unit Weight ◽  
Depressing Effect ◽  
Liquid Equilibrium ◽  
Factors Affecting ◽  
Partition Equilibrium

1. The vapour/liquid equilibrium coefficient for diacetyl in 35–40% cream has been found to be of the order of 26–28, compared with 39·3 for water. In a 5% aqueous solution of lactose, equivalent to that present in milk and in cream serum, the coefficient was 30. The depression of the equilibrium coefficient by lactose in solution was shown to be independent of the concentration of diacetyl present in the liquid at time of partition, over the range 1–65 p.p.m.2. The slower rate of removal of diacetyl from cream, per unit weight of steam condensed as compared with its removal from water, was observed to be due mainly to this depressing effect of lactose on the equilibrium coefficient; but there was some evidence that delay in re-establishment of the solubility partition equilibrium as between butterfat and cream serum also contributed to the lowering of the equilibrium coefficient for diacetyl in cream as measured in the laboratory continuous vaporization equilibrium still.3. Sodium chloride in the solution caused a rise in the equilibrium coefficient for diacetyl from the value of 39·3 for water to about 69 for a 10% salt solution and 82 for a 20% salt solution.4. Lactose had no effect on the equilibrium coefficient for acetoin, but salt caused a rise from 1·29 for water to approximately 1·75 for a 10% salt solution.5. The possible effect of lactose on the effectiveness of steam in cream deodorization equipment is referred to.

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