Search

ポリアクリロニトリルをアルカリで処理した場合に起こる着色現象を検討するためにCH3 [CH (CN) CH2] 1-4Hの構造をもった模型物質を使用した。そしてポリアクリロニトリルから誘導された着色体の単位構造と推定される物質を逐次合成した。これらの模型物質をジメチルホルムアマイド中でKOHで処理し, その時の紫外吸収スペクトルの変化を測定した。その結果CH3 [CH (CN) CH2] 2-4Hの場合は環状構造が形成され, CH3 [CH (CN) CH2] 3-4Hの場合には同時に着色を伴うことが認められた。この着色の原因を調べるためグルタロイミド環をもつ誘導体およびグルタロイミジン環をもつ誘導体を合成し, KOHによる着色性, および紫外吸収スペクトルに関して検討した結果, グルタロイミド環はポリアクリロニトリルの着色構造には無関係であるが, グルタロイミジン環をもつ誘導体の合成のときにCH3 [CH (CN) CH2] 3HをNaNH2で処理して得られたオクタハイドロ-2, 7-ジイミノ-3, 6-ジメチル-1, 8-ナフ チリジンがポリアクリロニトリルの着色構造の単位構造構型であると考えられ, ポリアクリμニトリルの着色の原因がナフチリジン環類似構造の形成にあるという従来の仮説を本質的に証明することができた。

A simple, rapid, and accurate spectrophotometric procedure for the determination of beryllium in airborne dust samples has been developed, with aluminon reagent used for color formation. The use of a complexing buffer solution containing one complexing and two chelating agents improves on the specificity of previous methods. In contrast to the Zenia method which has a lower limit of 2.5 μg, the present procedure is much more sensitive and affords accurate results for beryllium contents as low as 0.6 μg. Also, the procedure is rapid, as many as 40 samples having been analyzed in a normal 8-hr work period by a single analyst.

A study was conducted to characterize the solid phases of cadmium-sulfur-selenium red pigments. Continuous solid solution of CdS and CdSe and obedience to Vegard's law were confirmed by X-ray diffraction analysis. An increased rate of color formation was realized by using smaller reactant particles. Thermal decomposition of the CdS-CdSe solid solution involved the reappearance of the CdS-CdSe mixtures with subsequent transformation of these resulting compounds.

The cobalt, nickel and copper complexes of N,N'-bis(3-dimethylaminopropyl)dithio-oxamide have been characterized in terms of color, effect of pH, rate of color formation, structure in solution, order of addition of reagents, adherence to Beer's law, and sensitivity. The reactivity of the reagent to other ions has been reported. A method for the simultaneous spectrophotometric determination of cobalt, nickel and copper has been developed. The results of the application of this procedure to synthetic samples and to several National Bureau of Standards samples are given.

The Keeney-Bassette method for determining hydroxymethylfurfural (HMF) content of whole milk powder was studied. The variables examined were: solids of milk, age of reagents, and method of sample preparation. Results indicate that total HMF color is a function of the solids content of milk with high solids yielding more color. A seasonal variation in HMF color, as well as a daily variation within each season, also was observed. This source of error was eliminated by establishing a blank value for each new lot of milk processed. A second type of time-oriented variation in HMF color formation was observed. For a given powder the HMF value gradually increased as the oxalic acid aged. It is concluded that the method is satisfactory for measuring HMF and HMF precursors in processed milk, provided the solids content of the milk is kept constant, a raw milk blank is established for each milk, and oxalic acid is prepared fresh daily.

A colorimetric method has been developed for the routine determination of estrogens in pharmaceutical preparations. The method is based on the formation of an azo dye from the condensation of diazotized 4-amino-6-chloro- m -benzene disulfonamide with estrogens which contain a phenolic hydroxyl group. The condensation product exhibits a red color with an absorption maximum at 500 m μ in alkaline solution. The most reproducible results are obtained when coupling is carried out at pH 5 buffered solution. The color formation obeys Beer's law over a range of 0.05–0.25 mg. of estrogens per ml. of sample solution. Optimum conditions for the color formation have been determined, and the application of this procedure to pharmaceutical products is given.

Procedures have been described for the sequential determination of copper and iron in one aliquot of a trichloroacetic acid-ascorbic acid filtrate followed by the determination of zinc in a second aliquot. Alternatively, copper, iron, and zinc can be determined individually on three aliquots of the same solution or either can be determined separately on a smaller sample. All reactions are selective for the three metals under the described conditions. The various parameters of the procedure are shown to be optimum for color formation and without interference or interaction for any metal by either of the other two metals.

A number of methods for determining the identity and concentration of the oxidants produced photochemically in model systems are presented. The application of these methods to atmospheric sampling is discussed. The effects of the following variables are considered: spectral characteristics of the reagent blends and the colored species in question; temperature; order of addition, color stablity and rate of color formation; reagent concentrations; hydrogen ion concentration (pH); and various determinate errors. Calibration curves, molar absorptivities, and interferences are presented in detail.

Irregularities encountered in the application of the Liebermann-Burchard reaction to the determination of cholesterol, isocholesterol and their esters in wool fat unsaponifiables and wool fat have been investigated. Times and temperatures of color formation have been found critical in the determination of absorptivities and their analytical application. A satisfactory analytical procedure has been developed.

The assays of N -acetylneuraminic acid by the thiobarbituric acid, resorcinol, and direct Ehrlich methods were investigated comparatively by a statistical examination, in order to study the factors influencing color formation. Interference with color formation in the assay with the thiobarbituric acid method was similar to that with the direct Ehrlich method, and different from that with the resorcinol method.

Iodide ions react with thallic ions at pH 2–8 to form a complex iodide, which is suitable for the spectrophotometric determination of thallium. The reaction has a sensitivity of 0.05 μg Tl per cm2 for log I 0 I = 0.001 and obeys Beer's law up to 40 p.p.m. Optimum conditions for the reaction have been established. The standard deviation is 0.6%. The effects of temperature and pH, the ratio of thallium to reagent, stability of the complex, its conformity to Beer's law, and the rate of color formation were studied. The effect of many diverse ions was examined.

Summary A colored complex formed by the condensation of the oxy-acids of molybdenum (VI) and vanadium (V) in a 5 to 1 ratio is used as the basis for a spectrophotometric method for vanadium. The absorbance of the intense yellow complex is measured at 360 mμ. The color is stable for at least 24 h and follows Beer's law over the concentration range of 2·10−5 to 6·10−4M vanadium. A standard deviation of 0.056% in steel samples containing 2.04% vanadium was obtained for five determinations. Factors affecting the color formation and the analytical applications to the determination of vanadium are presented.

The diazotization product of 4-amino-6-chloro-m-benzenedisulfonamide has been found to be a useful reagent for the colorimetric determination of a vitamin, steroid, and alkaloid. A general method, with slight modification, can be applied to those compounds which contain a phenolic or similar-to-phenolic hydroxyl group. Pyridoxine hydrochloride, 17β-hydroxy-7aα-17α-dimethyl-B-homo-A-norestrane-3,6-dione, and morphine sulfate were used as coupling components in this study. The optimum reaction conditions for coupling and color formation have been determined and the applicability of the method in the presence of commonly used ingredients is demonstrated.

Various amounts of practically all of the chromatic elements in the periodic system were introduced individually into a simple lead silicate glaze, and the resulting glazes were analyzed for color with an automatically recording photoelectric color analyzer. The spectrophotometric data were then converted into trichromatic and monochromatic specifications of color. An empirical relationship was then determined between the concentration of the chromatic element and the three attributes of color: hue, saturation, and brilliance. The effect of glaze thickness on color was also studied. It was found that the same laws connecting concentration of the coloring element with the three attributes of color held for all the elements used. A number of elements not previously mentioned in the literature as color-producing agents were found to give interesting colored glazes. In several cases an element was added to the base glaze in various forms, such as nitrates, chlorides, and oxides. If equivalent amounts were added, the color in all cases was the same regardless of the colorless radical.

During the burning of silica refractories, spots or areas of dark cream to a reddish-brown color may develop in some of the brick or shapes. This is often called mottling, and its occurrence during the manufacture of the product cannot be definitely controlled. Questions occasionally arise as to whether the colored brick are of as good quality as the uniformly cream-colored brick. No records are available to show or indicate that color as such has been a cause of shorter life or failure in service. Data are presented that were obtained from testing the mottled and light-colored brick, and these show that there is no practical difference between them; consequently, color alone should not be a criterion for judging quality. The traces of iron present in the silica used are a necessary constituent in the formation of the color. The light-colored product, however, contains the same quantity of iron. It is not entirely clear as to how the iron is present in the two types. Unknown conditions during manufacture are such that the traces of iron may be influenced to form either the light or mottled brick, but the process cannot be controlled. A considerable amount of experimental work is presented which shows the nature of the color behavior with comments on certain conditions that cause the color formation.

Nucleic acids (RNA and DNA) can be separated from extraneous materials by precipitation as their cadmium salts. This separation substantially improves the reliability of subsequent determinations of RNA by the orcinol method and of DNA by the diphenylamine method. In addition, color formation in the orcinol reaction is stabilized by addition of n-butanol to the reaction mixture, thereby improving the precision of the method.

A procedure for the colorimetric determination of molybdenum with disodium-1, 2-dihydroxybenzene-3,5-disulfonate (Tiron) has been presented. The maximum absorbancy of the yellow colored complex is at 390 mμ the optimum pH range is 6.6-7.5; and the Tiron concentration is 1.5-2%. The color reaction conforms to Beer's law and has a practical sensitivity of 0.1 p.p.m. molybdenum. The color formation is instantaneous and stable for at least three weeks. There is no temperature effect over the range of 15° — 40° C. The tolerances of the colored complex to many diverse ions have been established. The separation of molybdenum from interfering ions is accomplished by precipitation of the former with α-benzoinoxime. Molybdenum and tungsten are separated photometrically. The colorimetric determination of molybdenum with Tiron was successfully applied to a variety of steels and other materials.

低乾クレゾール1 号は自然着色著しく, また異臭を有す。低乾クレゾール1 号は1.350 vol% の不純物を含有している。この不純物が製品の品質低下の原因をなすと思われるから,不純物を究明し,その除去法を製造過程に応用し,製品の品質向上をはかることを目的として,この実験を行った。タール酸品質低下の原因として, 今日まで安息香酸, インデン, 酢酸, ギ酸, ピロール, カテコール等色々の不純物があげられている。低乾クレゾール1 号中にも, その自然着色, 異臭の原因をなす不純物として, これらの存在が予想される。これらはいずれも低乾クレゾール1 号については, 低沸点留分, 高沸点留分中に, また不純物は塩基性油, 中性油, 強酸性油中に存在するものと思われる。本報告は低乾クレゾール1 号の品質低下の原因をなす不純物, 特に自然着色に影響をおよぼす不純物が, 果して予想されるとおり,低沸点留分,高沸点留分中に,また塩基性油,中性油,強酸性油中に存在するかを知るために行った実験である。その結果, 予想どおりの結果をえたので, 低乾クレゾール1 号の低沸点留分, 高沸点留分中の不純物をしらべ, 2-,3-,4-メチルピリジン,2,3-,2,4-,2,6-ジメチルピリジン,o-オキシベンズアルデヒド,ベンズアルデヒド,4-メチルシクロヘキサノン, アセトフェノン, ナフタリン, n- 酪酸, n- 吉草酸, カテコール等の存在を確認した。

Problem of mental and physical hazards resulting from discoloration of streams by dye wastes; pertinent theories of color formation; part chemical structure plays; possibilities of technique whereby color of typical azo dye was altered by utilizing methods based on theoretical consideration of dye's chemical structure; reduction with SnCl 2 and salting with NaCl were most effective in reducing and changing color of methyl orange, monoazo dye.

SUMMARY Isolation and purification is reported of a polyphenol that contributes to the color formation in the processed dark olive, known in commerce as the California ripe olive. This compound (probably oleuropein as described by Cruess) was purified by counter-current distribution. Acid hydrolysis yielded glucose and a second unreported sugar, arabinose. Additional evidence indicates that the compound is not a double ester of glucose, as previously reported.

The physical and chemical properties of bleach-ing clay are presented, and the effects of these properties upon its performance in bleaching. Various bleaching effects are described: 1) Comparison of atomspheric vs. vacuum bleaching, showing the superiority of one or the other depends upon the predominance of oxidative color fading or color fixation/ color formation in the atmospheric bleach. 2) The log-log bleach curve of clays carried out to extreme dosage. 3) Bleaching time-temp effects on different oils, showing that up to a given time, high temp bleaching gives a lighter color than low temp ; however, with increased time the high temp bleached oil darkens rapidly in con-trast to the low temp oil, which levels out with time. 4) The effect of adding clay to hot oil vs. ad-ding it to “cold” oil, indicating a better bleach when the clay is added to the cold oil, with an explanation for the effect. 5) Comparison of bleaching by filtration of the oil through a layer of clay against conventional bleaching, indicating superior-ity for the former.

In experiments on the storage and processing of fruits it is often desirable to compare the oxidase activity of various specimens. The usual gasometric methods of estimating oxidase activity involve the use of rather complicated and cumbersome equipment and limit the observer to the examination of very few samples at a time. The colorimetric method is simpler and permits observations to be made on rather a large number of samples simultaneously. Guaiac tincture has generally been used for plant oxidase but is not very suitable for quantitative comparisons because of the extreme rapidity of color formation and the evanescence of the color formed by oxidation. Benzidine is somewhat better, but is also apt to lose color rapidly after the maximum depth of color is reached. Filtered apricot juice expressed from ground fresh apricot pulp stored at o-io? F. was adjusted to the pH values given in table i. Readings were taken on the various samples at several intervals. Those taken at i8 hours appeared to give the most concordant results and are presented in the table. In all readings the dye or iodine comparator solution was taken as ioo, the results being expressed as reciprocal of the colorimeter readings

The formation of a 1:1 copper chelate with sodium alizarin-3-sulfonate, having λmax at 500 mμ has been reported. The color formation has been applied to the colorimetric determination of copper on a micro-scale. The color has been found to be stable between pH 3.20 and 7.50, at temperatures 20∼30°C. The sensitivity of the reagent is 6.4 p.p.m. of the copper ion. The interference by a large number of cations and anions has been studied and the tolerance limits are quantitatively determined spectrophotometrically. It has been recommended that the reagent is suitable for the colorimetric determination of copper(II) on a micro-scale and the conditions have been prescribed.

The Prepration of two uracil derivatives of alanine, DL-β-(5-uracilyl)alanine and DL-β(6-uracilyl)alanine, are reported. A structural analog, dl-4,6-dihydroxy-β-(2-(pyrimidinyl)alanine, which was reported to be labile to acid hydrolysis, has now been successfully prepared in our laboratories. The relationship between the relative position of an alanine moity on some nitrogen hetrocyclic ring systems and their color formation with ninhydrin are discussed.

The rates of reaction at 27° 37°, 47°, and 57°, of 17-ketosteroids (17-KS), dehydroisoandrosterone (DHA), and 17-ketogenic steroids (17-KGS) were studied by a modified Zimmermann color reaction. Curves were constructed by plotting absorbance against time necessary for maximum color development at these temperatures. Pooled eluates of 17-KS and 17-KGS from normal urine samples were used in the determinations. Temperature was plotted against the time found necessary for maximum color development using DHA as standard. Experimental results conformed to the temperature-dependence theory of reaction rates, that for every 10° rise, the rate of reaction doubles. Curves of the absorbances at various times of incubation were calculated as percentiles of maximum color formation at each temperature. The interrelationship between 17-KS, 17-KGS, and DHA with respect to optimum reading time was noted. The significance of the finding that the rate of reaction of 17-KGS is much greater than that of 17-KS and DHA is demonstrated. Functional group contribution to the rate of reaction is discussed, as are other factors affecting the Zimmermann color reaction.

Canola and soybean oils both regular and with modified fatty acid compositions by genetic modifications and hydrogenation were compared for frying performance. The frying was conducted at 185 ± 5 °C for up to 12 days where French fries, battered chicken and fish sticks were fried in succession. Modified canola oils, with reduced levels of linolenic acid, accumulated significantly lower amounts of polar components compared to the other tested oils. Canola oils generally displayed lower amounts of oligomers in their polar fraction. Higher rates of free fatty acids formation were observed for the hydrogenated oils compared to the other oils, with canola frying shortening showing the highest amount at the end of the frying period. The half-life of tocopherols for both regular and modified soybean oils was 1–2 days compared to 6 days observed for high-oleic low-linolenic canola oil. The highest anisidine values were observed for soybean oil with the maximum reached on the 10th day of frying. Canola and soybean frying shortenings exhibited a faster rate of color formation at any of the frying times. The high-oleic low-linolenic canola oil exhibited the greatest frying stability as assessed by polar components, oligomers and non-volatile carbonyl components formation. Moreover, food fried in the high-oleic low-linolenic canola oil obtained the best scores in the sensory acceptance assessment.

The ternary complex chromium-peroxo-PAR exhibits an apparent molar absorptivity of 6280 l mol−1 cm−1 when extracted into ethyl acetate from 0.1 M sulfuric acid solution. Beer's law is followed for solutions containing up to 6.0 μg Cr ml−1. Conditions for optimum color formation, complex composition, effects of diverse ions, and application to the determination of chromium in steels are described.

Color of tortillas prepared from grain of 38 sorghum cultivars by a laboratory procedure varied, from a light yellowish to dark-greenish brown. The cooking time and grinding properties of sorghum were affected by kernel size, texture, and structure. Corneous sorghum kernels required longer cooking time than soft, floury kernels. Native sorghums of Honduras and Guatemala with white or colorless pericarp without a testa gave the lightest color tortillas, and had the best overall potential for use in tortilla production. Considerable variation exists among white sorghums. Brown sorghums as expected, produced unacceptable brown-green tortillas with poor taste. Red sorghums, produced tortillas with a dark, unacceptable color. A simple alkali test using five kernels was used to screen white seeded sorghums from the world collection for alkali color formation. Good correlation between the alkali test and tortilla color was obtained. The test is useful in breeding programs to select sorghum with improved potential for use in tortillas and other high pH products.

After modifying the Prescott-Jones colorimetric method for carbamoyl compound determination, it was possible to measure the concentration of N -carbamoyl-β-alanine (β-ureidopropionate) with little interference from its metabolic precursor, dihydrouracil. Color formation at 70°C was linear with respect to N -carbamoyl-β-alanine up to a concentration of 0.07 m m .

A colorimetric assay has been developed for the routine determination of chlorobutanol in parenteral drug preparations. The method is based on the formation of a colored complex between ferric ion and the hydroxamic acid derivative of chlorobutanol resulting from the reaction of chlorobutanol with hydroxylamine in alkaline solution. The color formation obeys Beer's law over the range of 0.1 to 0.8 mg. of chlorobutanol per ml. of sample solution. Optimum conditions for the color formation have been determined and interferences are discussed.

SUMMARY– Pairs of hams from 72 crossbred barrows slaughtered at three weight intervals (68.2, 90.9, and 113.6 kg) were assigned to three treatments of glucono delta lactone (GDL) (0, 30, or 60 g/l) and two post cure aging periods (1 or 14 days). Following post cure aging, samples from the boneless hams were exposed to light (200 ft-c) for various time intervals (0, 30, 60, 90, 120, 150, 180, and 1440 min) and nitric oxide- and total-pigments extracted with acetone/water and acetone/acid respectively. There were no significant differences in color formation or color stability of hams aged 1 or 14 days. The influence of GDL on nitric oxide- and total-pigment formation and stability was nonsignificant at most exposure intervals. Chemical analysis showed a significant decrease in moisture content of hams with increasing amounts of GDL added. Fat, chloride, and ash levels were not different for the three GDL treatments. Residual nitrite levels were found to be significantly lower for the 30 g/l of GDL in hams extracted one day post cure.

The presence of borate in Dische's carbazole reaction increases the color obtained with certain uronic acids. Borate modifies the formation of intermediates during heating with sulfuric acid but does not affect the step of color formation with carbazole.

1. A study has been made of factors causing blue colors in antioxidant treated lards. 2. The formation of blue-colored lards or of blue-black sludges in lard storage tanks is due to reaction of propyl gallate in the antioxidant with iron contamination in the lard. 3. The solubility of the antioxidant mixture in lard is not a factor in the formation of blue-colored lard. 4. A new cause of blue-colored lard has been discovered. This is a photoactivated blue color resulting from irradiation of antioxidant treated lard. The blue color was developed in lard treated with BHA, propyl gallate, and citric acid only when lecithin was present and the lard was contaminated with iron. The state of oxidation of the lard did not contribute to these colors.

On the first blue light symposium held at Marburg in 1979 Eger-Hummel reported on several mutant types of P. ostreatus which are blocked at different stages of sporophore development and then reveal orange or yellow colorations [4]. A relation between color formation and photomorphogenesis in this mushroom was assumed. This paper describes investigations on the conditions for production and on the isolation of the respective pigments.

A generally applicable, inexpensive, and sensitive method for the determination of inorganic pyrophosphate ( PP i ) was developed. PP i was quantitatively separable from solution even in nanomolar concentrations by filtration through a membrane filter in the presence of CaCl 2 and KF. The separated PP i was dissolved by immersing the filter in 0.5 n H 2 SO 4 . Inorganic phosphate ( P i ) was removed by precipitating it as a phosphomolybdate-triethylamine complex and the PP i was measured as a green pyrophosphomolybdate in the presence of 2-mercaptoethanol. Nucleotides and phosphate esters do not react. PP i can be accurately assayed even when there is a 10 4 -fold excess of P i . Trimetaphosphate, tripolyphosphate, and tetrapolyphosphate also give this green color, but the rate of the color formation is 50 times slower than that with PP i . Thus this interference of the polyphosphates can be eliminated or the polyphosphates can be assayed simultaneously with the PP i in the same sample.

Reaction rate studies were carried out on various quality control specimens using a ferrozine iron determination kit. The time required for complete color formation differed among the various materials tested. Quality control materials of bovine origin required a much longer incubation time for full color formation. Using a fixed incubation procedure, the bovine controls would give a falsely low result. The present study suggests that caution is indicated when quality control data using bovine materials are interpreted.

We have developed an indicator plate that works well for diverse types of substrates and microorganisms. The plates are inexpensive and easy to prepare. The essential components are agar, buffer, growth-supporting nutrients, a test substrate, and 2,3,5-triphenyl tetrazolium chloride (TTC). Using various strains of Salmonella typhimurium and Escherichia coli, we have studied and defined the contribution of each component to the satisfactory function of the plate. Colonies capable of catabolizing the test substrate reduce TTC and produce a deep red formazan, whereas colonies failing to catabolize the substrate remain uncoloured. Those with intermediate rates of catabolism differ in rate and/or extent of color formation. In all cases the color is stable because TTC reduction is essentially irreversible. Since the mode of action of these plates is fairly well understood, alternative formulations can be devised to meet specific needs. The general applicability of this TTC indicator system makes it an extremely useful tool in microbial genetics, metabolism, and taxonomy.

Addition of microgram quantities (5–10 μg per 2 ml) of Mn2+, Fe2+, and Mo2+ increases the intensity of color developed by amino acids two- to three-fold when reacting with ninhydrin. The lowest limit detected by the increased sensitivity of the reaction is 3 nmol of an amino acid. Cd2+, Zn2+, and Al3+ depress the color formation due to reaction between amino acids and ninhydrin. When chromatograms of amino acids are first sprayed with aqueous manganese chloride and later with ninhydrin or with ninhydrin solution containing manganese, not only is the sensitivity increased, but the stained spots retain their color for longer periods.

Disodium ethylenediaminetetraacetate (EDTA) 0.005 per cent successfully inhibits color formation in parenteral papaverine hydrochloride solutions.

The lack of specificity observed in the serum chemical studies with the DPA and "no DPA" reagents is indicative of the limitations in the general applicability of these tests; however, although these studies do indicate the potential that exists for variation or enhancement of the DPA or "no DPA" indices, there is no evidence that such color-forming components are observed in serum. The statistical results obtained with the DPA and "no DPA" reagents reported in our clinical findings reveal a definite parallel between these 2 tests, indicative or suggestive of measurements of similar materials, if not the same substance. In addition, the apparent chemical specificity of the "no DPA" test for neuraminic acid caused us to reconsider the possibility that it is the material in serum responsible for color formation. Under these circumstances, the apparent lack of specificity of the DPA and "no DPA" tests, or both, would be academic in nature for all practical purposes. In other words, in the absence of DPA or "no DPA"-sensitive carbohydrates, other than neuraminic acids, one can equate the results obtained with these reagents with the apparent content of serum neuraminic acid. Neuraminic acid, according to the nomenclature of Blix and associates, refers to a hypothetic amino sugar that occurs in nature as N-acetyl and O-acetyl derivatives