Reagent Grade Chemicals Research Articles

Structural and electronic properties of three aqueous-deposited films: CdS, CdO, ZnO, for semiconductor and photovoltaic applications

This study shows that CdS. CdO and ZnO films can be deposited on glass, aluminum, copper, nickel, molybdenum, steel, tin and zinc substrates from aqueous solution using reagent grade chemicals. Their structural properties were investigated and these values found compared well with values for the bulk form showing that equilibrium phase was being deposited. The properties of solar cells prepared from multiply deposited CdS films are reported. A short-circuit current of 2.7 mA and an open-circuit voltage of 0.2 V was obtained for the best cell under an illumination of AM-1 and an area of 1 cm 2. The characteristic curve is a straight line showing that improvements could possibly be made in these devices to obtain greater efficiencies. The best cell was measured in the sun at an efficiency of 0.13%. The solution method offers an intriguing and inexpensive possibility for the deposition of semiconducting films.

The Use of Raman Spectroscopy for the Quantitative Analysis of Impurities: Sulfate in NaNO3

Oxyanion impurities in reagent grade chemicals may be detected and measured by Raman spectrophotometry. During recent studies of NaNO3, samples were prepared from a bottle of certified reagent grade chemical. A weak band at 981 cm−1 was detected in the Raman spectrum when high sensitivity was employed—conditions that cause the 1051 cm−1 line of NO3− to be much off scale (Fig. 1). The origin of the 981 cm−1 band was traced to SO42− impurity, listed by the manufacturer as 0.002 wt %. Phosphate ion also contributes intensity in this spectral region, but its molar intensity is considerably less than that of the symmetric stretch of sulfate, and interference in this case was not considered significant.

Electric Conduction and Dielectric Properties of Bi<sub>2</sub>O<sub>3</sub>-B<sub>2</sub>O<sub>3</sub> Glasses

Electric conduction and dielectric properties of the bismuth borate glasses were determined over the entire region of homogeneous glass formation (31-80 Bi2O3mol%). The electric conduction is affected by water in the glass. The glasses containing the least amount of water could be obtained when reagent grade chemicals of Bi2O3 and B2O3 were melted in the vacuum furnace.The results on the electric conduction are summarized as follows:1) The temperature dependence of conduction was given bye=e0exp(-ΔHdc/kT)in which e is conductivity, ΔHdc activation energy of conduction, T absolute temperature, k Boltzman's constant and e0 constant. The activation energies increased from 1.12eV (80Bi2O3mol%) to 1.59eV (31mol%). The values of e0 were about 103ohm-1cm-1.2) The dielectric rlaxations with very long relaxation time were observed and the relaxation frequency was given byfm=fm0exp(-ΔHac/kT)in which ΔHac is activation energy of relaxation and fm0 constant. The values of fm0 were about 1013Hz. The following correlations were obtained between the conduction and the dielectric relaxation, ΔHdc≅ΔHace≅2πe0Δefmin which e0 is dielectric constant of free space and Δe magnitude of the dielectric dispersion.3) The conductivity decreased as the pressure increased and the frequency of dielectric relaxation was shifted to lower frequency side.The obtained values of ΔHdc, e0, ΔHac and fm0 were compared with those of the glasses of three different types (alkali oxide glasses, transition metal-containing oxide glasses and chalcogenide glasses). And it was found that those values of bismuth borate glasses were agreed very well with those of the alkali oxide glasses. As described in 3), the conductivity decreased as the pressure increased. The investigations on the pressure dependence of conduction show that the conductivity of alkali oxide glasses decreases by applying pressure, while that of electronic conducting glasses increases. From the facts described above, we concluded that the conduction mechanism of bismuth borate glasses is ionic. From the composition dependence of conductivity and the calculated values of carrier concentration from Δe, the conduction mechanism was ascribed to Bi3+ ion migration and not to proton or a trace of alkali ion migration.On the basis of the experimental results on dielectric properties the following problems were discussed, 1) polarization mechanism, 2) electronic polarizability of Bi3+ ion and 3) the temperature dependence of dielectric constant.

Flame Emission Analysis of Potassium Contamination in Silicon Slice Processing

A study of potassium contamination in semiconductor processing was undertaken to determine its extent and magnitude in processing chemicals and slice‐handling tools. Simple methods of preventing contamination of silicon and silicon dioxide from chemicals and tools were investigated. To this end a flame photometric technique has been developed to detect routinely less than one part per billion (ppb) of potassium in solution. Potassium contamination of reagent grade chemicals commonly used in silicon device processing is generally less than 500 ppb which is comparable to levels of sodium contamination. However, Triton X‐100 surfactant solution and 30% hydrogen peroxide contain several orders of magnitude more sodium than potassium. Pyrex dishware yields minimal amounts of potassium whereas significant amounts of sodium are leached from Pyrex by chemicals. It is shown that potassium levels on both bare and oxidized silicon slice surfaces from a basic or acidic treatment can be reduced to overflow rinse of deionized water and by using slice‐handling tools and spin drier surfaces which have been rinsed with deionized water for short times immediately prior to use. Potassium is shown to be mobile at high temperatures and presents the same unwanted electrical instability in silicon dioxide as does sodium.

High-magnesia Portland cements: studies on cements prepared with reagent-grade chemicals

Synopsis Several Portland cement clinkers containing up to 15% MgO have been prepared with reagent-grade chemicals, and the properties of cements made from them have been investigated. In particular, the effect of variations in composition, burning temperature and cooling conditions of the clinkers upon the autoclave expansion and strength of the corresponding cements has been examined in detail. It is not possible by controlling these factors alone to produce ‘sound’ (i.e. volume-stable) Portland cements having MgO percentages much above the present limits recommended by the Standards in different countries. The addition of a suitable reactive silicate material in finely divided form, e.g. pulverized-fuel ash, effectively stabilizes high-magnesia cements and these mixtures pass the ASTM test for soundness of Portland cements. Data on the autoclave expansion and mechanical strength of these mixtures of high-magnesia cement and pfa are presented.

Mass spectrometry of volatile mercury salts

The integrated ion current method is applied to the determination of μg quantities of mercury(II) chloride. The mass spectra of both mercury(I) and (II) chlorides indicate that the analytical reagent grade chemicals contain traces of mercury(II) bromide and iodide.

Induced hemorrhagic hypotension. Its effect on plasma 5-hydroxytryptamine and plasma 5-hydroxyindole acetic acid levels.

The effect of hemorrhagic hypotension on plasma serotonin levels has been investigated previously,^1,2but it remains to be shown conclusively whether or not the level of this biogenic amine rises, falls, or remains constant as a result of hypotension. Since serotonin (5-HT) is rapidly metabolized to 5-hydroxyindole acetic acid (5-HIAA), changes in plasma 5-HT are reflected by changes in the plasma 5-HIAA levels.^3,4In the present study, simultaneous determinations of plasma 5-HT and of plasma 5-HIAA, the predominant end-product of 5-HT metabolism, are made at specific intervals before and during hypotension induced by hemorrhage in an attempt to contribute further information on this subject. <h3>Methods and Materials</h3> Reagent grade chemicals and solvents were used in the serotonin determinations made by a method modified from Waalkes.⁵These included the following: (1) NaCl; (2)<i>n</i>-butyl alcohol; (3)<i>n</i>-heptane (commercial<i>n</i>-heptane washed with equal volumes of 0.1

Rapid and sensitive method for determination of catecholamines in human plasma

Various methods1-4 using trihydroxyindol reaction for the measurement of catecholamines in human plasma have been designed by workers hitherto. However, in these methods1, 3, 4, isolation of the catecholamines with an adsorbent presents considerable difficulties. Thus, in spite of the availability of these methods1, 3, 4 reproduction by other laboratories are difficult. The main objective of the present work was to improve the method for simultaneous determination of epinephrine (Ep.) and norepinephrine (NE.) in human plasma. A preliminary experiment was set up in order to run a comparison against these methods with respect to the recovery, accuracy and rapidity. Of these methods PRICE's method3 showed satisfactory recovery and rapidity. Thus several improvements of PRICE's methods3 were made: 1) Purification of acid-washed aluminum oxide (Merck acid washed #71695) was made. 2) A large amount of EDTA disodium was used in several steps. 3) The timing procedure becomes essential due to the fact that fluorophor of both Ep. and to a smaller degree NE. decays at a considerable rate. Thus, a means with sufficiently high accuracy and rapidity was obtained. Material and Method A preparation of acid-washed aluminum oxide (for chromatographic use). a) 300-500 g of alumina (Merck-71695 acid washed) was boiled using a reflux condenser with frequent shaking in 1 L 2N HCl for 1 hour. The slurry was allowed to cool to room temperature. This was transferred to a 1 L chromato-graphic tube with a fritter disc (pyrex #38450). and was cycled with deionized water until the pH of the supernatant rose to 5.0 after which a stirring of the column was followed by cleaning of the supernatant for 2 minutes. This rapid cleaning indicates that most of the fine grain alumina is removed. Next collect the alumina in a suction funnel with filter paper, allow to dry overnight on large sheet of filter paper (Whatman No.3) at room temperature. Then heat in an oven at 200°C for two hours, place in desiccator. b) All solutions of mineral acids, bases, and buffers were prepared from reagent grade chemicals with water previously distilled and passed through a commercial deionizer. Water purified in this manner is used throughout the procedure.

Virus Inactivation in Water‐Softening Precipitation Processes

The principal objective of this research was to determine the nature and extent of the effect of water‐softening precipitation processes on bacterial viruses. The virus used in this study was the T2 bacteriophage. Esch. coli, strain B, was used in a pure culture as the host bacterium for quantitative determinations of the virus concentration. Stock solutions of coagulants were prepared from reagent grade chemicals. Synthetic water samples, containing known amounts of calcium, magnesium, alkalinity, carbon dioxide, and total hardness in the range of 100‐500 mg/l were prepared and placed in each of five 2,000‐ml reaction beakers. A sixth beaker, containing the same volume of distilled water adjusted to pH 7.0 with a hydrated lime solution, served as a control. The six beakers were placed under a standard jar test machine with a variable‐speed mixer. Appropriate volumes of stock bacteriophage suspension were diluted and added to each of the beakers. Immediately after the initiation of rapid mixing (100 rpm), the required amounts of softening chemicals were added, and rapid mixing was continued for one minute after addition of the chemicals.

Effect of Imbalance of Boron Nutrition on the Peanut1

AbstractThe ‘Florigiant’ variety of peanut (Arachis hypogaea L.) was grown 2 years in pot cultures on Lakeland fine sand, a soil deficient in boron, to determine the effects of imbalanced boron nutrition on peanuts. Variations in fertilization were: no treatment, complete fertilizer and lime treatment including the micronutrients, and the same as the latter except without boron. The containers were low‐boron and each held 60 pounds of soil. Reagent grade chemicals and distilled water, which was then passed through an ion exchange demineralizer, were used throughout the experiments. Flower counts, yields of shoots, roots and fruit and quality studies on the fruit were used to determine the effects of imbalanced boron nutrition. Without boron in the fertilizer, shoots were stubby, leaves frequently were mottled, dark areas appeared at the internodes of the branches, and stems sometimes cracked. Roots were also stubby and yields of fruit negligible. In contrast, plants with boron in the fertilizer were free of these abnormalities and produced many peanuts. With boron in the fertilizer, peak flower production came early in the flowering period, while without boron more flowers were produced but the distribution pattern was changed. With no treatment the plants were small, appeared normal, and yielded more peanuts of a better quality than plants with complete fertilization minus boron.

Volatilization Loss of Sodium Borosilicate Ternary Glasses

Volatilization of glass components and formation of inhomogeneity in a glass melt during heating often result in striae, devitrification or fracture of the final glass products. Borosilicate glasses were known of their relatively high volatility at the temperatures of melting.Volatilization loss at 1410°C was measured by thermo-balance method on the ternary Na2O-B2O3-SiO2 glasses in the composition range of 0-40 Na2O, 0-40 B2O3 and 60-85 SiO2 in wt%. The glass batches were prepared using purified sand and reagent grade chemicals and were melted in a platinum crucible in electric or gas-fired furnace. For the weight loss measurements, the glasses were held in small platinum crucible suspended in a vertical electric furnace. Results were as follows:1) The amont of volatilization loss in a fixed time (for example, 1 or 6hr) and with fixed Na2O/B2O3 ratio decreased with increase of the SiO2 content, and for the constant SiO2 content the loss had its maximum at Na2O/B2O3 ratio slightly lower than 1. At these maxima, the losses were far greater than those of the corresponding Na2O- or B2O3-SiO2 binary glasses.2) In almost all the glasses, the loss increased linearly with time. at the initial periods of heating. Generally, however, volatilization rates decreased with time.3) Especially in glasses containing larger than 75wt% SiO2, crystallized surface layeres were formed in the course of the measurement, and in consequence, the volatilization rates decreased distinctly.4) Under the condition of the measurements, thermal convection was observed in the crucible. Contrary to the case of glasses with relatively high SiO2 contents, in glasses with low SiO2 contents thermal convection took place distinctly that the considerable mixing phenomenon was observed in the glass melts.5) One of the possible mechanisms which explain the results described in 1) and 2) is given in the following: At the initial periods of heating, volatilization rate is controlled by the evaporation of the volatile components from the melt to the atmosphere or by the flowing away of the gas atmosphere near the surface of the melt. Then, diffusion controlled mechanism or the effect of the lowering of the concentration of the volatile components in the melt gradually predominates, and lowers the volatilization rate.6) Quatitatively, the relation between composition an volatilization loss showed a good agreement with the results of kolykov measuring at 1200°C (ref. 5). Quantitatively, however, the loss was 10-100 times larger than those by kolykov owing to the differences of the mesuring temperatures. Under the assumption that the initial volatilization rate is proportionate to the vapour pressure of glasses, it could be inferred that phase separation in the glass melts occur in the composition range with relatively low Na2O contents.

Permeability Reduction Through Changes in pH and Salinity

Abstract Formation damage, i.e., reduction in permeability, has been generally attributed to clay minerals which expand or disperse upon contact with water that is less saline than the connate water. Laboratory studies show that permeability reduction can also occur in formations containing only nonexpandable clays, such as illite or kaolinite, and can be caused also by changes in pH. Furthermore, pH changes can damage even formations that are essentially free of clay. It is suggested that permeability reduction is due to the small passages being blocked by particles, which may be dispersed clays, cementation material or other fine particles. These particles are dislodged by dispersion of clays due to changes in salinity or by dissolution of calcareous cement by acids, or of silicaceous cement by alkaline solutions. In working with reservoir cores, it was found that extracted cores damaged more easily and extensively than nonextracted cores. The extent of damage depended also on temperature. Introduction Permeability is an important property of porous media and has been the subject of many studies by engineers and geologists. Many of these studies are concerned with formation damage, i.e., reduction in permeability, resulting from exposure of oil-producing formations to water substantially less saline than the connate water. This effect causes understandable concern since during drilling, completion and production phases formations are often exposed to fresh water. The damage resulting from contact with relatively fresh water bas been attributed to expansion and dispersion of clay minerals. During laboratory investigation of the use of NaOH as a wettability reversal agent to increase oil recovery from oil-wet reservoirs, several cores used in the displacement studies suffered loss in permeability. Despite the traditional usage of NaOH for conditioning aqueous mud systems, the role of the caustic filtrate in wellbore damage seems to have been overlooked. Browning has recently reported on the effects of NaOH in dispersing clay minerals but he was concerned only with complications that may arise in drilling massive shale beds. The following study was made to examine the role of pH and salinity changes in core damage. Where corns from reservoirs were used, tests were performed with extracted and nonextracted cores both at room and reservoir temperatures, since it was felt that the test environment and core condition may affect the results. Because of its limited coverage and exploratory nature, this study is not intended to provide answers to field formation damage problems. It is hoped that it will encourage research into new aspects of the permeability reduction problems, particularly those allied to new recovery and production processes. PROCEDURE In all permeability tests, fluids were pumped through the cores at a constant volumetric rate. Only deaerated fluids and reagent grade chemicals were used. The fluids were passed through two ultrafine filters before injection to remove any entrained particles. The cores, with the exception of the unconsolidated cores, were mounted in Hassler holders. Water was used to transmit pressure to the sleeve. The inlet endpiece had two entry ports which permitted scavenging one fluid with another to avoid any mixing in the small holdup volume. The cores were flushed with CO2 gas, evacuated for 5 to 6 hours and saturated with the first liquid at a pressure of 1,000 psi for 24 hours to eliminate any free gas from the cores. Pressure differences up to 20 psi were measured by transducers, calibrated in inches of water and continuously recorded. For greater pressure drops, gauges were used. All reservoir cores were cleaned with a light refined mineral oil, then with heptane, and finally dried with CO2. Compatibility tests showed that no precipitates formed when mineral oil and the crudes were mixed. Some cores were extracted in Dean-Stark-type solvent extractors using xylene and trichloroethane and dried in a vacuum oven at 450F.Each test consisted of a sequence of water, test solution, and again water flow. RESULTS AND DISCUSSION STUDIES IN BEREA CORES Salinity Contrast Berea cores 2-in. in diameter and 12-in. long were cut from sandstone quarried in Cleveland, Ohio. The clay minerals were identified by X-ray diffraction to be chlorite, kaolinite, illite and interlayered illite. Flow of fresh water or 30,000 ppm brine does not cause any permeability reduction (Fig. 1). However, after injection of brine the core is readily damaged by fresh water. Damage starts almost instantly as the fresh water injection is begun, and at a cumulative injection of 1.2 PV fresh water, the permeability has dropped from 190 to 0.9 md. Upon continued injection, the effluent contains clay minerals dislodged from the core. JPT P. 1449ˆ

Quality of Reagents in Micro Iodine Methods

Iodine, present as an impurity, has been found in widely varying amounts in different batches of certain reagent chemicals used in iodine assay methods. Reagents containing iodine impurities cannot be used in sensitive analytical procedures for the determination of trace levels of iodine in biological materials. Methods are described for the estimation of the iodine (or iodine-like) content of reagent grade chemicals. Maximum permissible levels of iodine impurities in chemicals used to prepare reagents for iodine assay methods are specified.

Effect of Solution Trace Impurities on I‐V Characteristics of Electrodeposited Surface Barrier Diodes

Radioisotopes were used to determine the surface concentrations of metallic impurities introduced on mechanically polished Ge surfaces during acid clean‐up etching and jet electrodeposition. Reagent grade chemicals, to which were added radioactive metallic ions in the concentration range below 1 ppm, were used in the experiments. Surface coverage ranged from fractional monolayers in acid etching to several monolayers in jet electrolysis. In jet electrodeposition, autoradiograms revealed that noble metal impurities are chemically plated onto Ge electrodes, the distribution being a function of the hydrodynamic flow pattern, but independent of current density. The strong influence of these metallic impurities on the reverse I‐V characteristics of surface barrier diodes is due to a p‐type channel.

EFFECT OF CHELATING AGENTS ON THE GROWTH OF ESCHERICHIA COLI IN SEAWATER.

Jones, Galen E. (Scripps Institution of Oceanography, University of California, La Jolla). Effect of chelating agents on the growth of Escherichia coli in seawater. J. Bacteriol. 87:483-499. 1964.-Escherichia coli did not grow at 37 C, or grew only after a prolonged lag phase in filter-sterilized basal seawater medium (synthetic or natural seawater supplemented with glucose, NH(4)Cl, and K(2)HPO(4)). When this basal medium was enriched with 0.01% or less organic matter, such as casein hydrolysate, peptone, or yeast extract, growth always occurred after a short lag phase. Adding 10(-5)m cysteine or autoclaving the seawater gave a similar effect. A variety of organic chelating agents (histidine, glycine, methionine, glycylglycine, 8-hydroxyquinoline, thioglycolic acid, o-phenanthroline, disodium ethylenediaminetetraacetic acid, etc.) reversed the toxicity of filter-sterilized basal seawater medium in concentrations predictable from stability constants. Even metal-complexing agents such as Na(2)S(2)O(3), Na(2)S, and NaCN in appropriate concentrations reversed toxicity. The quality of the distilled water and the treatment of glassware had a significant effect on the growth of E. coli in basal seawater medium. It was concluded that iodate is probably not the toxic substance for E. coli in seawater, since relatively high concentrations were stimulatory. The inhibition resulting from the individual salts of synthetic seawater was proportional to their concentration; NaCl was most inhibitory. This toxicity is believed to be derived from trace impurities in the reagent-grade chemicals used to prepare synthetic seawater. Evidence was also found for the toxicity of heavy metals in natural seawater. Heavy metals in seawater appear to inhibit growth but not respiration.

Impurities in analytical reagent grade chemicals

Impurities in analytical reagent grade chemicals

A copper requirement for the sporulation of Bacillus megaterium.

AN important relationship exists between metal ions and bacterial sporulation1,2. In previous mineral studies with spore-formers c.p. or reagent grade chemicals were used, and although important metal associations with sporulation have been revealed the presence and effect of unsuspected trace amounts of metallic ions were not considered.

Magnesium Requirement of the Young Chick Determined with a “Magnesium-Free” Diet

ALMQUIST (1942) concluded that the chick requires 400 p.p.m. of dietary magnesium for optimum growth and survival. Using purified diets, Snyder (1954) and Scott et al. (1956) could not improve chick growth with supplemental levels of magnesium greater than 250 and 100 p.p.m., respectively. Moeller (1959) found the magnesium requirement of the chick to be similar to that suggested by the National Research Council (1954) of 220 mg./lb. of diet. In all studies cited, the basal diets employed contained appreciable amounts of magnesium of unknown availability. Recently, Gardiner et al. (1959) were able to reduce the magnesium content of their glucose-isolated soybean protein basal diet to 75 p.p.m. by using only reagent grade chemicals in the salt mixture. They report that the chicks’ requirement for magnesium, as measured by growth and clinical deficiency symptoms, was of the order of 250 p.p.m.In the present study, a basal diet, essentially free…

Infrared determination of traces of sulfate in reagent chemicals

A method for determining traces of sulfate in reagent-grade chemicals is presented. The sample is passed through an alumina column in acid solution to isolate the sulfate, which is then eluted with ammonia. Potassium bromide is added to an aliquot of the eluate, and the solution is freeze-dried. The resulting powder is pressed into a disk whose infrared spectrum is recorded. The method is reasonably accurate and requires a minimum of operator time per sample because a large number of samples can be processed together

Experimental Production of Magnesium Deficiency in Lambs on a Diet containing Roughage

HYPOMAGNESAEMIC tetany occurs (a) in young ruminants raised exclusively on milk diets and (b) in adult ruminants near the time of parturition, when grazing in certain areas, in the spring and autumn. The latter conditions are difficult to produce experimentally and the causative factor(s) are not well understood. The former type is readily reproduced1–5 but has been done only under conditions which inhibit normal rumen development, that is, the abnormally prolonged feeding of a roughage-free diet. In this communication, we wish to report the experimental production of hypomagnesaemia in lambs, on a roughage-containing diet of composition as given in Table 1 (diet 1). This diet contains only 0.02 per cent (magnesium air-dry basis, but is adequate in other respects. Reagent grade chemicals were used in preparation of the mineral mix and dicalcium phosphate as the calcium source.