1M Hydrochloric Acid Research Articles

Accurate measurement of resistant soil organic matter and its stoichiometry

Research suggests that relatively stable, fine fraction soil organic matter (FF‐SOM) has almost constant concentrations of nitrogen, phosphorus and sulphur (NPS) per unit of carbon (C), although there are considerable differences in the datasets used. Such differences could, in agricultural situations in particular (where inorganic nutrients are often added), result from substantial concentrations of inorganic‐N, inorganic‐Pand inorganic‐Sthat remain in the soil. We assessed the efficacy of removal of inorganic nutrients with different washing procedures (0.1 or 0.5 mhydrochloric acid solution). Even after repeated additions of inorganic‐N, inorganic‐Sand inorganic‐Pto soil as part of a long‐term incubation experiment, washing soil with 0.1 mHClwas effective at removing residual inorganic‐Nand inorganic‐S, but not effective at removing inorganic‐P. We demonstrate that estimates ofC:N,C:SandC:Pratios inFF‐SOMcan be substantially underestimated when these washing procedures are not carried out as part of the soil analyses. This leads to overestimation of the amounts ofN,PandSthat are required for co‐sequestration ofCduring the formation ofFF‐SOM. BecausePis essential for the formation ofFF‐SOM, more research is needed to obtain an accurate measure of thePrequired per unit ofFF‐SOM. Although washing with 0.1 mHClalso removed someFF‐C, we suggest a method to compensate for this. We tested the procedure on soil with clay contents ranging from 8 to 60%; however, the stronger acid might be more suitable for soil with larger clay contents.HighlightsWhat is the best method to measure the size and stoichiometry of the stable soil organic matter pool?Enlarging this soil organic matter pool could help restore fertility and mitigate climate change.Washing soil with dilute acid can remove excess inorganic nutrients, but it also removes organic carbon.We recommend the size of the pool on unwashed soil and the stoichiometry on washed soil is measured.

Heavy Metal Pollution by Atmospheric Transport in Natural Soils from the Northern Part of Eastern Carpathians

The present paper is a study of the heavy metal contamination ofnatural soils due to atmospheric transport in the northern partof Eastern Carpathians. The study area is located north of BaiaMare, the main Romanian centre for processing complex sulphideores. Ten undisturbed soil profiles of andosols and andic soilswere investigated. The distribution of heavy metals (Pb, Cu, Zn,Mn, Ni, Co, Cr and Cd) was studied along the soil profile and atspecific distances from the pollution sources. In addition tothe total nitric acid soluble fraction of the metals, amounts oflead, copper, zinc and manganese extractable with 0.05 Mhydrochloric acid were determined to evaluate the fraction ofeach metal potentially available to plants. Surface soils in theIgnis Mountains (10 km from Baia Mare) were more polluted withlead (200–800 ppm), with the concentration decreasing withdistance from the processing plants. Lower lead concentrationswere observed in the deeper soil horizons. The fraction of leadextractable in 0.05 M hydrochloric acid was generally higher athigh total concentrations of lead. From its geographical andsoil profile distributions it is also evident that cadmium wasalso supplied in appreciable amounts to the topsoil from thesame polution sources, whereas the trend was weaker for zincand chromium and not evident for copper, manganese, nickel, orcobalt. The fraction extractable with 0.05 M hydrochloric acidgenerally followed the order Pb > Cu > Zn > Mn.

Trace elements in Bangladesh paddy soils

A study was carried out to investigate the status of four micronutrients, iron (Fe), copper (Cu), manganese (Mn), and zinc (Zn), and five other trace elements, cobalt (Co), chromium (Cr), nickel (Ni), lead (Pb), and strontium (Sr), in paddy soils of Bangladesh. Soil samples were digested by hydrofluoric acid (HF)‐nitric acid (HNO3)‐perchloric acid (HClO4) for determination of total contents of the nine elements, while DTPA, ASI and 0.1 Mhydrochloric acid (HC1) methods were used for determination of available Fe, Cu, Mn, and Zn. Total trace element contents were found to vary with physiography on which soils are distributed. In general, Ganges Tidal Floodplain soils had the highest content, whereas terrace soils had the lower content. Among the soil properties examined, clay content had a good relation with total trace element contents in the topsoil, except for Sr. Based on the variation with physiography or clay content, the nine trace elements could be grouped into six groups: Cu, Fe and Zn, Pb, Co and Cr and Ni, Mn, Sr. According to the extractable levels of four micronutrients, Bangladesh paddy soils had the medium to optimum amounts of Fe and Cu, but were deficient sporadically in Mn and extensively in Zn. It was indicated that paddy soils of Bangladesh are yet to be polluted with heavy metals.

Dealing with spills of hazardous chemicals: Some nitrosamides

Spills of N-methyl- N-nitrosourea, N-ethyl- N-nitrosourea, N-methyl- N-nitrosourethane and N-ethyl- N-nitrosourethane can be decontaminated using a mixture of ethanol and saturated aqueous sodium bicarbonate solution. Spills of N-methyl- N-nitroso- p-toluenesulphonamide, N-methyl- N′-nitro- N-nitrosoguanidineand N-ethyl- N′-nitro- N-nitrosoguanidine can be decontaminated with a solution of sulphamic acid in 2 m-hydrochloric acid. In all cases the nitrosamides are completely destroyed and only non-mutagenic reaction mixtures are produced.

The metabolism of dopamine in the blood of ruminant animals: Formation of 3,4-dihydroxyphenylacetaldehyde

1. A stable derivative of 3,4-dihydroxyphenylacetaldehyde (DOPAL) has been prepared that yields a solution of the parent aldehyde when dissolved in 1 M-hydrochloric acid. 2. Dopamine, when injected into the bloodstream of a sheep, is metabolized to DOPAL which is then converted to 3,4-dihydroxyphenylethanol by aldehyde reductase activity associated with the cellular components of the blood, most probably the erythrocytes. 3. In vitro, dopamine is metabolized by ruminant blood plasma to DOPAL, not to DOPET as previously reported. 4. Dopamine is as good a substrate for sheep plasma amine oxidase as benzylamine. 5. The plasma amine oxidase of ruminant animals could be a protection against the effects of dopamine released from the mast cells in these species.

Highly sensitive assay for dopamine-beta-hydroxylase activity in human cerebrospinal fluid by high performance liquid chromatography-electrochemical detection: properties of the enzyme.

This paper describes a new, sensitive assay for dopamine-beta-hydroxylase (DBH) activity in human cerebrospinal fluid (CSF), serum and brain tissues by high performance liquid chromatography (HPLC) with electrochemical detection (ED). Dopamine (DA) was used as a substrate and was incubated under optimal conditions. Norepinephrine (NE) formed enzymatically from DA was isolated by a double-column procedure, the first column of Dowex-50-H+ and the second column of aluminum oxide. NE was adsorbed on the second aluminum oxide column and then eluted with 0.5 M-hydrochloric acid and assayed by HPLC-ED. Epinephrine (EN) was added to each incubation mixture as an internal standard, and this assay was therefore highly reproducible. The peak height in HPLC was linear from 500 fmol to 100 pmol of NE and EN. The lower limit of detection for NE formed enzymatically was about 30 pmol, which indicated that the sensitivity of this procedure was comparable to that of radioassay procedures. We applied the method to measurement of the activity of and examination of some of the characteristics of DBH in human CSF. DBH activity in CSF of Parkinsonian patients was lower than that of control patients. The properties of DBH in human CSF were similar to those in serum and adrenal medulla.

A new in vitro method for the estimation of digestibility using the intestinal fluid of the pig

1. A new in vitro method using the intestinal fluid of the pig for predicting the digestibility of diets was proposed.2. A 0.5 g sample of pig diet was placed in a 100 ml Erlenmeyer flask, 20 mg pepsin (EC 3.4.4.1) in 10 ml 0.75 M-hydrochloric acid was added, and the mixture was incubated for 4 h at 37°. Then, after neutralization with 0.2 M-sodium hydroxide, 10 ml of intestinal fluid was added and incubated for an additional 4 h at 37°. This fluid was obtained from a pig fitted with a simple cannula in the upper jejunum. After the two-stage incubations, the contents of the flask was centrifuged for 10 min at 1250 g and the residue transferred to preweighed filter paper for dry matter (DM) and crude protein (nitrogen × 6.25; CP) determinations. The in vitro DM and CP digestibility was calculated on the basis of the original DM and CP content of the diet respectively.3. The intestinal fluid could be stored at ∓ 20° for 60 d without losing its activity on DM and CP digestion.4. A high correlation was found between this in vitro method and the standard in vivo procedures, for seven diets commonly used for growing or adult pigs, when diets were ground to pass through a 1 mm screen for the in vitro experiment, but there was an obvious dissimilarity between the two methods, especially in the case of CP: DM, Y = 1.04X +0.0806 (r 0.98, P < 0.001); CP, Y = 1.70X − 0.6092 (r 0.98, P < 0.001), where Y and X are in vivo and in vitro digestibility respectively.5. This method is rapid and reproducible and particularly suited for the evaluation of a large number of samples. Since this method assesses only stomach and small intestinal digestion, it therefore may require further modification when used for diets which include large amounts of crude fibre. Also, depending on the needs of the investigator, the addition of a correction factor for endogenous faecal nitrogen loss may be required.

An acid-stable analogue of the 3- -D-ribofuranoside of Y-base

A cyclonucleoside analogue of Y(TU) riboside has been prepared and shown to be relatively stable in M-hydrochloric acid solution at room temperature.

ChemInform Abstract: SYNTHETIC STUDIES ON PHOSPHORYLATING REAGENT. V. A CONVENIENT SYNTHESIS OF 2′,3′‐CYCLIC COENZYME A

AbstractZur Darstellung der Titelverbindung (II) wird das mit dem neuen Reagenz 2‐Dimethylamino‐4‐nitro‐phenylphosphat in Gegenwart von Dicyclohexylcarbodiimid phosphorylierte Adenosin (I) als Triäthylammoniumsalz mit D‐Pantethin‐4′,4"‐diphosphat (als Pyridiniumsalz, P‐PaSS) kondensiert (Reaktionsdauer 5 Tage in Pyridin bei 50°C in Gegenwart von Essigsäure oder in DMF‐Bortrifluorid‐ätherat, Ausbeuten bis zu 93%).

Arginine metabolism by spiroplasma citri.

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Synthetic Studies on Phosphorylating Reagent. V. A Convenient Synthesis of 2′,3′-Cyclic Coenzyme A

Abstract A convenient method has been developed for the preparation of 2′,3′-cyclic Coenzyme A (5). It was readily prepared in a good yield from the reaction of adenosine-5′ 2-dimethylamino-4-nitrophenyl phosphate (3) with d-pantethine-4′,4″-diphosphate (4) in the presence of acetic acid in pyridine. Compound 3 and the diphosphate 4 were prepared in a good yield from the condensation of adenosine (1) with 2-dimethylamino-4-nitrophenyl phosphate (2) in the presence of dicyclohexylcarbodiimide (DCC) and the phosphorylation of d-pantethine with 2, respectively. Phosphate 5 was hydrolyzed with 0.1 M-hydrochloric acid and subsequently reduced with 2-mercaptoethanol to confirm its structure of 5. One of the products, Coenzyme A (reduced form) (6) showed 102% activity with phosphotransacetylase.

Determination of lead and cadmium in milk with modern analytical methods.

Methods to determine lead and cadmium at the low mug/kg-level in milk were investigated. Methods tested were differential-pulse anodic-stripping voltammetry (DPASV) and flameless atomic-absorption spectrophotometry (FAAS). Under the circumstances in which these methods were used, the analytical procedure based on DPASV was the most sensitive, with an estimated detection limit of about 0.2 mug/1 for lead and cadmium in liquid milk. The pretreatment of the milk samples before the DPASV-analysis included: freeze-drying, ashing in a muffle furnance at 550 degree C and finally dissolution of the ash in 0.1 M-hydrochloric acid. The recoveries of known amounts of lead and cadmium added to milk were 95 and 59%, respectively. A survey of the contents of lead and cadmium in the Swedish manket milk was performed. This investigation showed that the average lead content in Swedish market milk was 2.0 mug/1, with a standard deviation of 0.5 mug/1. The cadmium content was below 0.2 mug/1 in all samples analyzed.

Intramolecular catalysis. Part III. Hydrolysis of 3′- and 4′-substituted phthalanilic acids [o-(N-phenylcarbamoyl)benzoic acids

Hydrolysis of 3′- and 4′-substituted phthalanilic [o-(N-phenylcarbamoyl)benzoic] acids between pH 0.63 and 5.08 proceeds via undissociated carboxy-group participation at a rate which shows a linear correlation with the pKb of kobs=(k1+k2[H+])/(1 +Ka/[H+])(i) the aniline leaving group. The hydrolysis follows equation (i). In 1.0M-hydrochloric acid phthalanilic acid is hydrolysed nearly 4 × 103 times faster than benzanilide. The rate controlling step is the breakdown of the tetrahedral intermediate, which can be generated independently from N-phenylisophthalimide. N-Phenylisophthalimide has a half-life of ca. 7 s at 24.6° in 0.1 M-hydrochloric acid and is hydrolysed to phthalanilic acid ca. 500 times faster than phthalanilic acid itself and 12–13 times faster than phthalic anhydride. The effect of added dioxan and of increasing acidity on the experimental rate constant for the hydrolysis of phthalanilic acid is reported.

The influence of hydration on base strength. Part V. Hydrazines and oxyamines. Heats of solution and thermodynamics of ionization of the 20 methyl and ethyl substituted hydrazines. Isomerization equilibria for unsymmetrical hydrazinium ions. Substituent constants (σ* values) for amino-groups

Calorimetric heats of solution in water and in 0·1 M-hydrochloric acid are presented for the 20 methyl and ethyl substituted hydrazines. Their difference is given as the heat of neutralization of each hydrazine. The base strengths (pKa) of these hydrazines were determined at five temperatures between 10 and 40° and at several ionic strengths, permitting extrapolation to values at zero ionic strength (pKa0) and calculation of the heats of ionization. An equation is presented by means of which the pKa0 data are correlated with a root mean square deviation ca. 0·15 pK unit in terms of inductive substituent constants (Taft σ*) and hydration parameters dependent on the number of hydrogens on each nitrogen of a hydrazinium ion. It is shown how the equation can be used to calculate heats of ionization, changes in heat capacity on ionization of amines and hydrazines, and equilibrium constants for tautomerization of hydrazinium ions. The changes in heat capacity appear to be only a function of the difference between the σ* constants for hydrogen and the substituents replacing it. Calculated equilibrium constants for the tautomerization: R1R2NHNR3R4⇌ R1R2NNHR3R4 are presented for 26 unsymmetrical hydrazines, including phenylhydrazine. Published pKa0 data for six oxyamines are correlated with a root mean square deviation of 0·08 pK unit.

Effects of acutely induced changes in arterial pH on pulmonary vascular resistance during normoxia and hypoxia in awake dogs.

1. Awake dogs with chronically implanted catheters (pulmonary artery, left atrium, aorta) and electromagnetic flow probe (main pulmonary artery) underwent five types of experiments in succession: (1) slow infusion of 0·4 m-hydrochloric acid; (2) rapid infusion of 1·0 m-sodium bicarbonate; (3) exposure to 30 min of hypoxia (10% O2); (4) exposure to hypoxia after arterial pH had been lowered to 7·30; (5) exposure to hypoxia after pH had been increased to 7·55. Intravascular pressures, pulmonary vascular resistance, cardiac output, arterial gas tension and pH were studied. 2. Acute acidosis (pH 7·21) resulted in a small rise in pulmonary artery pressure, cardiac output and pulmonary vascular resistance, associated with a decrease in Pa,co2. Acute alkalosis (pH 7·61) was accompanied by a small rise in pulmonary artery pressure, marked increase in cardiac output, a fall in pulmonary vascular resistance and mild elevation in Pa,co2. During acidosis hypoxia resulted in a more pronounced rise in pulmonary vascular resistance than during alkalosis (P < 0·01). 3. The study provides evidence that in the intact, awake dog with its compensatory mechanisms acute alkalosis decreases pulmonary vascular resistance by decreasing vascular tone and/or recruitment of pulmonary vascular channels; it diminishes the vasoconstrictive response to hypoxia; conversely, mild acidosis increases the pulmonary vascular resistance slightly and enhances vasoconstriction during hypoxia to a small extent.

Bonding studies of compounds of boron and the group IV elements. Part VIII. Heats of hydrolysis and bond energies for some trimethylmetalyl derivatives Me3M–X(M = Si, Ge, and Sn)

The heats of hydrolysis, in aqueous 1 M-hydrochloric acid, of one silicon, five germanium, and eight tin(IV) compounds of type (Me3M)nX (where M = Si, Ge, or Sn, n= 1–3, and X is a univalent ligand in which the donor atom adjacent to M is N, O, S, Cl, Br, or I) to give (Me3Si)2O, (Me3Ge)2O, and (Me3SnOH)2 have been measured. From these, standard heats of formation have been calculated as follows: ΔHf°(Me3Si·OEt), I =–126·4 ± 0·7; ΔHf°[(Me3Ge)2O], I =–136·0 ± 4·0; ΔHf°(Me3GeCl), I =–71·6 ± 2·1; ΔHf°(Me3GeBr), I =–62·1 ± 2·1; ΔHf°(Me3Ge·OEt), I =–95·8 ± 2·2; ΔHf°(Me3Ge·SBun), I =–64·7 ± 2·1; ΔHf°(Me3Ge·NMe2), I =–37·1 ± 2·2; ΔHf°(Me3SnCl), c =–58·4 ± 1·2; ΔHf°(Me3SnBr), c =–48·8 ± 1·3; ΔHf°(Me3SnI), I =–31·2 ± 1·1; ΔHf°(Me3SnOH), c =–90·8 ± 1·2; ΔHf°(Me3Sn·OEt), I =–73·1 ± 1·5; ΔHf°(Me3Sn·SBun), I =–47·1 ± 1·6; ΔHf°(Me3Sn·NMe2), I =–13·3 ± 1·4; ΔHf°[(Me3Sn)2NMe], I =–31·5 ± 2·5; ΔHf°[(Me3Sn)3N], c =–29·2 ± 3·6 kcal mol–1. Gas-phase enthalpies of formation of these compounds and thermochemical bond energy terms E(M–X) have been calculated. Group trends show that, for constant X, E(C–X) E(Ge–X) > E(Sn–X), whereas E(C–Y) > E(Si–Y)(Y = H or Me). Another conclusion is that the ‘softness’(in terms of ΔH of reactions) of the acid Me3M+ increase in the order C < Si < Ge < Sn; several chemical reaction types are examined in this light.

Neurophysins of the human pituitary gland.

The polypeptide hormones of the posterior pituitary gland, oxytocin and vasopressin, can be precipitated out of solution by the addition of sodium chloride to an extract of the gland. The hormones are salted-out complexed to the soluble proteins known as neurophysins and this protein-hormone complex has been found to possess the pressor and oxytocic activities in ratios similar to those found in the fresh gland (van Dyke, Chow, Greep & Rothen 1942). Neurophysins have been isolated from the pig (Uttenthal & Hope, 1970), ox (Rauch, Hollenberg & Hope, 1969) and cod (Pickering, 1968). In the present paper the proteins precipitated from the posterior lobe of the human pituitary gland were investigated by gel exclusion chromatography and starch gel electrophoresis, and their ability to bind oxytocin and vasopressin was determined. Acetone-dried posterior pituitary lobes (2·4 g) were extracted for 24 h at 4 °C in 0·1 m-hydrochloric acid (100 ml),

Thermodynamics of the actinide elements. Part I. Heats of formation of crystalline neptunium tetrachloride, neptunium oxide dichloride, and neptunium trioxide monohydrate, and a new determination of the heat of formation of the Np III and Np IV ions in M-hydrochloric acid

The following heats of solution have been measured: neptunium metal in oxygen-free 1M-HCl, to yield NpIII, –126·2 ± 0·2 kcal. mole–1; neptunium metal in 1M-HCl–0·005M-Na2SiF6 to yield NpIV, –166·0 ± 0·2 kcal. mole–1; NpCl4(c) in 1M-HCl and 1M-HCl–0·005M-Na2SiF6, –53·87 ± 0·13 and –54·40 ± 0·10 kcal. mole–1, respectively; NpOCl2(c) in 1M-HCl, –33·64 ± 0·12 kcal. mole–1; NpO3,H2O(c) in 1M-HCl and 1M-HClO4, –12·70 ± 0·10 and –12·85 ± 0·10 kcal. mole–1, respectively.