The polarographic determination of zinc and manganese in plant and animal tissues and soils

A method is proposed whereby microgram quantities of zinc and manganese may be simultaneouly extracted with excess sodium diethyldithiocarbamate in the presence of tartrate at pH 5.5, the extracts decomposed and the metals polarographed in a lithium chloride supporting electrolyte. Iron must first be removed with cupferron, and the interference by cobalt and nickel is overcome by the use of dimethylglyoxime prior to the extraction. The method may be applied to the digests of animal tissues, plant materials or soils.     

Square-wave polarographic determination of traces of copper in water

Summary A square-wave polarograph [3] has been used to determine trace amounts of copper in potable water and in Iowa River water. By using a combination of sodium chloride (1.0 M) and perchloric acid (0.07 M) as a supporting electrolyte under acidic conditions (pH<1), 2 ppb copper could be determined in the samples without and with preconcentration. Copper in the samples was determined with reproducibility of ± 0.13 ppb and so this technique is more reliable than a more used determination of complex salts by atomic absorptionspectrophotometry.

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Bestimmung von Spuren Kupfer in Wasser durch Square-Wave-Polarographie

Zusammenfassung Ein früher [3] beschriebener Square-Wave-Polarograph wurde zur Spurenbestimmung von Kupfer in Trink- und Flußwasser (Iowa River) benutzt. Der verwendete Grundelektrolyt war 1,0 M an NaCl und 0,07 M an HClO₄ (pH<1). Noch 2 ppb Cu konnten mit und ohne Vorkonzentrierung bestimmt werden. Die Reproduzierbarkeit war ± 0,13 ppb. Das Verfahren ist zuverlässiger als die Bestimmung über Komplexsalze durch Atomabsorptionsspektrophotometrie.

One of the authors wishes to thank Prof. Dr. F. Duke for the acception at the University of Iowa and Prof. Dr. B. Teak for the discussion.     

Changes in copper, lead and zinc concentrations in plants from paper mill sludge-treated soils

Effects of paper mill sludge addition on the availability of metals were studied on different soils both laboratory and naturally polluted; copper, lead and zinc concentrations were determined in Hordeum Distichum plants grown on the untreated and on sludge-treated soils. In some case a decrease of metal concentration is observed on sludge-treated soils; these results are consistent with the reduction of metal mobile forms in the soil, before plant growth. The decrease of metal availability in sludge-treated soils may be related with the pH value of the soil after sludge addition.     

The polarographic determination of indium in zinc-base alloys : The determination of indium in zinc and in zinc alloys of low aluminium content

Studies of the application of an 8-hydroxyquinoline extraction and of a zinc oxide “collection” procedure for the separation of trace amounts of indium from zinc alloys are described and discussed. A combination of radio-chemical and polarographic determination were employed for this work. A polarographic method for the determination of indium in zinc and in zinc alloys of low aluminium content is presented     

The polarographic determination of thallium

A polarographic method is described for the determination of thallium in sodium triphosphate supporting electrolyte. The incorporation of 0.1% camphor in the electrolyte displaces the cathodic steps of many interfering ions, e.g., lead(II), copper(II), iron(III) and bismuth(III) to a more negative potential (1?.0 V), well away from the thallium step which remains unaffected.     

Separation of zinc and copper with cyanoacetamide in the determination of zinc

The new use of cyanoacetamide as a selective masking agent for copper in the determination of microgram amounts of zinc with zincon is described. It is very possible that the unique masking action of this compound may have importance in eliminating the interference of copper in other spectrophotometric and titrimetric procedures for zinc thereby reducing the time required to complete the analysis by decreasing or eliminating laborious separation or extraction techniques. The possibility of using cyanoacetamide as a masking agent for other ions should not be overlooked.     

Differential pulse polarographic determination of dicrotophos, crotoxyphos and chlorfenvinphos in grains and soils

A simple, sensitive and rapid differential pulse polarographic method has been developed for the quantitative determination of organophosphorus pesticides such as dicrotophos, crotoxyphos and chlorfenvinphos in agricultural formulations in universal buffers of a pH range 2.0-12.0. The sample is treated with ethanol to facilitate the dissolution of these pesticides. Both standard addition and calibration methods can be used for the analyses. The lower detection limits are 1.25x10(-9), 1.05x10(-9) and 1.0x10(-9) M, respectively. The method can be applied successfully to determination of these pesticides in grains and soil.     

The polarographic behavior and determination of glafenine

Glafenine was found to be reducible at the dropping-mercury electrode (DME) in Britton-Robinson buffer (BRB) over the whole pH range. In the alkaline range, a well-defined cathodic wave was produced. The wave was characterized as being diffusion-controlled and partially affected by adsorption phenomena. A method was proposed for the determination of glafenine in tablets and the results obtained were satisfactorily accurate and reproducible.     

The effect of zeolites on copper uptake by plants growing in contaminated soils

Three-year pot experiments were carried out in a greenhouse with the aim of reducing the copper content in the 2nd link of the soil-plant-animal (man) trophic chain. For this purpose, synthetic zeolites of the 3A, 4A, 5A and 13X type were introduced into copper contaminated soils at levels of 1, 2 and 3% by weight in relation to the soil mass. Mono- and dicotyledonous plants were cultivated in mixtures of soils with the zeolites. The copper content in lettuce grown in the contaminated soil decreased in the presence of zeolites by 29–77%, in grass by 41–78%, in oats by 45–64% and in beets by 21–41%, as compared to the control.     

The polarographic determination of lead in tin-base alloys

A polarographic method for the determination of lead in tin-base alloys is described For alloys containing more than 2% lead no separations are necessary; in those with a lower lead content, most of the copper present must be removed as cupric oxide Results are exact: ±4% of the amount of lead present.     

Simultaneous spectrophotometric determination of cadmium, copper and zinc

A method for the simultaneous spectrophotometric determination of cadmium, copper and zinc based on the formation of their complexes with 1,5-bis(di-2-pyridylmethylene)thiocarbonohydrazide is proposed. The absorption curves of these complexes overlap severely in the scanning range 380–480 nm. The analyte concentrations are calculated by a least squares fit of the pure spectra to the mixture spectra. A linear determination range of 0.1–1.7 μg/ml for cadmium, 0.1–1.3 μg/ml for copper and 0.2–1.2 μg/ml for zinc were obtained. The effect of interference was studied. The method has been applied to the determination of these metal ions in various type of materials.     

The polarographic determination of chromium in aluminum alloys

A convenient polarographic method for the determination of 0.1–0.5% of chromium in aluminum alloys is described. The alloy is dissolved in a bromine water-sodium hydroxide mixture; after suitable treatment, chromate is determined polarographically. Specific directions for the simultaneous running of a blank experiment are given ; this provision greatly improves the accuracy of the results obtained.     

Determination of copper(II) and zinc(II) in blood by spectrophotometry and polarographic methods

Summary Determination of copper with picramine R and of copper and zinc by amalgam polarographic technique with accumulation, have been developed for samples of 0.2–1 ml of blood.

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Zusammenfassung Die Bestimmung von Kupfer mit Pikramin R und von Kupfer und Zink durch Polarographie nach elektrolytischer Anreicherung als Amalgam aus 0,2 bis 1 ml Blut wurde ausgearbeitet.

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Reference solution 1 contains (g/ml): 900 NaCl, 400 NaHPO₄, 200 KC1, 100 CaCl₂, 10 NaHCO₃, 6 Zn²⁺, 1.5 Cu²⁺, 1 AI³⁺+, 0.5 Ti⁴⁺, 0.2 Mn²⁺, 0.1 Pb²⁺, 0.06 Co²⁺, 0.05 Ni²⁺.Reference solution 2 is the same plus Fe³⁺, 500 g/ml.     

Ultraviolet irradiation and polarographic adsorptive complex wave techniques for the simple and rapid simultaneous determination of trace amounts of zinc,lead and copper in human hair

Polarographic adsorptive complex waves in the presence of catechol violet were studied for the simple and rapid simultaneous determination of traces of zinc, lead and copper in human hair and UV irradiation techniques were compared with conventional acid digestion procedures. UV irradiation of acidified hair with a 500-W mercury are lamp releases bound zinc, lead and copper after 3 h. Compared with the acid digestion procedure, the blank of the UV irradiation method is lower, the amounts of reagents used are smaller and the sample manipulations are simpler. The mechanisms of the polarographic adsorptive complex waves of Zn-, Pb-Cu- catechol violet are discussed.     

Adsorption and desorption of copper and zinc in the surface layer of acid soils

The environmental and health effects of the contamination of soils by heavy metals depend on the ability of the soils to immobilize these contaminants. In this work, the adsorption and desorption of Cu and Zn in the surface layers of 27 acid soils were studied. Adsorption of Cu(II) from 157-3148 mumol L(-1) solutions was much greater than adsorption of Zn(II) from solutions at the same concentration. For both Cu and Zn, the adsorption data were fitted better by the Freundlich equation than by the Langmuir equation. Multiple regression analyses suggest that Cu and Zn adsorption depends to a significant extent on pH and CEC: for both metals these variables accounted for more than 80% of the variance in the Freundlich pre-exponential parameter K(F), and pH also accounted for 57% of the variance in 1/n for Zn and, together with carbon content, for 41% of the variance in 1/n for Cu. The percentage of adsorbed metal susceptible to desorption into 0.01 M NaNO3 was greater for Zn than for Cu, but in both cases depended significantly on pH, decreasing as pH increased. In turn, both pH(H2O) and pH(KCl) are significantly correlated with cation exchange capacity. Desorption of metal adsorbed from solutions at relatively low concentration (787 mumol L(-1)) exhibited power-law dependence on Kd, the quotient expressing distribution between soil and soil solution in the corresponding adsorption experiment, decreasing as increasing Kd reflected increasing affinity of the soil for the metal. The absence of a similarly clear relationship when metal had been adsorbed from solutions at relatively high concentration (2361 mumol L(-1)) is attributed to the scant between-soil variability of Kd at these higher concentrations. In general, adsorption was greater and subsequent desorption less in cultivated soils than in woodland soils.     

Rapid spectrophotonietric determination of copper in steel with zinc dibenzyldithiocarbamate

A rapid spectrophotometric method employing zinc dibenzyldithiocarbamate is described for determining copper in a wide variety of steels. The acidity is not critical (0.5-2N) and the colour of the complex is stable for > 1 hr. The range of the method is 0.005-5% copper and 6 samples can be analysed in about an hour.