Multi-element analysis of milk by ICP-oa-TOF-MS after precipitation of calcium and proteins by oxalic and nitric acid.

In this work a simple technique employing oxalic and nitric acid to cow's milk samples prior to analysis by inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry (ICP-oa-TOF-MS) was introduced. After the precipitation of calcium and proteins via oxalic and nitric acid, respectively, the resulting liquid phase was aspirated with a concentric glass nebulizer for ICP-TOF-MS determination of trace elements. Precipitation of proteins is essential for better separation of solid and liquid phase of modified samples.

Direct electrothermal atomic spectrometric determination of Ag in aqua regia extracts of soils, sediments, and sewage sludge with matrix modification.

Silver is subject to significant interferences caused by high chloride concentrations in electrothermal atomic absorption spectrometry, thus its direct determination in aqua regia leaches from soils, sediments, and sludges is very difficult, especially when using instrumentation equipped with deuterium-lamp background correction (D2). In this study, the interference of the aqua regia medium was successfully eliminated using Pd-citric acid chemical modifier. This chemical modifier was found to be the most advantageous in comparison with Pd mixture with ascorbic acid, tartaric acid, or citric acid-Li based on its ability to suppress the interference originating from different chloride matrix.

Analytical capabilities of inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry (ICP-oa-TOF-MS) for multi-element analysis of food and beverages.

Analytical capabilities of ICP-oa-TOF-MS for rapid, simultaneous and reliable determination of more than 50 major, trace and ultra-trace elements in different food and beverages samples (milk and dairy based products, cereals, meat, offal, sugar and sugar products, potatoes, fats, baby food samples, fruit juices, alcoholic beverages), following microwave closed vessel digestion of samples, were described. Under optimum instrumental conditions, and by using Rh as an internal standard and an external calibration method, ICP-oa-TOF-MS enables an accurate analysis, taking about one minute per a sample for all elements and isotopes of interest even for some elements such Zn, Ni, Cu, As or Co whose assay is more difficult when using conventional quadrupole instruments. In order to verify the accuracy and precision of the proposed method, 8 commercially available reference materials representing 3 major groups of food (milk and dairy based products, meat, cereals) were analysed, yielding results in agreement with certified values and the precision bellow 15%.

Overcoming interference from the alumina matrix on the determination of arsenic at 189 nanometers using electrothermal atomic absorption spectrometry.

A method is described enabling to eliminate the spectral interference from alumina matrix onto As determination at the wavelength 189 nm by electrothermal atomic absorption spectrometry with deuterium background correction. Matrix modification was performed by the addition of ammonium fluoride to protect the formation of aluminium oxide implicated in causing spectral interference and to increase volatility of alumina matrix via the formation of AlF(3). Pre-treating of the pyrolytic graphite platform with a solution of rhodium and citric acid has enabled to stabilize the analyte up to temperature of 1300 degrees C at which most of AlF(3) could be removed from the graphite furnace.

Palladium-citric acid-ammonium fluoride as a matrix modifier for overcoming of interferences occurring during the direct determination of Sn in aqua regia extracts from environmental samples by D2-ETAAS.

When tin is to be determined in such a complex matrix like aqua regia extracts of environmental samples by electrothermal atomic absorption spectrometry (ETAAS), spectral interferences occur when deuterium-lamp (D(2)) background correction is used, even using high pyrolysis temperature of 1400 degrees C achieved with palladium with citric acid chemical modifier. We have found that the further addition of NH(4)F to palladium with citric acid chemical modifier is essential for overcoming the above-mentioned problems for which aluminium oxide is most probably responsible. It is supposed, that NH(4)F enables volatilization of the alumina matrix formed by hydrolysis from the chloride salt and interfering in a gas phase via the formation of AlF(3) which could be, in contrast to aluminium oxide, removed from the graphite furnace during the pyrolysis stage.

Catalytic adsorptive stripping voltammetry versus electrothermal atomic absorption spectrometry in the determination of trace cobalt and chromium in human urine.

Two methods of the determination of cobalt and chromium in human urine of non-occupationally exposed populations-highly sensitive catalytic adsorptive stripping voltammetry (CAdSV) and electrothermal atomic absorption spectrometry (ET-AAS)-are evaluated and compared. The CAdSV methods are based on adsorptive accumulation of a cobalt-nioxime (1,2-cyclohexanedione dioxime) or a chromium-DTPA (diethylenetriammine-N,N,N',N'',N''-pentaacetic acid) complexes on a hanging mercury drop electrode, followed by a stripping voltammetric measurement of the catalytic reduction current of the adsorbed complex in the presence of sodium nitrite in case of cobalt or in the presence of sodium nitrate in case of chromium determination. In the CAdSV procedure UV-photolysis was used for the sample pre-treatment; the ET-AAS determination did not require any separate preliminary decomposition of the analyte urine samples.

Characterization of industrial explosives based on the determination of metal oxides in the identification particles by microwave digestion and atomic absorption spectrometry method.

Identification particles used for the purpose of the post-blast identification of explosives have a coding system based on the combination of metal oxides and their various concentrations. These materials are composed of the polymeric matrix, iron powder (ferromagnetic properties), UV light active dyestuff and various metal oxides in a various ratios. A suitable analytical method has to be used for an accurate characterization of these metal components in the particles in order to find the required information, i.

Interference-free determination of thallium in aqua regia leaches from rocks, soils and sediments by D(2)-ETAAS method using mixed palladium-citric acid-lithium chemical modifier.

The mixture of palladium (chloride) with citric acid and lithium is proposed as a new chemical modifier for the elimination of interference occurred during the determination of Tl in aqua regia extracts from rocks, soils and sediments by electrothermal atomic absorption spectrometry using instrumentation with deuterium-lamp background correction (D(2)-ETAAS). Palladium was preferred to rhodium and platinum as to analyte stabilization, citric acid served as an effective reducing agent facilitating formation of Pd-Tl stable covalent bonds playing an important role in the analyte stabilization. Citric acid in addition helps to remove most of interfering chloride at low temperature.

Ammonium fluoride as a novel chemical modifier for the elimination of magnesium chloride interference on the determination of lead by graphite furnace atomic absorption spectrometry.

Ammonium fluoride was found to be very efficient modifier for the elimination of MgCl(2) interference on Pb determination. Ammonium fluoride probably converts strongly interfering volatile MgCl(2) to less volatile MgF(2) matrix that makes possible the release of Pb analyte at lower temperature, before the matrix starts to vaporize. It was observed likewise that NH(4)F removes the interferences mentioned, i.

N-acetyl-beta-glucosaminidase and albuminuria in acromegaly.

Significantly increased albuminuria and N-acetyl-beta-glucosaminidase activity in serum and urine have been observed in acromegalic patients in comparison with healthy persons (P less than 0.001). No relationship between these biochemical variables and serum growth hormone or insulin concentration was found in our group of patients.

Humoral and renal response to acute volume loading in patients with essential hypertension.

The effect of acute volume expansion (2 liters of saline solution in 2 h) on plasma concentrations of atrial natriuretic factor (ANF), plasma aldosterone concentration (PAC), plasma renin activity (PRA) and their relationship to the renal excretion of urine, sodium and potassium were studied in 6 control subjects and 7 patients with essential hypertension (EH) WHO stage I. Saline infusion provoked comparable rise in plasma ANF in both groups (from 2.98 +/- 0.

[Mutual interaction of the renin-angiotensin system and the atrial natriuretic factor in the renal response to acute volume loading].

The authors investigated dynamic changes and the interaction of the plasma renin activity (PRA), plasma aldosterone (PAC), i.e. the main representatives of sodium retaining systems, and of the atrial natriuretic factor (ANF) the decisive natriuretic substance in acute expansion of the extracellular volume (ECV) by infusion of two litres of saline in six controls, seven patients with essential hypertension and liver cirrhosis without ascites (6 patients) and with ascites (6 patients).

[Compensation in diabetes and serum insulin levels in type I diabetics during insulin pump therapy and after changing to treatment with a combination of short- and long-acting insulin].

Twenty-one type diabetics previously treated in the conventional way with insulin with unsatisfactory results were admitted to hospital. The blood sugar level, serum insulin and non-esterified fatty acids in serum (NEFA) were assessed from 6 a.m.

Glucose metabolism in a patient with insulinoma complicated by hyperosmolar non-ketotic state.

A case of a patient with organic hyperinsulinism complicated by the development of hyperosmolar state is described. The hyperosmolar state was induced by vomiting and dehydration during an acute urinary tract infection. Impairment of glucose metabolism was confirmed by the finding of reduced tissue sensitivity to insulin during a euglycaemic clamp.

Preferential accumulation of radioactivity in rat kidneys after the administration of 125I-labelled Fab antidigitalis antibodies.

125I-labelled Fab antidigitalis antibodies were administered i.p. to rats, whose organs were removed 20 h later and examined for radioactivity.

[The Biostator in the diagnosis and therapy of organic hyperinsulinism].

In 12 patients with the diagnosis of organic hyperinsulinism the authors examined the carbohydrate metabolism on a Biostator, using the method of stabilized glycaemia. They found a highly significantly reduced tissue sensitivity to insulin at the same time a reduced metabolic insulin turnover as compared with healthy subjects (p less than 0.001).

[Relation between atrial natriuretic factor and the renin-angiotensin-aldosterone system in the renal reaction to acute volume loading in patients with essential hypertension].

Investigation of changes of the atrial natriuretic factor plasma concentration (ANF), plasma renin activity (PRA) and the plasma aldosterone concentration (PAC) and their correlation with the renal excretion of urine, sodium and potassium before and after infusion of 2 1 saline in the course of 2 hours in 6 controls and 7 patients with essential hypertension (EH) revealed the same rise of ANF in plasma of both groups (from 2.98 +/- 0.45 to 12.

Use of euglycaemic clamping in evaluation of diazoxide treatment of insulinoma.

The use of diazoxide in patients with insulinoma has been evaluated using the euglycaemic clamp technique. There was significantly reduced mean tissue sensitivity to insulin, expressed as the ratio of glucose disposal rate to serum insulin concentration (M/I), in untreated patients compared to the control group. The metabolic clearance rate of insulin (MCRI) was reduced in the patients before treatment in comparison with the controls.

Extractive photometric determination of gallium with 8-quinolinol in layered crystals of bismuth telluride-estimation of the determination limit.

A method for determining microgram amounts of gallium in milligram samples of layered monocrystals of the type A(V)(2)B(VI)(3) is described. For the separation of 1-5 mug of gallium(III) from a large excess of bismuth in a single extraction the recommended conditions are pH 3.6-4.

Atrial natriuretic peptide concentration and natriuretic hormone activity in plasma of patients with chronic renal failure.

To elucidate further the possible role of atrial natriuretic peptide (ANP) and hypothetical natriuretic hormone (NH) in volume and BP regulation in chronic renal failure (CRF) we measured plasma ANP, digitalis-like substances (DLS) and Na+-K+-ATPase activity (using 86Rb influx into RBC) in 9 patients with CRF before and after hemodialysis. Volume expansion between consecutive dialyses led in all patients to the elevation of plasma ANP (83.4 +/- 14.

Insulin receptors and glucose homeostasis in type 2 diabetics influenced by acetyl-salicylic acid treatment.

The effect of acetyl-salicylic acid administration on insulin receptors on the erythrocytes and the changes of glucose homeostasis examined by hyperglycaemic clamps were evaluated in 8 Type 2 diabetics. Significantly increased number of insulin receptors and decreased insulin affinity constants were found in diabetics after the acetyl-salicylic acid treatment (p less than 0.02).

Radioimmunoassay of atrial natriuretic peptide in human plasma: application to studies of volume and blood pressure homeostasis.

Sensitive radioimmunoassay for determination of immunoreactive atrial natriuretic peptide (ANP) in human plasma was developed and employed for the study of plasma ANP concentrations in healthy controls under basal conditions (2.4 +/- 0.1 pmol/l) and during volume expansion by saline infusion (9.