Jolanta Borkowska-Burnecka

Determination of toxic and other trace elements in calcium-rich materials using cloud point extraction and inductively coupled plasma emission spectrometry.

A cloud point extraction (CPE) procedure for the simultaneous separation and preconcentration of Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn from materials rich in calcium prior to trace element analysis by inductively coupled plasma optical emission spectrometry (ICP OES) was developed. The method is based on the formation of hydrophobic complexes of the metal ions with PAN or 5-Br-PADAP, followed by their extraction into a surfactant-rich phase using Triton X-114 as the surfactant. The main variables affecting the extraction process, such as pH, concentration of surfactant and chelating agent were optimised. Under the optimum conditions the obtained limits of detection for Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn were of 4.0, 4.3, 2.1, 1.9, 0.3, 5.6, 40 and 2.0 microg L(-1), respectively. The RSD values for 10 replicates were from 1.5% for Mn to 11% for Pb. The accuracy of the procedure was verified by analysis of certified reference material NIST 1400 (Bone Ash) and by recovery tests. The optimised method was successfully applied for the simultaneous determination of trace elements in dolomites used by different fertiliser factories.

Ultrasound- and microwave-assisted extractions followed by hydride generation inductively coupled plasma optical emission spectrometry for lead determination in geological samples.

Followed the current idea of simplified sample pretratmet before analysis we evaluated the procedure for the determination of Pb in calcium-rich materials such as dolomites after ultrasound- or microwave- assisted extraction with diluted acids using hydride generation inductively coupled plasma optical emission spectrometry (HG-ICP-OES). Corresponding Pb hydride was generated in the reaction of an acidified sample solution with NaBH4 after pre-oxidation of Pb(II) to Pb(IV) by K3[Fe(CN)6]. Several chemical (acidic media: HCl, HNO3 or CH3COOH, concentration of the reductant as well as type and concentration of oxidazing agents) and physical (reagents flow rates, reaction coil length) parameters affecting the efficiency of plumbane formation were optimized in order to improve the detectability of Pb using HG-ICP-OES. Limitation of the method derived from the matrix effects was pointed out. Employing Pb separation by HG technique allows the significant reduction of interferences caused by sample matrix constituents (mainly Ca and Mg), nevertheless they could not be overcame at all, hence calibration based on the standard addition method was recommended for Pb quantification in dolomites. Under the selected conditions, i.e. 0.3 mol L(-1) HCl, HNO3 or CH3COOH, 1.5% NaBH4 and 3.0% K3[Fe(CN)6] the limits of detection (LODs) between 2.3-5.6 μg L(-1) (3.4-6.8 μg L(-1) considering matrix effects) and the precision below 5% were achieved. The accuracy of the procedure was verified by analysis of certified reference materials (NCS DC70308 (Carbonate Rock) and NIST 14000 (Bone Ash)) and recovery test with satisfactory results of Pb recoveries ranging between 94-108% (CRMs analysis) and 92-114% (standard addition method). The applicability of the proposed method was demonstrated by the determination of Pb in dolomites used by different fertiliser factories.

Boron content in daily meals for preschool children and school youth

Boron content in daily me als for preschool children and school youth was studied in this research. The boron content was measured in the meals taken from Wroclaw preschool and boarding school in December, March, June, and September. The whole meal was homogenized. Four grams of sample were mineralized and analyzed by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Statistical assessment of the results was made with the Statistica v.5.1 program. The recovery was determined by the use of the standard additions method to evaluate the accuracy of the procedure. The mean boron content in 1 kg dry weight of a preschool meal was 2.31 mg B/kg dry wt, and in boarding-school meals, it was 2.15 mg B/kg dry wt. Based on these results, the estimated daily boron intake was calculated. The daily boron intake from food by preschool children was found to be 1.01 mg B/d for children and 1.2 mg B/d for youth. The actual intake of boron from food was determined after having related the quantity of the element to 1 kg of body weight. In the case of children, the mean intake of boron was 0.05 mg B/kg body wt/d, whereas in teenagers, it was 0.016 mg B/kg body wt/d. The results of this research show no significant differences between daily boron intake for preschool children and boarding-school youth.

Vibrational analysis of the A3Π0-X1Σ+ and B3Π1-X1Σ+ subsystems of the GaBr molecule

Abstract The emission band spectrum of gallium monobromide has been excited in a dc hollow cathode discharge. bands of the 3Π0,1−X1Σ+ system, lying in the range from 340 to 370 nm have been recorded at high resolution and measured. The previous vibrational analysis has been revised and corrected. New vibrational assignment has been proposed and improved vibrational constants of the upper and lower electronic states have been determined.

Comparison of Spectra Excited in HF and DC Hollow Cathode Discharges

Abstract Spectra excited in hollow cathode discharges operating at high frequency (27.2 MHz) and direct currents have been compared. The cathodes made of copper, brass and steel and argon as a carrier gas were used. Line intensity ratios (Ihf/Idc) for species excited at different pressures have been investigated and discussed.

Emission Characteristics of the D.C., 100 kHz and 13.5 MHz Hollow Cathode Discharges

Abstract Hollow cathode discharges in argon at various pressures and currents have been studied by optical emission spectroscopy. The cathodes were made of copper, bronze and brass. The discharges were supplied by direct, 100 kHz and 13.5 MHz currents. Atomic and ionic spectra of plasma gas and elements of cathode materials and molecular bands of ZnH and PN formed due chemical reactions between plasma components have been excited and measured. Relations between emission intensities, excitation temperatures and discharge conditions have been analysed and discussed.

Study of Vaporization and Excitation Processes in a Hollow Cathode Discharge

Abstract Vaporization and excitation processes in a hollow cathode discharge have been studied here. Samples containing various lead compounds mixed with copper powder, without and with an addition of potassium halides, were analyzed. Influence of operating conditions (such as gas pressure, kind of analyzed Pb-compound and the addition of the easily ionizable element) upon the lead, copper, argon and potassium line intensities and the intensity ratio of Ar II/Ar I have been investigated. Excitation mechanisms and an importance of chemical processes have been discussed.

Rotational analysis of the a4Σ - X2Π 0-0 band of germanium monobromide

Abstract The emission spectrum of germanium monobromide in the 360–420 nm region has been examined at high resolution. Three 0-0 bands at 368.8, 383.8, and 385.1 nm have been rotationally analyzed. It was concluded that the observed band system had arisen from a 4 Σ − - X 2 Π transition. The GeBr molecular constants for the upper and lower states have been determined for the first time using 4 Σ − and 2 Π state Hamiltonians with higher order interaction constants and a nonlinear least-squares procedure. The isotopic effects have been studied.

Fluorine Determination and Matrix Effects in DC and HF Hollow Cathode Discharges

Abstract The InF bands excited in a hollow cathode discharge have been used for fluorine determination in solid samples (containing from 10−6 to 10−1% F) and solutions (at the F− concentrations from 1 μg/ml to 1 mg/ml). The discharge operated at direct current (dc) or high frequency current (hf). A dependence of the InF band intensities on the fluorine concentration has been investigated. Matrix effects caused by some metals and halides have been studied and discussed.

Rotational analysis of the 383.8 nm band of the GeBr molecule

Abstract The 383.8 nm band of the GeBr molecule, recorded at high resolution, has been rotationally analyzed. Rotational constants of the upper and lower states have been determined from lines of six, main isotopic molecules of GeBr. The band has been proposed to be assigned as the 4σ−−X2π3/2 0–0 transition.