A simple, accurate and reliable method for direct electrothermal atomic absorption spectrometric (ETAAS) determination of chromium in serum and urine samples without any preliminary sample pretreatment is described. Instrumental parameters are optimized in order to define: the most suitable atomizer, optimal temperature program and efficient modifier. An appropriate quantification method is proposed taking into account a matrix interference study. Pyrocoated graphite tubes and wall atomization, pretreatment temperature of 700• C, atomization temperature of 2600 • C, hydrogen peroxide as modifier and standard addition calibration are recommended. The accuracy of the method proposed for Cr determination in serum and urine was confirmed by comparative analysis of parallel samples after wet or dry ashing as well as by the analysis of two certified reference materials: Serum, Clin Rep 1 and Lypochek Urine, level 1. The detection and determination limits achieved for both matrices are 0.08 µg/L and 0.15 µg/ L respectively. The relative standard deviation varied between 15 and 18 % for the chromium content in the samples in the range 0.08-0.2 µg/L and between 4 and 7 % for the chromium content in the range 0.2-2.0 µg /L for both matrices.
Methods for the direct determination of Ni in human blood serum and urine by electrothermal atomic absorption spectrometry (ETAAS) are described. Hydrogen peroxide was proposed as matrix modifier, assisting thermal decomposition of proteins during the ashing step. A pyrolysis temperature of 1,200 degrees C was found to be optimal while 2,100 degrees C and 2,200 degrees C were found to be optimal atomizing temperatures for Ni in serum and urine respectively. Calibration was performed by using a calibration curve prepared with aqueous standard solutions of Ni (glycine must be used as modifier for Ni in aqueous solutions). The limits of detection, defined as the blank values plus 3 times the standard deviation of the blank values, were 0.2 microg/L for both serum and urine samples. Relative standard deviations for serum samples with concentrations of Ni in the range 0.5-2 microg/L were 10-15% and for urine samples with Ni concentrations in the range 0.5-2.5 microg/L were 8-10%.
The presence of some chemical compounds at higher levels than maximum permissible concentrations (MPC) in the drinking water, suggests of water resources pollution. In this paper the following elements were analyzed: total arsenic, cadmium, lead, cooper and zinc. Twelve samples of water from the water supply system from the city of Skopje were examined during one year from three different springs. Also, ten samples of bottled water from three producers from the Macedonian market were tested.The determined average mass concentrations of total As, Cd(II), Pb(II), Cu(II) and Zn(II) in the analyzed water samples from the water supply system are 1.35 μg/l, 0.06 μg/l, 0.6 μg/l, 0.9 μg/l and 1,12 μg/l, respectively, and for the tested bottled water, the mean values ranges from 0.56 - 0.83 μg total As / l, 0.053 - 0.056 μg Cd(II)/l, 0.51 - 0.54 μg Pb(II)/l , 0.6 - 0.87 μg Cu(II)/l and 0.68 - 0.8 μg Zn(II)/l water.The following instrumental analytical methods and techniques were used for the analysis of the tested samples of drinking water: flame atomic absorption spectroscopy (AAS), atomic absorption spectroscopy with hydride cеll, electrothermal atomic absorption spectroscopy.The obtained results are shown in tables and graphic form. According to the obtained results a comparative analysis was carried out indicate that it is a water of good quality that can be used in different branches of the process industry.The obtained results in this paper do not exceed the values of the MPC of the Republic of Macedonia prescribed by the legal regulations for the drinking water, which confirm the health safety of the drinking water from the water supply system in the city of Skopje and the packed waters from the Macedonian market in relation to the tested elements.
The availability of clean water is a challenge around the world. In recent decades, environmental pollution through the excessive discharge of organic and inorganic water in water contributes to large quantities of wastewater. These halts are a major threat to the surrounding ecosystem and human health if they are not treated before being discharged into the environment. Therefore, there is an increasing attraction for the development and improvement of more accessible methods for wastewater treatment. Today, the adsorption, as a method for purifying the waters from pollutants, is paid great attention because it represents a simple, efficient and economical method, which gives the opportunity to apply a large number of natural and synthetic adsorbents. In the group of natural adsorbents that are used to remove water from the water systems, there are more materials, such as: inorganic materials, activated carbon based on biomass, agricultural solid waste, biosorbents and microbial biomass.
Безбедноста на житата и житните производи е од големо нутритивно и токсиколошко значење, бидејќи житната индустрија и нејзините производи имаат голема економска и социјална важност на светско ниво. Во ова пилот истражување е испитана концентрацијата на токсичните елементи во траги арсен, кадмиум и олово, во три мостри од различни производители на ориз: 11,67+5,69mg/kg, 25,67+6,43mg/kg, 47,67+18,01mg/kg, пченично брашно: 7+5mg/kg, 9+1,73mg/kg, 69,92+16,92mg/kg за As, Cd и Pb, соодветно, и производи од брашно (леб: 9,33+2,08mg/kg, 6,67+0,58mg/kg, 36+3,6mg/kg, тестенини: 1,61+1,15mg/kg, 2,67+2,08mg/kg, 30+7mg/kg и чајни колачи: 4,67+4,04mg/kg, 1,33+0,58mg/kg, 53+9,64mg/kg за As, Cd и Pb, соодветно) од македонскиот пазар, со употреба на хидридно генерирачка и електротермичка атомска апсорпциона спектрометрија со мокра дигестија. Извршена е пресметка на учеството во просечниот дневен внес за токсични елементи внесени преку дневна консумација на жито и производи од жито (20% од целодневниот оброк). Придонесот на As (9,86%), Cd (10,02%) и Pb (11,39 %) спореден со просечниот дневен внес и прифатливиот толериран дневен внес, PTDI, беше низок, што покажува дека овие производи се безбедни за употреба во однос на испитаните токсични елементи. Нивоата на токсичните елементи во мострите на македонскиот ориз, пченично брашно и производи од брашно се споредливи со резултатите добиени од различни делови од светот и нивниот внес не претставува здравствен ризик за потрошувачите.
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