Electrothermal Atomization Research Articles

Biomonitoring of Aluminum in Urine of Young Lebanese Children Living in Beirut.

BackgroundAluminum (Al) is a ubiquitous, toxic metal to which infants and young toddlers are highly vulnerable. High Al exposure has been associated with various human pathologies. The aim of the present biomonitoring (BM) study was to provide a background for the levels of urinary aluminum (Al) in children ages 7 months to 4 years living in Beirut.Material/MethodsWe collected and analyzed 120 urine specimens using the Shimadzu Atomic Absorption Spectrophotometer-6300 system equipped with an electrothermal atomization, and using a GFA-EX7i graphite furnace.ResultsThe mean and standard deviation of Al level in urine revealed 8.978±12.275 μg/L, which is within the lower range of each of populations in Germany, Taiwan, and Poland. Vitamin intake, powder rice, and the use of Al utensils proved to be major determinants for Al level in urine (significant at 95%).ConclusionsThe Shimadzu Atomic Absorption Spectrophotometer-6300 system proved again to be an optimal and reliable instrument that can be used for the determination of Al level in urine, especially if using a GFA-EX7i pyrolytic graphite furnace. High levels of Al were found in the urine of Lebanese children. However, the frequent consumption of canned food did not prove to be a significant factor in determining the Al level in urine.

Effects of Dihydroquercetin on Behavior of Albino Rat Offspring with Transgenerational Chemical Body Burden

Introduction. Lead pollution is a common environmental problem. Having no physiological functions, this toxicant has a negative polytropic impact on a body, including neurotoxic, reproductive, and transgenerational effects. The mechanism of lead toxicity is oxidative stress. Flavonoids have active antioxidant properties. They are widely represented in plant foods, are able to restore protective capabilities of cells and have chelating properties with respect to lead. One of the representatives of this group of substances is dihydroquercetin. The objective was to study the effect of dihydroquercetin on behavior of rats with hereditary chemical body burden exposed to lead at 60 mg/kg during 25 days. Materials and methods. We studied the behavior of rat offspring in an open field and established their blood lead levels by electrothermal atomization atomic absorption spectrometry. For statistical processing the U-Mann – Whitney test was used. Results. In the present experiment, the effect of lead on the offspring of male albino rats exposed to 60 mg/kg of lead for 25 days caused changes in the activity of animals in the open field. The severity of changes was more pronounced in animals with a hereditary chemical body burden. These animals showed a decrease in orientation and physical activity and increased anxiety. In rats with a hereditary burden, changes in behavior were detected when administering dihydroquercetin. The activity of animals demonstrated a positive dynamics: we observed a statistically significant increase in physical activity and orientation. The number and duration of behavioral acts approached control values. Conclusions. The revealed effects of lead on the offspring of albino rats with a transgenerational chemical body burden require further study to understand the mechanism of the phenomenon.

СОДЕРЖАНИЕ ХИМИЧЕСКИХ ЭЛЕМЕНТОВ В ПОЧВАХ И ПОВЕРХНОСТНЫХ ВОДАХ ПЛОСКОГОРЬЯ УКОК (ЮГО-ВОСТОЧНЫЙ АЛТАЙ)

Актуальность исследования обусловлена слабой изученностью химического состава почв и поверхностных вод плоскогорья Укок, являющегося объектом всемирного наследия ЮНЕСКО. Цель: изучить уровни содержания химических элементов в почвах и поверхностных водах центральной, южной и юго-восточной части плоскогорья Укок и дать эколого-биогеохимическую оценку этой малоизученной территории. Объекты: основные типы почв (криоаридные и горные лугово-степные, горные луговые, горные тундровые) и поверхностные воды (реки Жумалы, Калгуты, Аргамжи, Ак-Алаха, Тархата и озеро Укок) плоскогорья Укок (Республика Алтай, Российская Федерация). Методы. Содержание металлов в почвах определено методом эмиссионного спектрального анализа в Институте геологии и минералогии СО РАН, общее содержание микроэлементов в природных водах – в химико-аналитическом центре ИВЭП СО РАН спектрометрическим методом с использованием электротермической атомизации. Результаты. Представлен химический состав различных типов почв и поверхностных вод высокогорного плоскогорья Укок. Уровни содержания химических элементов в почвах плоскогорья не превышают их кларков в почвенном покрове и соответствуют их концентрациям в горно-тундровых почвах Алтая. Исключением являются почвы и почвообразующие породы над Калгутинским W-Mo-V-Cu месторождением, где отмечается аномально высокое содержание вольфрама – до 30–60 мг/кг. С ореолами рассеяния и воздействием отвалов штольни и хвостохранилища обогатительной фабрики этого месторождения мы связываем повышенное содержание Cu в водах реки Калгуты – 16 мкг/дм3 и в почвах бассейна. Почвы плоскогорья отличаются невысоким валовым содержанием P и Са, но обогащены калием – его содержание превышает 2 % в большинстве образцов. Концентрация фосфора в почвах плоскогорья Укок возрастает с запада на восток, от выровненной (центральной) части к горным окаймлениям, что обусловлено фосфоритоносностью коренных пород Алтае-Саянской горной страны. Низкие значения элювиально-аккумулятивных коэффициентов большинства металлов в изученных почвах плоскогорья могут служить показателем отсутствия на данный момент здесь выраженного антропогенного загрязнения. Содержание большинства элементов в почвах увеличивается c глубиной. В горно-тундровых торфянистых почвах под ерником обнаружена биогенная аккумуляция Mn. Для степных почв отмечено некоторое накопление в поверхностных горизонтах Zn, Cr, V и Ni. Наиболее равномерным распределением отличается Pb и Zn. Исходная неоднородность моренных и озерно-ледниковых отложений определяет разнообразие внутрипрофильного распределения металлов в почвах, на них сформированных. Не выявлено четкой зависимости содержания большинства макро- и микроэлементов в поверхностных водах от уровня их концентраций в почвах. Тем не менее отмечено повышение интенсивность водной миграции железа в заболоченных ландшафтах Бертекской части бассейна реки Ак-Алаха, в водах которой обнаружено его наиболее высокое содержание.

ОПРЕДЕЛЕНИЕ НИЗКИХ СОДЕРЖАНИЙ (МЕНЕЕ 0,0005% (ПО МАССЕ)) МЫШЬЯКА В НИКЕЛЕВЫХ СПЛАВАХ МЕТОДАМИ ИСП-МС И ААС С ЭЛЕКТРОТЕРМИЧЕСКОЙ АТОМИЗАЦИЕЙ

In this work, the determination of low contents (less than 0,0005 wt. %) of arsenic in complex alloyed samples of nickel alloys was carried out by means of inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry with electrothermal atomization. Also, the ICP-MS method was used to determine the arsenic content in chromium, which is an alloying component of nickel alloys. A technique for dissolving a sample and preparing it for analysis is presented. Spectral interferences are eliminated by applying mathematical correction equations, a reaction-collision cell and using corrective additives. The correctness of the results obtained is confirmed by the analysis of certified reference materials of nickel alloys and chromium.

ВЛИЯНИЕ БИОГЕОХИМИЧЕСКОЙ ОБСТАНОВКИ ВОДОСБОРНЫХ БАССЕЙНОВ НА МИКРОЭЛЕМЕНТНЫЙ СОСТАВ ВОД ПРИТОКОВ ТЕЛЕЦКОГО ОЗЕРА

Introduction. The formation of the microelement composition of surface waters in reservoirs and watercourses is determined by the biogeochemical processes in the catchment area. However, the schemes and mechanisms of interaction between watercourses and the soils drained by them have been studied insufficiently. Lake Teletskoye is the largest water reservoir of Altai, one of the deepest lakes in Russia, and its catchment area is 90 times larger than the area of the lake itself. Methods. We collected water samples in Lake Teletskoye tributaries during the summer low water period, in the estuaries of rivers. The ionic composition of waters and water extracts from soils (1:5) was determined using standard methods with a titrimetric finish. The content of trace elements (Cd, Cu, Fe, Mn, Ni, Zn, Pb, Cr, Co, V) in filtered water samples, suspended water matter and water extracts from soils was determined by atomic absorption spectrometry using electrothermal atomization on a SOLAAR M6 device. Results. The article presents the results of macro - and microelement composition studies of Lake Teletskoye tributaries’ waters. It is shown that the waters of the studied tributaries are characterized by a low total content of the main salt composition components. A dependence of the content and distribution of trace elements in the “water – suspended matter” system on the catchment landscape and geochemical features was found. Conclusion. The content of the water-soluble forms of Cd, Cu, Fe, Mn, Zn, Pb, Co, V in Lake Teletskoye tributaries’ waters conforms to environmental and sanitary requirements. It was found that Fe, Zn and Cr migrate mainly as the soluble compounds, while Pb, Mn, Cu migrate mainly in suspension. It was revealed that the different soil cover structure of the eastern and western lake shores determines different conditions for the hydrochemical flow formation of their rivers and, as a result, forms the differences in the physical and chemical composition of the eastern and western tributaries’ waters.

Estimation of the Seasonal Variability of the Content of Heavy Metal Compounds in the River Waters of the Foothill Zone of the Central

Based on long-term data, the seasonal variability of the content of heavy metal compounds in the water of the rivers of the foothills of the Central Caucasus – the Terek, Malka, Baksan, Ardon, Cherek, and Urukh – was estimated.Generalizing studies affecting the regional characteristics of the level of hazardous heavy metals in the river waters of the foothill zone of the Central Caucasus have not been carried out over many years. Therefore, the objective of the study was to assess the level of hazardous compounds of heavy metals (Cr, Ni, Mo, Mn, Zn, Pb) in the water of the Terek, Malka, Baksan, Ardon, Cherek and Urukh rivers at 6 observation points located in the foothill zone of the Central Caucasus, for the period from 2005 to 2018. In the analysis, the atomic absorption method using the MGA-915M electrothermal atomizer was used. The level of heavy metal compounds in river water was evaluated by such characteristics as the long-term average and median concentrations, the range of concentration fluctuations, and the frequency of exceeding the maximum permissible concentration. An analysis of long-term data for the period 2005-2018 on the study of the level of heavy metal compounds in the water of the Baksan, Malka, Urukh, Terek, Cherek and Ardon rivers in the foothill zone of the Central Caucasus shows that river water pollution to a greater extent occurs in summer rain flood . The revealed levels of heavy metal compounds in river water over the long-term period under study, as well as the frequency of exceeding the maximum permissible concentration, are illustrated by graphs. The results obtained may be relevant in the development of regional water quality indicators.

Оценка сезонной изменчивости содержания соединений тяжелых металлов в речных водах предгорной зоны Центрального Кавказа.

Based on long-term data, the seasonal variability of the content of heavy metal compounds in the water of the rivers of the foothills of the Central Caucasus – the Terek, Malka, Baksan, Ardon, Cherek, and Urukh – was estimated.Generalizing studies affecting the regional characteristics of the level of hazardous heavy metals in the river waters of the foothill zone of the Central Caucasus have not been arried out over many years. Therefore, the objective of the study was to assess the level of hazardous compounds of heavy metals (Cr, Ni, Mo, Mn, Zn, Pb) in the water of the Terek, Malka, Baksan, Ardon, Cherek and Urukh rivers at 6 observation points located in the foothill zone of the Central Caucasus, for the period from 2005 to 2018. In the analysis, the atomic absorption method using the MGA-915M electrothermal atomizer was used. The level of heavy metal compounds in river water was evaluated by such characteristics as the long-term average and median concentrations, the range of concentration fluctuations, and the frequency of exceeding the maximum permissible concentration. An analysis of long-term data for the period 2005-2018 on the study of the level of heavy metal compounds in the water of the Baksan, Malka, Urukh, Terek, Cherek and Ardon rivers in the foothill zone of the Central Caucasus shows that river water pollution to a greater extent occurs in summer rain flood . The revealed levels of heavy metal compounds in river water over the long-term period under study, as well as the frequency of exceeding the maximum permissible concentration, are illustrated by graphs. The results obtained may be relevant in the development of regional water quality indicators.

Lead and cadmium in conventional and organic carrots

AbstractToxic elements like lead and cadmium are considered harmful to human health. These elements do not have any useful function in an organism. They are known only for their negative actions, which can be tolerated by human body only in certain limits. Carrots may absorb these toxic elements from the soil they grow in. The presence of the contaminants depends mainly on the mode and site of cultivation, fertilizer, industrial infrastructure, level of transportation and roads around cultivation site or occurrence of municipal and agricultural waste nearby. The organic food is supposed to be healthier due to, among other things, less content of toxic substances, which results from more sustainable farming. The aim of this research was to determine the content of lead and cadmium in carrots from conventional and organic farming that were available on polish market.The research had been conducted for two years. Both kinds of carrots had been purchased at the same time in different supermarkets in Poland. Altogether, 36 packages, both conventional and organic carrots, were collected. The samples of carrots were dried and then reduced to ashes in 480 °C within few hours. Then the residues were dissolved in 1 M nitric acid and quantitatively transferred to measuring flasks, complemented with deionised water. The content of cadmium and lead was determined by application of electrothermal atomizer (graphite furnace) in iCE 3000 (Thermo Scientific, USA) spectrometer using adequate cathode lamps and Zeeman background correction. Wavelengths for analysis of lead and cadmium were 217 nm and 288.8 nm respectively.The results show that there are statistically significant differences in the average content of lead and cadmium in conventional and organic carrots. The concentrations of lead in conventional and organic carrots were 0.0192 mg kg-1 and 0.0118 mg kg-1 respectively. The concentrations of cadmium in conventional and organic carrots were 0.0050 mg kg-1 and 0.0023 mg kg-1 respectively.The research indicates that toxic elements like Pb and Cd are present in both types of carrots, but their amount is lower than permissible concentrations established by EU ordinance. The conducted experiments also showed that the content of Pb and Cd in organic carrots is lower than in the conventional ones. This may be resulted in the differences in farming.

Determination of Pb (II), Cu (II), Co (II), Mn (II), and Fe (III) by electrothermal atomization atomic absorption spectrometry after preconcentration with nanofibers

The results of sorption preconcentration of some heavy metal (HM) ions with their subsequent determination in natural and drinking water by electrothermal atomization atomic absorption spectrometry (ETAAS) are presented. The sorption and desorption (0.01 – 1 M HNO3) of lead, copper, iron, cobalt and manganese ions from aqueous media on nanofiber samples obtained from polyacrylonitrile (PAN) with subsequent directed modification by 1.25 M NaOH solution upon heating (70°C) (PAN*) are studied and optimized. Nanofibers were obtained by capillary-free electroforming from solutions of PAN in dimethylformamide. This method is advantageous for the simplicity of equipment, high energy efficiency of nanofiber production, versatility and flexibility in controlling process parameters and allows production of nanomaterials with desired properties. The values of the extraction degree (95.8 – 99.5%) and selectivity coefficients for competing pairs of metal ions are calculated: вPb/Cu = 1.2; вPb/Co = 2.8; вPb/Mn = 3.2;вCu/Co = 1.7; вCu/Mn = 3.7; вCo/Mn = 2.5. A comparative analysis of the sorption activity of the obtained nanofibers revealed that the character of lead, copper, cobalt and manganese ion sorption by nanofibers is non-selective at pH 6 – 8 and selective for iron (III) ions at pH  3. A technique of sorption-atomic absorption determination of the aforementioned metal ions in real objects with preliminary nanofiber concentration at the level of tenths and hundredths of MPC is proposed. Non-woven materials based on modified PAN are used as effective extractants of nanogram quantities of HM ions. The detection limits for heavy metal ions are 40 – 80 ng/dm3.

Preconcentration of Pb with Aminosilanized Fe3O4 Nanopowders in Environmental Water Followed by Electrothermal Atomic Absorption Spectrometric Determination

A new preconcentration method to determine lead in environmental waters using the aminosilanized magnetite Fe3O4 powder sorbent has been developed. The preconcentration method was combined with electrothermal atomization atomic absorption spectrometry (ETAAS) and a graphite atomizer. Trace amount of sorbent (3 mg) could be applied into the preconcentration of Pb. According the preconcentration, the detection limits were 14 and 19 pg·mL−1 with bare and aminosilanized Fe3O4, respectively. The effect of interferent elements such as Al, Ca, Co, Fe, K, Mg, Na, Ni, and Zn (1000 ng·mL−1 versus Pb 1 ng·mL−1) on the preconcentration of Pb using bare magnetite was evaluated, and some elements (Al, Ni, and Zn) were found to interfere with the Pb preconcentration. The aminosilanized Fe3O4 sorbent was found to be effective in eliminating the severe interferences. The enrichment factors were 34 for the preconcentration with aminosilanized Fe3O4. The recovery of spiked Pb in the case of the sorbent with aminosilanized Fe3O4 was in the range of 75 to 110%. From the analytical data, the preconcentration technique was found to be useful for the determination of trace lead in environmental waters.

IS LEAD A REMARKABLE COMPONENT IN RESISTANT HYPERTENSION? RESULTS FROM A STUDY IN PATIENTS OF A SPANISH HYPERTENSION UNIT

Objective: Lead is a toxic element that represents a public health problem and that could be not only a risk factor for hypertension (HT) but might contribute to the development of resistant hypertension (rHT). AIMS: The aims of this study were to describe and compare the blood lead levels in a group of subjects - from a hospital hypertension unit - with resistant hypertension and non-resistant hypertension and to define a blood lead threshold related to resistant hypertension. Design and method: Cross-sectional study. Resistant hypertension was defined according to the European Society of Hypertension (ESH). Obesity was defined as body mass index (BMI) >30 kg/m2. Creatinine clearance was obtained from 24 hour urine. The blood lead concentration was measured by electrothermal atomization atomic absorption spectrometry with Zeeman background correction in a Perkin-Elmer spectrometer Analyst 800. Results: We included 73 hypertensive subjects (men: 46.6 %), 44 (61.7 %) were rHT cases. Age: HT: 57.7, rHT: 61.7 y (p = 0.06). Blood pressure: HT: 132.5 ± 15.4/75.8 ± 8.5, rHT: 155.6 ± 23.5/82.45 ± 11.9 mmHg (p < 0.05). BMI: HT: 30.2 ± 3.9, rHT: 31.7 ± 6.6 kg/m2 (p = 0.236). Glucose: HT: 107.1 ± 21.1 vs. rHT: 121.5 ± 46.3 mg/dl (p = 0.077). Creatinine clearance: HT: 90.7 ± 25.85, rHT: 74.6 ± 26.2 ml/min, p = 0.013. Blood lead median: HT: 3.7 (IQR 2.7–5.1), rHT: 3.7 (IQR 2.8–6.1) microg/dl (p = 0.885). Multiple step logistic regression analysis including a blood lead threshold > 5.5 microg/dl (75th percentile) and adjusting for age, obesity and creatinine clearance showed: OR 4.29 (1.07 ± 17.16, p = 0.04) to rHT Conclusions: Subjects with a blood lead threshold of >5.5 microg/dl have a higher risk for resistant hypertension independently of age, obesity and creatinine clearance

Desarrollo y optimización de una metodología para la determinación de metales y semimetales en cabello

Hair is an alternative biological matrix widely used in biomonitoring programs. It is used as a biomarker of chronic exposure to environmental contaminants and to evaluate pathologies related to the excess or shortage of certain substances. Hair is a complex matrix for the evaluation of toxics in low levels. This matrix is an analytic and pre-analytic challenge. In this work, the development and validation of a methodology for the determination of mercury (Hg), lead (Pb), arsenic (As) and manganese (Mn) by atomic absorption spectrometry is presented. The sample treatment was carried out by microwave assisted digestion. The determination of Hg was carried out using cold vapor (CV-AAS) and hydride generation (HG-AAS) was used for As. Mn and Pb were analyzed by electrothermal atomization (ET-AAS). The figures of merit evaluated were linear range, limits of quantification and detection, accuracy at three levels and veracity. The latter was evaluated using a hair reference material (No. 13 Human Hair, from the National Institute of Environmental Studies (NIES), Japan). The validation of this methodology is very useful for the study of exposure to these analytes, because of the simplicity of sample obtention.

Features of Microelements Express-determination in Medicinal and Nonoficinal Plants by X-Ray-Fluorescence Analysis

Introduction. The chemical composition of plants depends on the elemental composition of the habitat, and also reflects the species and individual characteristics of the plant. Before using any plant for medicinal purposes, it is also necessary to collect as much information as possible about the elemental composition of the feedstock.Aim. Consequently, it became possible to create a method for the rapid determination of trace elements in plants using the X-Ray fluorescent method.Materials and methods. In accordance with the international intercalibration standard in the IAEA system (IAEA-433), an international standard sample NIST SRM 2976, certified by the National Institute of Standards and Technology (USA), was used to provide external quality control (QA/QC) of laboratory elemental analysis. For Zn the results of plant raw powder materials analysis by XRF (express analysis) were compared with AAS by electrothermal atomization and Zeeman background correction after microwave acid mineralizationof biomaterials. To ensure the reproducibility of the results of XRF-express analysis, it is absolutely necessary to carry out mild drying and dispersion of the plant material.Results and discussion. The results of X-ray fluorescence (XRF) analysis of the elemental composition of the fruits (fructus Anethi graveolens L.), the seeds (semina Cucurbitae pepo L., semina Menthae arvensis L., semina Cucumis sativa L., semina Kalanchoës daigremontianae) and leaves (folia Callisiae fragrantis L.) of medicinal and nonoficinal plants are presented in the article. The methods of XRF and AAS analysis have been developed for the technology of essential micoelements enrichment in of Callisiae fragrantis control leaves at different ratios of hydrogen isotopologues (D/H) in the water.Conclusion. For example, zinc(II) has demonstrated the ability to create modified plants with high content of essential microelement, up to 1.4 mg /g dry weight.

Atomic Absorbance Spectroscopy to Measure Intracellular Zinc Pools in Mammalian Cells.

Transition metals are essential micronutrients for organisms but can be toxic to cells at high concentrations by competing with physiological metals in proteins and generating redox stress. Pathological conditions that lead to metal depletion or accumulation are causal agents of different human diseases. Some examples include anemia, acrodermatitis enteropathica, and Wilson's and Menkes' diseases. It is therefore important to be able to measure the levels and transport of transition metals in biological samples with high sensitivity and accuracy in order to facilitate research exploring how these elements contribute to normal physiological functions and toxicity. Zinc (Zn), for example, is a cofactor in many mammalian proteins, participates in signaling events, and is a secondary messenger in cells. In excess, Zn is toxic and can inhibit absorption of other metals, while in deficit, it can lead to a variety of potentially lethal conditions. Graphite furnace atomic absorption spectroscopy (GF-AAS) provides a highly sensitive and effective method for determining Zn and other transition metal concentrations in diverse biological samples. Electrothermal atomization via GF-AAS quantifies metals by atomizing small volumes of samples for subsequent selective absorption analysis using wavelength of excitation of the element of interest. Within the limits of linearity of the Beer-Lambert Law, the absorbance of light by the metal is directly proportional to concentration of the analyte. Compared to other methods of determining Zn content, GF-AAS detects both free and complexed Zn in proteins and possibly in small intracellular molecules with high sensitivity in small sample volumes. Moreover, GF-AAS is also more readily accessible than inductively coupled plasma mass spectrometry (ICP-MS) or synchrotron-based X-ray fluorescence. In this method, the systematic sample preparation of different cultured cell lines for analyses in a GF-AAS is described. Variations in this trace element were compared in both whole cell lysates and subcellular fractions of proliferating and differentiated cells as proof of principle.

Direct Determination of Lead in Sea Water by High-Resolution Atomic Absorption Spectroscopy Using a Mixed Modifier Barium Nitrate–Hydrofluoric Acid

A procedure is proposed for the direct determination of lead in sea water by electrothermal atomization high-resolution atomic absorption spectrometry. The effect of background interferences due to sea water matrix is eliminated using a mixed modifier barium nitrate–hydrofluoric acid. The optimum amount of the modifier matrix is 60 µg Ba (NO3)2 + 1.52 µg HF. The conditions of analysis are as follows: pyrolysis temperature 600°C, atomization temperature 1200°C. The limit of detection for the developed procedure is 0.0003 mg/L.

A green on-line digestion system using 70% hydrogen peroxide and UV radiation for the determination of chromium in beer employing ETAAS

This work proposes an on-line digestion system employing 70% (w/w) hydrogen peroxide and UV radiation for producing hydroxyl radicals for the determination of chromium in beer samples by electrothermal atomization atomic absorption spectrometry (ETAAS). The digester system consists of a closed wooden box, which is painted black internally, containing a PTFE tube wrapped around a 15 W UV lamp. During the mineralization step, a peristaltic pump is employed to propel the sample solution over the UV lamp. The experimental factors UV irradiation time and hydrogen peroxide volume were optimized using a two-level full factorial design. Degradation curves at different pH conditions demonstrated that the digestion of beer is faster at alkaline pH. The results demonstrated that, in the presence of 70% H2O2 and 15 W UV radiation, 75% of the chromophore species is degraded with an irradiation time of 25 min. The degradation kinetic curves of beer samples under different conditions were also evaluated. The apparent kinetic constant (kapp) found for the process assisted by 70% H2O2 and 15 W UV light was 0.0668 min−1 (R2 = 0.9936). The on-line digestion procedure with a sample flow rate of 2 mL min−1 for 45 min allowed the determination of chromium in beer samples by ETAAS, utilizing the external calibration technique, with the analytical line 357.9 nm, in the presence of magnesium as chemical modifier with limits of detection and quantification of 0.86 and 2.90 μg L−1, respectively. The method accuracy was confirmed by the analysis of the certified reference material of ERM-CA713 wastewater provided by the European Reference Materials. Six beer samples were digested and the chromium was determined. The contents found varied from 4.26 to 33.28 μg L−1. Addition/recoveries tests were also performed to evaluate the accuracy method. The recoveries obtained varied from 93.2 to 96.4%.

High-speed spectral pyrometer based on a «Kolibri-2» spectrometer

The operation speed of commercially available spectral-ratio pyrometers and brightness pyrometers often appears insufficient for control of fast-changing temperature (e.g., in a graphite cell of an AES electrothermal atomizer, the rate temperature change is 104°C/sec). An advantage of spectral pyrometers is high speed and ability to measure the temperature of objects with unknown emissivity. The goal of this study is to develop a high-speed spectral pyrometer based on a «Kolibri-2» spectrometer with BLPP-2000 photodetector array that provides a wide working wavelength range 400 – 1050 nm, and minimum basic exposure time of 0.4 msec. The temperature was calculated by plotting the emission spectrum of the object in Wien coordinates (with allowance for calibration of the spectral pyrometer using radiation source of the known temperature) and measuring slope of the obtained graph. The relative error of temperature measurements on a spectral pyrometer estimated by comparing measurement results and data obtained with a calibrated Termokont-TN5S1M (Termokont company) single-channel pyrometer was not more than 1.5% in a temperature range of 1000 — 2400°C and higher, and rapidity up to 2500 measurements/sec. The results of measuring temperature of the graphite cell of the electrothermal atomizer using a spectral pyrometer during sample atomization at a rate of temperature change up to 10 000°C/sec are presented.

Simultaneous multi-element determination in electrothermal atomic-absorption spectrometry with electrothermal atomization

A discussion of the prospects for creating a multi-element atomic absorption (AA) spectrometer leads to the conclusion regarding the expediency of using spectral devices of relatively low resolution. Previous studies showed that the spectrometer with instrumental bandwidth 0.12 nm equipped with a CCD detector could provide the absorption measurements within a wavelength range of 200 – 400 nm using low-noise radiation sources, e.g., deuterium or low current xenon lamps. The rate of data acquisition was sufficient for vapour spectra monitoring during the pulse atomisation in graphite furnace atomizer. The loss in sensitivity due to low resolution is compensated by the possibility of direct determination of several elements in a single liquid or powder sample. Feasibility of multi-element simultaneous AA spectrometry depends on the efficiency of atomization technique and technology of data processing. The concurrent problems are discussed by the example of new calculation algorithm and its application to the analysis of multi-element nitrate and halogen containing reference materials. It is shown that linearization of the calibration curves for about 10 – 15 elements, which are not subject to chemical impacts, can be carried out automatically in a concentration range up to 4 – 5 orders of magnitude with 5 – 10 % deviation from the linearity at the ends of the interval. For the elements forming stable molecular compounds further improvement of the atomization technique is required.

Safety Assessment of the Trace Element Impurities Ni and Cr in Pharmaceutical Herbal Products for Teething from Polish Pharmacies.

Control of elemental impurities (EIs) in pharmaceutical herbal products is currently important but not a very popular topic in modern toxicological analysis. The occurrence and concentration of EIs in the pharmaceutical herbal products should be controlled and meet the standards of directive International Conference on Harmonisation's Q3D Guideline on Elemental Impurities. An interesting area of interest is measuring EIs including toxic and allergic metals in pharmaceutical herbal products for teething. The aim of this article was determination of Ni and Cr impurities in pharmaceutical herbal products for teething available in Polish pharmacies. Justifications were (1) herbs as an important source of EIs and (2) infants may be particularly sensitive to the toxic effects of metals because they tend to absorb a higher fraction of an oral dose. The analysis was carried out using microwave-assisted wet digestion with concentrated nitric acid and electrothermal atomisation atomic absorption spectrometry. The safety assessment involved a triple approach: (1) level of Ni and Cr impurities in pharmaceutical samples; (2) level of Ni and Cr impurities including one-time administration of teething gels and (3) daily intake of metals. In all three cases, the results indicate that the standards of directive ICH Q3D are met for Ni and Cr. Overall, it can be concluded that none of the teething gels represents a health hazard to infants.

High-resolution continuum-source electrothermal atomic absorption spectrometer for simultaneous multi-element determination in the spectral range of 190–780 nm

We have built a prototype atomic absorption spectrometer with an electrothermal atomizer and continuum light source for simultaneous multi-element determination.