Hydride Generation Technique Research Articles

Rice Water—More a Source of Nutrition Elements or Toxic Arsenic? Multi-Element Analysis of Home-Made (Natural) Rice Water and Commercialized Rice-Based Products Using (HG)-ICP OES

Although rice is a well-known source of nutrients, it unfortunately accumulates As the most compared to other cereal plants. Due to the growing interest in rice-based cosmetics, the aim of the work was the multi-element analysis of various home-made (natural) rice waters and commercialized ready-to-use rice-based cosmetics for skin/hair. The total concentrations of Al, As Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Zn in raw rice and rice products were determined using inductively coupled optical emission spectrometry (ICP OES) after wet sample decomposition in the presence of concentrated HNO3. In the case of As, the hydride generation (HG) technique was used as a sample introduction system to the ICP OES instrument. Five different procedures, including washing/rinsing, soaking, boiling, and fermentation steps, and three rice types, i.e., white, brow, and jasmine, were used for this purpose. The effects of the water temperature, the contact time of rice grains with water, and the type of rice on the water-soluble concentrations of elements were examined and compared. A significant difference in the solubility of elements was observed depending on the type of rice, with the lowest percentage of extraction noted for brown rice. The best option was soaking unwashed rice grains in a six-fold excess of cold water for 30 min. The selection criterion was to preserve the highest content of essential elements (Ca (0.76–1.2 mg kg−1), Cu (9.2–43 ng k−1), Fe (0.096–0.30 mg kg−1), Mg (6.9–11 mg kg−1), Mn (0.16–10.32 mg kg−1), and Zn (0.083–0.25 mg kg−1)) with reduced to a minimum As level, i.e., <5 ng g−1 (2.8–4.8 ng g−1), making this water safe for consumption. In contrast, regularly drinking water after boiling or soaking rice grains in hot water carries the risk of consuming an excessive amount of this element due to As content exceeding the permissible value, i.e., 10 ppb. Finally, these home-made products were compared with commercialized cosmetics for skin/hair, with satisfactory results.

Determination of Arsenic Species Distribution in Arsenide Tailings and Leakage Using Geochemical and Geophysical Methods

This study describes the distribution of arsenic mobile species in the tailings of Cu–Co–Ni–arsenide using the sequential extraction and determining the contents of arsenate (AsV) and arsenite (AsIII). The object of this study is the tailings ponds of the Tuvakobalt plant, which contains waste from the hydrometallurgical arsenide ore processing of the Khovu-Aksy deposit (Republic of Tuva, Russia). A procedure of sequential extraction for arsenic was applied, and it includes the extraction of the following forms: water-soluble, potentially water-soluble and exchangeable, easily sorbed on the surface of carbonates, associated with Fe/Mn oxides/hydroxides, associated with easily oxidized minerals, and accounted for by non-oxidized arsenic minerals. This procedure, which takes into account the peculiarities of the physical and chemical composition of the waste, was supplemented by the analytical determination of the arsenite and arsenate content by using the methods of inductively coupled plasma atomic emission spectrometry (ICP-AES) combined with the hydride generation technique (HG-ICP-AES). The content of the most mobile forms of arsenic, which are water-soluble, potentially water-soluble, and exchangeable species, is equal to 56% of the total arsenic content, 23% and 33% of which are arsenite and arsenate, respectively. Unlike arsenic, the mobile forms of metals have been determined in small quantities. The largest proportion of water-soluble and exchangeable forms is formed by Mg, Ca, and Sr at 11, 9.4, and 20%, respectively (residual and redeposited carbonates). The proportion of water-soluble forms of other metals (Cu, Zn, Co, and Ni) is < 1% or 0. The main part of the metals is adsorbed on the surface of Fe and Mn hydroxides, enclosed in easily and hardly oxidized minerals. In addition to geochemical studies, the presence of leaks from the tailing ponds into ground waters was determined by using electrical resistivity tomography. The data obtained indicate a high environmental hazard of tailings and the possibility of water-soluble and highly toxic arsenic compounds entering ground waters and aquifers.

Trimethylselenonium ion determination in human urine by high-performance liquid chromatography-hydride generation-atomic fluorescence spectrometry optimization of the hydride generation step.

This work describes the intricacies of the determination of the trimethylselenonium ion (TMSe) in human urine via high-performance liquid chromatography-hydride generation-atomic fluorescence spectrometry (HPLC-HG-AFS). By definition, this technique requires that the separated TMSe can be online converted into a volatile compound. Literature data for the determination of TMSe via the hydride generation technique are contradictory; i.e., some authors claim that direct formation of volatile compounds is possible under reduction with NaBH4, whereas others reported that a digestion step is mandatory prior to conversion. We studied and optimized the conditions for online conversion by varying the mobile phase composition (pyridine, phosphate, and acetate), testing different reaction coils, and optimizing the hydride generation conditions, although technically no hydride (H2Se) is formed but a dimethylselenide (DMSe). The optimized conditions were used for the analysis of 64 urine samples of 16 (unexposed) volunteers and the determination of low amounts of TMSe (LOD = 0.2ngmL-1). Total (specific gravity-corrected) selenium concentrations in the urine samples ranged from 7.9 ± 0.7 to 29.7 ± 5.0ngmL-1 for individual volunteers. Four volunteers were characterized as TMSe producers (hINMT genotype GA) and 12 were non-producers (hINMT genotype GG). Urine of TMSe producers contained 2.5 ± 1.7ngmL-1 of TMSe, compared to 0.2 ± 0.2ngmL-1 for non-producers.

Chemometric classification and discrimination of herbal dietary supplements based on ICP-MS elemental profiling

This study presents the determination of elemental profiling of representative dietary herbal supplements which were purchased on the Croatian market in the forms of capsules, powders, jams or liquids. Using inductively coupled plasma mass spectrometry (ICP-MS), twenty-four elements in eighty-seven different samples were determined. Electrothermal atomic absorption with hydride generation technique (HG-ETAAS) applied for the selenium determination in all samples gave the similar results as ICP-MS technique. Elemental profiling resulted with determination of major constituents Na, Mg, Ka and Ca with mean concentration values of 2900, 2700, 9200, and 16,600 mg kg−1, respectively. Elements of middle concentration range were: B, Al, Mn, Fe, Zn and Sr (31.8–1050 mg kg−1). Trace and ultra-trace levels comprise of Se, V, Cr, Co, Ni, Cu, As, Mo, Cd, Sb, Hg, Tl and Pb (21.7–11,300 µg kg−1). Using PLS-DA statistical analysis, the elements Se, Na, Fe, Co, Tl, and Zn, were established as the marker elements with the greatest discriminating power between supplement samples. Multivariate PCA analysis resulted with the successful discrimination of Se and Zn enriched supplements. Hierarchical cluster analysis (HCA) enhanced the recognition of similarities in sub-clusters of samples. Minor discrepancies in trace and ultra-trace elemental profiles revealed Hg, As, Cd, Pb, Cr and Co as the key elements for discrimination between two groups of Ayurvedic and spirulina-based supplements. The HCA method also allowed visualization of the exceptional elemental profile of several mixed-herb supplements. There were distinctive features of herbal dietary supplements with peculiar influences of botanical, environmental and/or production conditions on their elemental profile.

ICP-spectrometric determination of the total tin content in the water of the Azov and Black seas using the hydride generation technique

The current paper considers the possibility of determining the total tin content in the waters of the Azov and Black seas using the hydride generation technique. The conditions for the generation of tin hydrides were optimized for the subsequent determination by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). When studying the matrix effect of the components, it was found that the transition metals Ni2+, Co2+, Cu2+, and Fe3+ reduce the analytical signal of tin. The possibility of leveling the influence of transition metals by various binding masking agents (L-cysteine, EDTA, tartaric acid, potassium iodide and thiocarbamide), of which L-cysteine showed the greatest efficiency, was studied. Under the optimized analysis conditions, the limits for the determination of inorganic tin in the model waters were established, which, regardless of the salinity level, were 0.05 and 0.03 μg/dm3 for ICP-AES and ICP-MS, respectively. The possibility of determining tin in waters using the hydride generation technique, when the analyte was present in the form of organotin compounds, was evaluated. It has been shown that for the ICP spectrometric determination of the analyte with the generation of hydrides in water containing organotin compounds, microwave mineralization of the samples was required. The satisfactory convergence of the analyses’ results was observed when determining the total content of tin in sea waters in the concentration ranges of 0.05–2.00 and 0.03–2.00 μg/dm3 for ICP-AES and ICP-MS, respectively. The developed methods were used to determine tin in the waters of the Azov and Black seas; the total analyte content in them was 0.15 and 0.23 μg/dm3­, respectively.

Concentrations of mercury and other elements in ewes’ milk: Effect of lactation stage

There is an increased production and demand for ewes’ milk in the Republic of Croatia, as well as globally. There is also a growing concern about its quality, since milk from farm animals may become contaminated with mercury and other toxic elements. Thus, the aim of this paper is to determine the influence of lactation stage on the ewes’ milk quality in western Croatia by considering concentrations of mercury and other elements in ewes’ milk. The research was conducted on 36 Travnik pramenka sheep during different lactation stages. The digested milk samples were analysed with continuous flow hydride generation technique by using inductively coupled plasma mass spectrometry. Samples were taken during 40th, 80th and 120th d of lactation. Yield and quality of ewes’ milk was within lactation curve. As lactation progressed, significantly lower concentrations of Hg (on 80th d compared to 40th d) and of Cd (120th d compared to 80th d) were noted, and Hg on 120th d was below the detection limit. Concentrations of Ca and Cu were lower on the 120th d compared to 40th d, while P, Mg, Fe, Zn, Mn, and Se were lower on the 80th and 120th d compared to the 40th d. Concentrations of K, Mo, and Cr differed among all stages of lactation. Regarding toxic elements, the observed low concentrations of Hg, Co, Cd and As suggest that ewes’ milk in western Croatia is safe for human or animal consumption.

On the coupling of hydride generation (HG) with flowing liquid anode atmospheric pressure glow discharge (FLA-APGD) for determination of traces of As, Bi, Hg, Sb and Se by optical emission spectrometry (OES)

A novel atmospheric pressure glow discharge (APGD) microplasma system, sustained between a miniaturized flowing liquid anode (FLA) and a He jet nozzle cathode, was combined with a hydride generation (HG) technique to improve the determination performance of As, Bi, Hg, Sb, and Se with the aid of optical emission spectrometry (OES). The discharge current, the He flow rate, and the concentrations of HCl and NaBH4 were considered to affect both the HG reaction and the excitation conditions in the discharge, thus they were thoroughly studied. Under the optimized conditions, the detections limits (LODs), assessed on the basis of the 3σ criterion, reached 1.7, 0.85, 0.04, 0.51, and 2.9 μg L−1 for As, Bi, Hg, Sb, and Se, respectively. The HG and transport efficiency for these elements was evaluated to be 88–100%, which is notably better, as compared to their transport efficiency in the conventional FLA-APGD system, without the HG technique. This yielded an improvement of the LODs achievable in this system and, simultaneously, enabled to determine As, Sb, and Se at a level, which is unobtainable with the use of the FLA-APGD system alone. The proposed methodology was then successfully applied for a quantitative determination of the examined elements in wastewater (ERM-CA713) and spiked water samples. The recoveries of the elements added to these waters (at the maximum acceptable levels in drinking water set by the U.S. Environmental Protection Agency) ranged between 81 and 104%, confirming the excellent accuracy, usefulness, and reliability of the developed HG-FLA-APGD technique.

A Novel Online Hydride Generation Technique for the Simultaneous Determination of Ultra Trace Amounts of Hydride Forming Elements in Water Samples by Inductively Coupled Plasma Optical Emission Spectrometry

A simple and rapid online hydride generation technique based on ultrasonic nebulizer was applied for the first time for the simultaneous determination of trace amounts of As, Bi, Sb, Se and Te by inductively coupled plasma optical emission spectrometry. In this method, we used an ultrasonic nebulizer as a hydride generator and sample introducer simultaneously. An ultrasonic nebulizer was applied for the online hydride generation technique without using any device, such as a gas phase separator, which is mandatory in the classic hydride generation method. This technique improved method detection limit comparing to the traditional hydride generation system which is a necessity in the ultra-trace determination of hydride forming elements. The developed technique shows an improvement factor ranging from 56 to 450 times in detection limits in comparison to a concentric nebulizer. The obtained detection limits were well below the maximum concentration limit. The practical applicability of the developed method was examined using natural water samples.

Determination of chalcophile elements in sulfide-bearing rocks by hydride generation inductively coupled plasma optical emission spectrometry and inductively coupled plasma mass spectrometry

Inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry with the preliminary hydride generation (HG-ICP-OES) techniques were used for the determination of chalcophile elements in sulfide-bearing rocks after different sample pretreatment. As and Se in the hydrochloric acid leaching solutions could not be determined neither by quadruple MS with correction equations, no by high resolution (HR-MS) (R = 10,000) due to high СHCl/СAs,Se ratio. Se, Sn, Ga, Bi, Te, Sb, Ge, Cd, Tl and Pb in hydrochloric acid leaching solutions can be determined by ICP-MS, and As, Se, Sn, Bi, Te and Sb by HG-ICP-OES. Main matrix elements - Co, Ni, Fe, Cu – don't affect the signal of analytes in case of ICP-MS method. The matrices of the sulfide ores and rocks were shown to significantly suppress the signals of the all elements using HG-ICP-OES techniques. To eliminate the influence of matrix components, the use of auxiliary reagents – 5% (m/V) KI and 0.5% (m/V) ascorbic acid C6H8O6 as well as 5% (m/V) KBr – has been proposed. Optimal conditions for obtaining the hydrides and for the determination of hydride-forming elements by HG-ICP-OES were established. Addition of KI and ascorbic acid mixture allows the determination of As, Sn, Bi and Sb. Six elements - Se, Te, As, Sn, Bi and Sb could be determined in the presence of 5% (m/V) KBr.The Сmin values for the determination of these elements by ICP-MS and HG-ICP-OES methods are comparable and vary between 0.01 and 0.02 μg g−1 for As, Se, Sb and Bi, and between 0.05 and 0.1 μg g−1 for Sn and Te.

On-line determination of ultra-trace of antimony species via hydride generation technique using ultrasonic nebulization system coupled to ICP-OES

A fast, sensitive, and on-line hydride generation method using ultrasonic nebulizer was applied for the determination of Sb(III) and Sb(V) by inductively coupled plasma-optical emission spectrometry (ICP-OES). In the proposed technique, an ultrasonic nebulizer was used for on-line and direct hydride generation as well as for sample introduction into the ICP-OES. The Sb(III) could be selectively determined by introducing the mixture of sample and reductant solutions directly into the ultrasonic nebulizer. The concentration of Sb(V) was calculated by the difference between total Sb and Sb(III). The effects of different experimental parameters on the performance of the method were studied. Under the optimum conditions, the limits of detection 0.04 and 0.14 ng mL−1 were obtained for Sb(III) and Sb(V), respectively. The precision of the method, evaluated as the relative standard deviation obtained by analyzing a series of ten replicates, was below 1.7% for both elements. The developed procedure was applied for the determination of antimony species in various water samples.

Potential Health Risk Assessment of Different Heavy Metals in Wheat Products.

In the present work, health risk of heavy metals such as As, Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn in Iranian urban and rural samples including wheat, wheat flour, bread, pasta and sweets were assessed. The real amount of heavy metals in target samples were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and atomic absorption spectroscopy (AAS). Wet ashing and hydride generation techniques were used in sample preparation step. Results demonstrated that heavy metal contaminations in cereal samples were significant. The average concentrations of heavy metals in wheat products were between 0.01 mg kg−1 to 46 mg kg−1. Finally, the health risk assessment results showed that heavy metal contents in rural samples were higher than those in urban samples. The risk of Cu and Zn was significant in two areas and risk of Cr and Cd was not significant.

Use of multiple lines for improving accuracy, minimizing systematic errors from spectral interferences, and reducing matrix effects in MIP OES measurements

Bismuth-based medicines, which are generally available without prescription, are used for a variety of purposes including stomach relief, diarrhea, and cold sores. The determination of Bi in these types of medicines using MIP OES is considered easy, due to the relatively high concentrations of this element. However, high dilution factors can lead to systematic errors and thus low precision. Furthermore, the drugs, excipients, and other active pharmaceutical ingredients (APIs) present in these products can cause spectral and matrix interferences. The present study evaluates the use of multiple spectral lines as a strategy to avoid analytical difficulties. For comparative purposes, hydride generation and standard additions techniques were also evaluated. The results demonstrated the feasibility of using the sum of the intensities of multiple lines to improve accuracy, minimizing systematic errors from spectral interferences and matrix effects, employing simple calculations in a data spreadsheet. The accuracies, calculated based on labeled values, varied from 89.2 to 98.8% and from 72.2 to 124% for direct analysis without and with standard additions, respectively, from 73.2 to 114% for hydride generation, and from 89.8 to 101% for the multiple lines sum method.

Determination of selenium during pathogenesis of hepatic fibrosis employing hydride generation and inductively coupled plasma mass spectrometry.

Serum and liver selenium levels were studied during the pathogenesis of N-nitrosodimethylamine (NDMA) induced hepatic fibrosis in rats. The degree of fibrosis was assessed with Masson's trichrome staining and quantifying collagen content in the liver. Lipid peroxides were measured in blood and liver samples and total glutathione and glutathione peroxidase were assayed in the liver tissue to evaluate oxidative stress. Interleukin-6 (IL-6) and transforming growth factor-β1 (TGF-β1) were measured in the serum. Selenium levels were determined using inductively coupled plasma-mass spectrometry (ICP-MS) after acid digestion and hydride generation of selenium. Serial administrations of NDMA produced well-developed fibrosis and early cirrhosis in the liver with 4-fold increase of total collagen content and deposition of collagen fibers. Blood and hepatic lipid peroxides, serum IL-6 and TGF-β1 were significantly increased. There was significant reduction in hepatic glutathione and glutathione peroxidase levels. Serum and liver selenium were remarkably decreased on all the days studied. The results suggest that decreased selenium and glutathione peroxidase contribute to the impairment of cellular antioxidant defense, which in turn results in oxidative stress and trigger pathogenesis of hepatic fibrosis. The study further demonstrated that ICP-MS with hydride generation technique is a reliable and sensitive method for determination of selenium in biological samples.

Sensitive determination of Se(IV) and tSe in rice and water samples using L-cysteine modified carbon paste electrode-based electrolytic hydride generation and atomic fluorescence spectrometry analysis

This work illustrates an accurate method for determination of Se by electrolytic hydride generation technique based on a novel carbon paste electrode for sample introduction combined with atomic fluorescence spectral analysis. The studies show that Se(IV) can be converted efficiently to SeH2 on an L-cysteine modified carbon paste electrode (CMCPE), which has never been reported before. Significantly, generation from Se(IV) implies that the use of carbon paste electrode-based electron-induced hydride generation system to achieve efficiency is almost 90% to that obtained by chemical hydride generation, and the response obtained from CMCPE is 2 and 3 times of that from the Pb and graphite electrode, respectively. Results also display that the lifetime and the stability of the CMCPE is superior to that of L-cysteine ornamented graphite electrode fabricated by covalently bonding. Under the optimal conditions, a low concentration limit of detection 0.065µgL−1 of Se(IV) is achieved. The repeatability denoted as % RSD is 2.2% for 1.0μgL−1 Se(IV). The utility of the studied method is compared with certified reference materials as well as several edible samples. The advantages and limitations of this method, compared with existing techniques, are also discussed.

Potential of the hydride generation technique coupled to inductively coupled plasma optical emission spectrometry for non-chromatographic As speciation

Selective procedures for determination of As(iii), As(v), DMA and MMA directly by HG-ICP OES were evaluated.

Effect of lactation stage on the concentration of essential and selected toxic elements in milk of Dubrovačka ruda - Croatian endangered breed

The aim of the present study was to determine the lactation stage effect on the concentration of essential and selected toxic elements in the sheep’s milk of Dubrovacka ruda. The research was conducted with 23 sheep, average age of 4 years, of 3rd lactation, while the milk samples were taken during the early (60th day), middle (90th day) and late (120th day) lactation stage. The sheep were selected according to uniformed body development, adequate health status, body condition, equable age (4 years), parity (3rd lactation), stage of lactation (±7 days) and litter size (single). Sheep were reared on the extensive Mediterranean pastures, reared indoors afterwards, fed with hay ad libitum and feed mixtures in average 0.5 kg/day. Milk sample was collected during morning milking from each sheep. The digested samples were analyzed with continuous flow hydride generation technique using inductively coupled plasma for Ca, Mg, K, P, Na, Cu, Fe, Zn, Mn, Ni, Mo, Co, Cr, Cd and Pb concentrations. Significant increase of Mg, Na, Se, Mn, Mo and Cd concentrations were found in milk as well as decrease of K concentration during the lactation. Although the concentration of Ca, Cu, Cr and As in milk during the lactation is increased, the differences between the lactation stages were not observed. Concentrations of P, Fe, Ni, Pb and Hg in milk of Dubrovacka ruda did not differ during the lactation. The low concentrations of Cr, Cd, Pb, As, Hg in milk indicate the safety for consumers and preserved environment of Dubrovnik-Neretva County.

Decomposition of six common selenium species found in animal tissues using microwave digestion with nitric acid and ICP-MS

In this paper we report the decomposition of common selenium species (selenocysteine, selenomethionine, trimethylselenonium ion, selenosugar-1, methyl-2-acetamido-2-deoxy-1-seleno-β-d-glucopyranoside, selenosugar-2, methyl-2-acetamido-2-deoxy-1-seleno-β-d-galactopyranoside and selenosugar-3, methyl-2-amino-2-deoxy-1-seleno-β-d-galactopyranoside) expected to be found in animal tissues and urine using microwave digestion with nitric acid and ICP-MS. Complete decomposition of selenocystine to selenious acid was achieved, selenomethionine and the two selenosugars, were partially degraded to selenious acid and methylseleninic acid while trimethylselenonium ion was not degraded at all. Hydride generation techniques that rely on selenium to be in an inorganic form would have underestimated total selenium in extracts given that these species have different reactivities with borohydride. As trimethylselenonium ion is not degraded, this may lead to the formation of volatile dimethyselenide or dimethyldiselenide during hydride generation and an overestimation of selenium concentration.

Quantitative evaluation for some metal elements in honey from various countries

The analyses of 44 samples of honey, produced in China, Egypt, Ethiopia, Italy, Kuwait, Libya, Saudi Arabia, Slovenia, Turkey, Ukraine, and USA during 2012–2013, were carried out to detect the levels of essential and toxic metal elements (arsenic, cadmium, copper, iron, mercury, lead, selenium and zinc) using Solar M Atomic Absorption Spectrophotometer. Arsenic, mercury and selenium were determined by hydride generation technique.

Improvement of a sample preparation procedure for multi-elemental determination in Brazil nuts by ICP-OES

Various sample preparation procedures, such as common wet digestions and alternatives based on solubilisation in aqua regia or tetramethyl ammonium hydroxide, were compared for the determination of the total Ba, Ca, Cr, Cd, Cu, Fe, Mg, Mn, Ni, P, Pb, Se, Sr and Zn contents in Brazil nuts using inductively coupled plasma optical emission spectrometry (ICP-OES). For measurement of Se, a hydride generation technique was used. The performance of these procedures was measured in terms of precision, accuracy and limits of detection of the elements. It was found that solubilisation in aqua regia gave the best results, i.e. limits of detection from 0.60 to 41.9 ng ml−1, precision of 1.0–3.9% and accuracy better than 5%. External calibration with simple standard solutions could be applied for the analysis. The proposed procedure is simple, reduces sample handling, and minimises the time and reagent consumption. Thus, this can be a vital alternative to traditional sample treatment approaches based on the total digestion with concentrated reagents. A phenomenon resulting from levels of Ba, Se and Sr in Brazil nuts was also discussed.

Applicability of ICP-OES, UV-VIS, and FT-IR Methods for the Analysis of Coffee Products

Spectroscopic methods were applied to study and compare the nutrient composition of ground, instant, and chicory coffee products. The total concentrations of 17 elements, including major (Ca, Mg, P) and trace (As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, Sr, Ti, Zn) elements were determined in solid samples and infusions from ground coffee by means of inductively coupled plasma atomic optical spectrometry (ICP-OES). For measurement of As and Se levels, hydride generation technique (HG-ICP-OES) was used. The accuracy of the element measurements was verified by the analysis of certified reference materials (tea leaves (INCT-TL-1), apple leaves (1515), and TORT-2). Caffeine was determined by UV spectrometry. Infrared spectroscopy was applied to investigate organic matter of the coffees. Soluble oxalate was determined by a redox titration. Additionally, measurements of some physico-chemical parameters such as moisture, ash, pH, and starch (coffee adulteration) were performed. Differences in the composition of analyzed ground and instant coffees based on the contents of caffeine, oxalate, and minerals such as Cu, Mg, P, and Zn were found. FT-IR spectroscopy was a suitable tool to characterize the presence of caffeine and oxalate.