Elements In Plant Samples Research Articles

Recent Advances in the Determination of Major and Trace Elements in Plants Using Inductively Coupled Plasma Optical Emission Spectrometry.

Interest in measuring major and trace elements in plants has increased in recent years because of growing concerns about the elements' contribution to daily intakes or the health risks posed by ingesting vegetables contaminated by potentially toxic elements. The recent advances in using inductively coupled plasma atomic emission spectrometry (ICP-OES) to measure major and trace elements in plant samples are reviewed in the present work. The sample preparation before instrumental determination and the main advantages and limitations of ICP-OES are described. New trends in element extraction in liquid solutions using fewer toxic solvents and microextractions are observed in recently published literature. Even though ICP-OES is a well-established and routine technique, recent innovations to increase its performance have been found. Validated methods are needed to ensure the obtaining of reliable results. Much research has focused on assessing principal figures of merit, such as limits of detection, quantification, selectivity, working ranges, precision in terms of repeatability and reproducibility, and accuracy through spiked samples or certified reference materials analysis. According to the published literature, the ICP-OES technique, 50 years after the release of the first commercially available equipment, remains a powerful and highly recommended tool for element determination on a wide range of concentrations.

After-effects of a closed copper mine: detailed analysis of environmental impacts in soil and plant samples

In several countries around the world, abandoned mining sites are blighted by pollution from metal and metalloids. Generated by mining processes, toxic pollutants have lasting effects on the ecosystem. The study examined the environmental impact of waste from a copper mine that was operated by the Caucasus Copper Limited Company between 1905 and 1928, revised and commissioned by Etibank in 1936, and ceased operations 75 years ago. Soil and plant samples (needles of Scotch pine, Pinus sylvestris L.) were collected from five specific regions around the mine and the levels of potentially toxic elements (PTEs) were determined, including As, Zn, Pb, Cd, Ni, Mn, Cr, Cu, Al, and Fe. The data obtained were used to calculate the enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF), ecological risk index (ERI), human health risk index (BCF), and plant enrichment factor (EFPlant). In soil samples, the average EF values of certain elements such as As (453), Cu (59.9), Pb (30.7), Zn (5.26) were detected at high levels. However, average Igeo values indicate high pollution levels for As (8.25), Cd (6.72), Cu (4.94), Pb (4.33) and Zn (2.42), indicating the existence of serious ecological risks in the affected areas. Additionally, the average CF values indicate serious pollution levels from heavy metals such as As (1605), Cd (584), Pb (99.4), Cu (81.9), and Zn (14.6), highlighting the extensive pollution situation resulting from mining activities. Meanwhile, average ERI values indicate that Cd, As, Cu, and Pb pose serious ecological risks in the study areas.These PTEs were found in high concentrations in the waste tail and dump. Furthermore, the analysis determined that there was enrichment for Mn, Cd, Al, Cu, Pb, and Fe elements in plant samples. These PTEs have the potential to spread more widely depending on seasonal conditions and local topography. This situation demonstrates the need to measure metal and metalloids concentrations at certain times, taking into account the potential for environmental pollution of surface runoff water and underground resources in areas with high drainage potential from acid mines, such as at the Kuvarshan mine tailings site.

Elemental Analysis of Five Medicinal Plants Species Growing in North Ossetia Using Neutron Activation Analysis

One important category of traditional remedies is medicinal plants, which are widely consumed by the population and often subjected to contamination. For the first time, the elemental composition of five wild medicinal plants traditionally consumed in the Republic North Ossetia—brook-mint (Mentha longifolia), oregano (Origanum vulgare), St. John’s wort (Hypеricum perforаtum), thyme (Thymus daghestanicus), and fireweed (Chamaenerion angustifolium)—and corresponding soil samples was determined. This investigation aimed to assess the degree of toxic element accumulation in plants and the possible toxic effect of the analyzed plants on human health. The analysis encompassed the quantification of 36 major and minor elements in soil samples, alongside the detection of 23 elements in plant samples using instrumental neutron activation analysis. According to contamination and enrichment factors, which were calculated in order to assess the level of soil pollution, elements such as As, Sb, Zn, and U in soil may originate from both geogenic and anthropogenic sources. In all plant samples, the most abundant major elements were K and Ca and their content ranged from 9870 to 49,500 mg·kg−1 and 5400 to 20,000 mg·kg−1, respectively, while among the microelements, Fe (54–2080 mg·kg−1) and Mn (27.8–190 mg·kg−1) can be highlighted as the most abundant. The transfer factor was calculated to estimate metal uptake from soil in plants. The highest values of the transfer factor were obtained for Mo, K, Ca, and Zn. The daily intake of metals and the health risk index were calculated to assess the safety of the collected plants. The health risk index was below the threshold for all plants suggesting a probable non-carcinogenic effect. Principal component analysis and linear discriminant analysis were used as classification techniques. The principal component analysis allowed us to define the main groups of elements and associate them with their sources of origin, while discriminant analysis enabled us to discriminate plant samples by species.

Determination of major and trace elements in plant samples by inductively coupled plasma optical emission spectrometry with deep eutectic solvent extraction based on choline chloride and carboxylic acids.

A rapid, precise, and environmentally friendly approach utilizing an ultrasound assisted deep eutectic solvent-based extraction method was developed for the extraction of Ca, Fe, K, Mg, Mn, Na, P, S and Zn from plant samples. The investigation was conducted on deep eutectic solvents that are based on choline chloride and carboxylic acids. The determination of target analytes in the extracts was carried out using inductively coupled plasma-optical emission spectrometry (ICP-OES). The DESs based on malic acid were found to exhibit the highest extraction recovery values (95-106%). The parameters affecting the extraction of target analytes were optimized using standard reference materials. The target analytes can be effectively extracted from plant samples using 0.5 g of DESs and ultrasonication for 40 minutes. The determination results of the reference samples indicated that the relative error (RE) was below 15.1%, and the relative standard deviation (RSD) was less than 6.3%, demonstrating excellent accuracy and precision. The proposed method was employed to quantify target analytes in actual plant samples. The accuracy of this method was not significantly different from that of the microwave digestion method. The proposed method has been demonstrated to be a valid approach for the determination of target elements in actual plant samples.

Biogeochemical prospecting for gold at the Yellowknife City Gold Project, Northwest Territories, Canada: Part 1 - Species optimization

The Yellowknife City Gold Project (YCGP), located close to the city of Yellowknife, Northwest Territories, Canada, is exploring and drilling the extension of the Au-bearing shear zones that host the Giant and Con Mines. A biogeochemical survey was conducted over the Crestaurum and Barney deposits, which are hosted within two well-known high Au grade shear zones at the YCGP. A total of 625 samples were collected from the alder (Alnus incana) (n = 76), Labrador tea (Ledum groenlandicum) (n = 40), black spruce (Picea mariana) (n = 189), and juniper (Juniperus) (n = 320), and analyzed using ICP-MS. Robust statistical analyses were applied to biogeochemical data to (1) identify the biogeochemical response in plant samples with respect to the underlying mineralogy, (2) detect the most preferred plant species in the study area, and (3) identify Au pathfinder elements and subsequently zones of Au enrichment. Principal component analysis (PCA) and K-means clustering analysis were employed to achieve these objectives. The preliminary statistical analysis showed that plant samples can successfully accumulate anomalous Au values up to 147 ppb. Also, it showed that black spruce and Labrador tea can accumulate higher concentrations of Au than alder and juniper. According to the PCA, mineralization/geological (PC1) and physiological (PC2) factors control the distribution of elements in plant samples. According to K-means clustering, plant samples were classified into three clusters based on the vegetation type and their affinity to accumulate suites of elements. Black spruce samples were identified as the optimum sample media for biogeochemical exploration at the YCGP as they were clustered in proximity to the mineralization/geological factor (PC1) responsible for loading vectors of Au, Ag, As, Se, Bi, Pb, Cu, Co, Fe, Zn, Cd, Tl, and Cr. Au is strongly correlated with its pathfinder elements (Ag, As, Se, Bi, Tl and Sb), specifically in the south of the Crestaurum Shear. The presented results in this study demonstrate that zones of Au enrichment can be detected using biogeochemical and robust statistical methods.

Using Portable X-ray Fluorescence Spectroscopy for Inexpensive and Quick Determination of Micronutrients in Barley Shoots

ABSTRACT Determination of elemental concentrations in plant tissue samples is critically important for analyzing their nutritional content. Micro-elemental analysis mostly relies on inductively coupled plasma (ICP) spectrometry techniques, which are expensive, time-consuming, laborious, and complicated. Portable X-ray fluorescence (pXRF) spectroscopy is widely applied in earth sciences but is rarely practiced to quantify elements in plant samples. In this pilot study, the reliability of pXRF results was compared with that of ICP-mass spectrometer (MS) to determine concentrations of four micronutrients zinc (Zn), iron (Fe), copper (Cu), and cadmium (Cd) in barley (Hordeum vulgare L.) shoot samples. Ground barley samples were scanned with the pXRF instrument. The concentrations of Zn recorded using this method correlated well with the ICP-MS results (R 2 = 0.80), while Fe and Cu concentrations showed moderate correlations (R 2 = 0.57 and 0.42, respectively). However, no significant correlation was found between ICP-MS- and pXRF-derived concentrations for Cd (p > .05). This work demonstrated the potential of pXRF as a reliable and cost-effective alternative to ICP methods for determining Zn in plant samples as it allows the analysis of a greater number of samples in a short period at considerably less expense.

Comparison of non-destructive techniques and conventionally used spectrometric techniques for determination of elements in plant samples (coniferous leaves)

Conventionally used spectrometric techniques of inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma optical emission spectrometry (ICP-MS) usually involve time-consuming sample preparation procedure of a sample dissolution which requires the usage of aggressive and toxic chemicals. The need for suitable and sustainable analytical methods for direct multi-elemental analysis of plant samples has been increased in recent years. Spectrometric techniques for direct sample analysis, instrumental neutron activation analysis (INAA) and X-ray fluorescence (XRF) have been applied in environmental studies and various fields of screening tests. Nevertheless, these techniques are not commonly used for plant sample analysis and their performances need to be evaluated. This research aimed to assess how reliable non-destructive techniques are in the determination of elements in plants compared to conventionally used spectrometric techniques. A total of 49 plant samples of four conifer species (Pinus nigra, Abies alba, Taxus baccata and Larix decidua) were measured using two conventionally applied (ICP-MS, ICP-OES) and two non-destructive techniques (wavelength dispersive XRF (WD-XRF), INAA). The comparison was performed by investigation of relative ratios of concentrations and by correlation analysis. Moreover, precision of the techniques was examined and compared. The quality control included analysis of NIST pine needles certified reference material (1575a) using all examined techniques. Our results suggest that additional analytical and quality control steps are necessary for reaching the highest accuracy of multi-elemental analysis.

Determination of Rare Earth Elements in Plant Samples by ICP-MS with Microwave Digestion

Method of microwave digestion using HNO3, HCl and HF in MARS‑5 system followed by ICP-MS analysis is proposed for determination of rare earth elements (REE) in plant materials. Limits of detection are 0.0001–0.001 ppm and allow for determination of all REE in certified reference materials Tr‑1, LB‑1 and EK‑1 and new reference material NSP‑1, relative standard deviations are lower than 13 %.Influence of HF addition during microwave digestion in UltraWAVE system on the ICP-MS analysis of REE in plant materials depending on silica content is studied. Necessity of HF addition during microwave digestion for better REE recoveries is shown for plant materials with Si contents exceeding 0.1 %

Artificial cellulose standards as calibration standards for wavelength-dispersive X-ray fluorescence analysis of elements in plant samples

This research explores the possibilities and limitations of WD-XRF, applied as a method for quantification of 20 elements in plant material, using spiked cellulose standards for calibration. Three different analytical methods were investigated: 1) standards created from pure spiked cellulose; 2) spiked cellulose mixed with 20% of binder and 3) spiked cellulose applied as a thin layer on an inert carrier. Sensitivity, linearity, limit of detection, limit of quantification, repeatability, intralaboratory reproducibility, and accuracy were determined and compared. The accuracy of the investigated methods was tested by analysis of standard reference materials and comparison with other routinely used analytical techniques (ICP-OES and ICP-MS). The comparison included real plant samples which were collected from the environment characterized by different pollution levels. The accuracy of the semiquantitative standardless method was also considered and compared with other investigated methods. Tested methods can be very precise, with good intralaboratory reproducibility over wide linear range.

Determination of Heavy Metals in the Plant Sample Pretreatment Methods

In this paper, dry ashing method, mixed acid nitration (H2SO4-H2O2), three acid digestion (HNO3-H2SO4-HClO4) and aqua-regia-HClO4 these four test solution preparation method on the decomposition of plant standards GBW07603 processing, use atomic absorption spectrophotometry Zn, Cu, Pb, Fe, Cd, Cr six kinds of metal elements, and the measured values compared with the standard value. The results showed that after dry ashing recoveries higher than Zn recovery after acid digestion; Cu determination should not use dry ashing; Pb determination should not be used mixed acid nitration (H2SO4-H2O2) or tri-acid digestion method (HNO3-H2SO4-HClO4);dry ashing treatment after acid digestion Cr yield higher Cr recoveries. Comprehensive analysis of the low carbon content of the metal elements in plant samples (Zn, Cu, Pb, Fe, Cd, Cr) of the measurement, can be aqua-regia-HClO4 pretreatment method, and for comparing the carbon content high plant samples should be used as a dry ashing pretreatment method. That is, different pretreatment methods for the determination of different analyte have a certain impact.

Decomposition rate of peat-forming plants at the initial stages of destruction in peat deposits of the oligotrophic bogs “Bakcharskoe” and “Timiryasevskoe”

The research presents quantitative estimates of the decomposition rate of plant residues at the initial stages of the decay of four plant species (Eriophorum vaginatum, Carex rostrata, Sphagnum fuscum, Sphagnum angustifolium) in peat deposits of the oligotrophic bogs in the southern taiga subzone of Western Siberia. We also studied the change in the content of total carbon, nitrogen and ash elements in plant residues and the activity of microflora at the initial stages of decomposition. The studies were conducted in the bogs characterized by various hydrothermal conditions. At the initial stage of the decay of peat-forming plants the maximum losses of mass occur in the first month of the experiment and reach 36-52% of the total loss of organic matter during the growing season. Sphagnum fuscum is the most resistant to decomposition. The most intense decomposition of Sphagnum fuscum at the initial stages of decomposition is characteristic for warmer and less humid conditions of the Timiryazevskoe bog. It was revealed that mass losses of organic matter correlate well with total carbon losses. The most intensive decreasing of the total carbon content as well as mass loss of organic matter are observed after the first month of the experiment. The maximal decline of carbon in plant residues was received for Eriophorum vaginatum. During the decomposition of plant residues, the nitrogen content was decreasing, and the most intense nitrogen losses were characteristic for Sphagnum mosses. Nitrogen loss in peat-forming plants during the first month of decomposition varies depending on the locality conditions, but it becomes equal during the later decomposition stages. At the first stages of decomposition of plant residues, both the accumulation and the loss of ash elements were observed in the samples. Both the Bakcharskoe and Timiryazevskoe bogs were characterized by the accumulation of ash elements in plant samples of Eriophorum vaginatum. Dynamics of mass loss and removal of elements are directly related to the activity of microorganisms. The maximum number of microorganisms was found in July and September. Peat and plant samples located in the peat deposit of the Timiryazevskoe bog are more saturated with microorganisms of the nitrogen cycle, and samples from the Bakcharskoe bog are richer in carbon cycle microorganisms. Microorganisms of the lignocellulosic complex were less active as compared with other groups of microorganisms. The number of microorganisms assimilating the mineral forms of nitrogen are on average 1.5 times less than the number of microorganisms assimilating the organic forms. The positive correlation between the nitrogen content and the number of fungi was found. In addition, correlation between the numbers of denitrifiers and oligotrophs was found. It is explained by trophic relationshipsbetween these groups of microorganisms.

Phenolic compounds, biological activities and trace elements of Capparis ovata var. canescens

Introduction: Capparis species (Capparaceae), also called caper, grow naturally in various regions of the world. Caper is a plant with medicinal and aromatic properties. Flower buds, root bark, and fruits of the plant are used in folk medicine due to their analgesic, wound healing, cell regeneration, tonic, and diuretic effects. Objective: The aim of this research was to evaluate in vitro (anti-urease, antioxidant, anticholinesterase) and in vivo (anti-inflammatory) biological activities of caper (C. ovata var. canescens). In addition, we aimed to identify its major phenolic compounds using high performance liquid chromatography with a photodiode array detector (HPLC-DAD) and confirmate them using quadrupole time-of-flight liquid chromatography with tandem mass spectrometry (Q-TOF-LC/MS). Also, we quantified the concentrations of several trace and major elements in plant samples using inductively coupled plasma-mass spectrometry (ICP-MS). Methods: The antioxidant, anti-urease and anticholinesterase activities of different plant extracts were evaluated using DPPH, FRAP, ABTS/TEAC, Indophenol and Ellman tests. The identification of phenolic compounds and trace element contents was performed using HPLC and Q-TOF-LC/MS and ICP-MS. Results: Soxhlet methanol extract exhibited the strongest anti-urease, antioxidant (ABTS/TEAC) and anticholinesterase activity. Soxhlet and maceration methanol extracts demonstrated significant anti-inflammatory effect in the altered edema size after the second hour of carrageenan injection. The active phenolic compounds in Soxhlet methanol extract were identified as rutin, quercetin-hexoside-hexoside, quercetin-3-O-hexoside and kaempferol-3-O-rutinoside. In addition, the average concentrations of vanadium, chromium, manganese, cobalt, copper, nickel, arsenic, selenium, zinc and lead were within the permissible limits defined by WHO for medicinal plants. However, it was found that the concentrations of cadmium and iron were higher than the maximum permissible limits. Conclusion: Our results suggest that although caper has a strong biological activity, it should be consumed carefully due to the excess amount of cadmium and iron elements it contains.

Determination of key elements in plant samples by inductively coupled plasma optical emission spectrometry with electrothermal vaporization

Inductively coupled plasma optical emission spectrometry combined with electrothermal vaporization (ETV) was used for determination of Ba, Ca, Co, Cu, Fe, K, Mg, Mn, P, Sr, Zn, S, and Se in plant materials. Optimized temperature program comprised a pyrolysis phase (duration 60 s and max. temperature 600 °C) and analytical phase (duration 70 s and temperature gradually increasing to 2500 °C); dichlorodifluoromethane (known as Freon R12) was used as a chemical modifier. High plasma power for robust plasma conditions was used. Calibrations based on certified reference materials of plant and animal origin and aqueous calibration solutions were linear for most of the used spectral lines and were stable for several months. Limits of detection were in the range from 7 to 1100 mg/kg for plant main elements and from 0.074 to 4.3 mg/kg for plant minor and trace elements. The precision of results was below 6%, and recovery was 83–116%. Results of inductively coupled plasma optical emission spectrometry with ETV were in good agreement with results of inductively coupled plasma optical emission spectrometry with pneumatic nebulization sample introducing system and inductively coupled plasma mass spectrometry obtained in the same laboratory, and differences between results were generally lower than 10%. Then, the amounts of selected elements, which are important indicators of plant health and nutritional value, were determined. The agreement of our results with results obtained in another laboratory was acceptable in case of S, K, Ca, and Se (differences lower than 10%). In case of determination of Mg, P, Cu, Mn, and Zn, the differences ranged from 20 to 25%.

The elemental composition of halophytes correlates with key morphological adaptations and taxonomic groups

Halophytes are crucial in the light of increasing soil salinization, yet our understanding of their chemical composition and its relationship to key morphological traits such as succulence or salt excretion is limited. This study targets this issue by exploring the relationship between the elemental composition of 108 plant species from saline environments in Iran and their eco-morphological traits and taxonomy. Leaves and/or photosynthetic shoots of individual species and soils were sampled and analyzed for 20 elements in plant samples and 5 major elements plus % gypsum content, pH, and EC in soil samples. Eu-halophytes and leaf- and stem-succulent and salt-recreting plants showed high concentrations of Na, S, and Mg and low concentrations of Ca and K. In contrast, pseudo-halophytes, facultative-halophytes and eury-hygro-halophytes, which often lack succulent shoots, showed low Na, S, and Mg and high Ca and K concentrations in their leaves. Clear patterns were identified among taxonomic families, with Chenopodiaceae and Plumbaginaceae having high Na and Mg and low Ca and K concentrations, Caryophyllaceae having high K, Poaceae having low Na, and Asteraceae, Boraginaceae, and Brassicaceae showing high foliar Ca concentrations. We conclude that the elemental composition of halophytes and pseudo-halophytes is related to salt-tolerance categories, eco-morphological types and respective taxonomic groups.

Comparison of Open Digestion Methods for the Determination of Rare Earth Elements in Plant Samples by ICP-MS

ABSTRACTAn analytical procedure for the reliable determination of rare earth elements (REEs) in plant samples by inductively coupled plasma-mass spectrometry (ICP-MS) was developed. The influence of the main matrix elements was investigated first. It was established that moderate amounts (0.1–1.0%) of dissolved solids decreased the REEs signals significantly. Internal standardization with indium proved to be useful for obtaining correct results. Various digestion procedures were next applied to converting various solid plant samples to aqueous solution, namely dry-ashing, dry-ashing including a hydrofluoric acid (HF) step, and wet digestion using hydrogen peroxide (H2O2) and nitric acid (HNO3). Obtained results showed that the simple dry-ashing procedure was sufficient for plants. A certified reference material (BCR-670, aquatic plant) was used to validate the accuracy of the method. Relative standard deviations varied from 1% (holmium, gadolinium) to 4% (europium). Detection limits between 13 (lanthanum) and 0.02 ng L−1 (lutetium) were achieved.

Determination of concentrations of chromium and other elements in soil and plant samples from leather tanning area by Instrumental Neutron Activation Analysis

Chromium, one of the toxic elements, along with other elements has been determined in samples of soil and plant (leaves and seeds) from Jajmau Area, Kanpur district, India, which is irrigated with effluent waste water from leather tanning industries. Soil and plant samples were collected from these areas and analyzed by Instrumental Neutron Activation Analysis (INAA) using high flux reactor neutrons and high resolution gamma-ray spectrometry. Concentrations of fifteen elements in soil and five elements in plant samples were determined by relative method. Chromium concentrations were found to be in range of 45–3,900 mg kg−1in soil samples and 14–83 mg kg−1 in plant samples. This study showed that Cr is present in significant amounts, in the soil as well as in the plant samples, near to the leather tanning area. As a part of quality control work, IAEA reference material (RM) SL-3 and NIST standard reference material (SRM) 1645 were analyzed and the quality of the results has been evaluated by calculating % deviations from recommended/literature/certified values.

Optimization of sample preparation and ICP-MS analysis for determination of 60 elements for characterization of the plant ionome

An ICP-MS method for determination of 60 elements in plant samples is proposed based on optimization of digestion, recommending use of HF besides HNO3 and H2O2 and calibration procedures, using CRMs for construction of calibration curves. Adequate choice of analytical isotopes and various measurement conditions (cold plasma for the determination of Al, Ba, Ca, Fe, K, Mg, Mn, Na, Si and Sr and DRC mode for determination of Ag, As, Ni, Pd, Pt, Se and V) as well as introduction of appropriate corrections lead to determination of as large number of elements with quadropole ICP-MS as with the more expensive SF-ICP-MS. Two measurements are performed: cold plasma and standard/DRC mode. The analytical characteristics of the method are demonstrated by analysis of five CRMs and the agreement of the experimental results with the certified/information/literature values is very good. Detection limits are low enough to permit the determination of all elements but platinum metals at background level. The applicability of the method is demonstrated by analysis of Taraxacum officinale (dandelion) samples collected from regions with different anthropogenic influence. The results indicate high degree of pollution round the Pb-Zn smelter with As, Cd, Cu, Ni, Pb and Zn and increased concentrations of B, Be, Bi, Hg, In, Mn, Sb, Se, Sn, Ti, Tl, V and Zr. The dandelion sample, collected along a highway has increased concentrations of traffic released elements: Pt, Pd, Rh, Ce, La, Pb as well as Cu, Zn, Ba and Rb.

Determination of Major and Trace Elements in Plant Samples by Inductively Coupled Plasma–Mass Spectrometry

The determination of several trace elements [arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), molybdenum (Mo), nickel (Ni), and lead (Pb)] in plant samples using inductively coupled plasma–mass spectrometry (ICP‐MS) was evaluated. It was established experimentally that moderate amounts (0.2–2%) of dissolved solids decreased the analyte signals significantly. Internal standardization with Rh was efficiently used to compensate for these matrix effects. The accuracy of the method was verified using reference materials digested according to two different procedures: dry ashing and microwave digestion. No significant differences were observed between measured concentrations and certified values. The investigation was next extended for the determination of major elements [aluminum (Al), boron (B), calcium (Ca), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), phosphorus (P), and zinc (Zn)] on the same reference materials. The ICP‐MS values agree well with the values supplied. However, it appeared that Sc was the most useful internal standard for major elements.

Application of laser-induced breakdown spectroscopy in analyzing microelements in three kinds of fruit samples

It is a relatively new task to apply the laser-induced breakdown spectrosopy(LIBS) to plant samples. To apply LIBS technique in the field related to foodstuff safety, we have done primary experiments using three kinds of fruit samples prepared by vacuum freeze-dried technique using the technique of discriminated LIBS spectra. The relative contents of six trace elements Ca, Na, K, Fe, Al and Mg in the samples were analyzed. By comparison we found that in apple samples the relative content of Na is the highest and the relative content of Ca is the lowest, and the contents of K, Fe, Mn, Mg are different for different fruit samples. Experiment results showed that LIBS technique is a valid means for measuring and comparing the content of trace elements in plant samples.

Direct determination of major elements in solid plant materials by electrothermal vaporization inductively coupled plasma atomic emission spectrometry

The present work demonstrates the capability of electrothermal vaporization (ETV) to become an important tool of solid sample introduction in ICP-AES for plant sample analysis. Direct determination of Al, Ca, Fe, K, Mg, Mn, Na and Zn was investigated in powdered plant samples. Obtaining good results for major elements in plant samples was governed by some special operating conditions. The sensitivity of the method necessitated the use of ICP in radial view configuration. The behavior of elements during vaporization was studied between 500 and 2600 °C. External calibration was carried out using solid external (cellulose) spiked with aqueous standard solutions. However, performances of the analytical method were found dependent of argon flow rates. Analytical accuracy of the method was tested in three reference materials. Analytical results agreed with certified values when cellulose was used in calibration. However, K could not be determined because of excessive sensitivity. Without cellulose, it was found that Fe results were underestimated and Zn results overestimated. Relative standard deviations varied from 3 to 23%. Limits of detection varied from 1 to 80 ng g −1 from one element to the other for a typical mass sample of 2 mg.