A procedure for the determination of trace metals in rice varieties using microwave induced plasma atomic emission spectrometry

Microwave-sustained inductively coupled atmospheric-pressure plasma (MICAP) for the elemental analysis of complex matrix samples

Microwave induced plasma optical emission spectrometry (MIP-OES) has gained widespread attention in the last few years for trace elemental analysis. Among the new generation of MIPs it is worth to mention the microwave-sustained inductively coupled atmospheric-pressure plasma (MICAP) for which previous works have shown similar detection capabilities to those afforded by ICP-OES. Nevertheless, this instrument has not been applied yet to complex matrix sample analysis. Therefore, the goal of this work is to evaluate MICAP-OES performance (e.g., analytical figures of merit, matrix effects, etc.) for elemental analysis of samples of different nature (e.g., environmental, food and polymers). To this end, both spectral and non-spectral interferences were investigated for 19 elements (Ag, Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, Ga, In, Mg, Mn, Ni, Pb, Sr, Tl, Zn) in the presence of inorganic acid, organic and saline solutions and compared to a 5 % w w-1 HNO3 solution. Unlike previous MIPs, experimental data showed that the optimum nebulizer gas flow rate for a given emission wavelength was mostly independent of matrix characteristics. Regarding matrix effects, this device was highly robust operating both inorganic acid and organic matrices. Interestingly, when operating saline matrices, changes on emission signal by easily ionizable elements were less significant than those early reported by alternative MIP cavities. Moreover, due to MICAP spectrometer design employed allows real-time simultaneous analysis, Rh, Pd, Sc and Y were suitable internal standards to minimize non-spectral interferences. Finally, MICAP-OES can be successfully applied to the elemental analysis of different complex matrix samples (i.e., CRM-DW1 Drinking water; BCR-146 Sewage sludge industrial; BCR-185 Bovine liver; BCR-278R Mussel tissue; NIST-1549 Non-fat milk powder; ERM-EC681k Polyethylene (high level) and BCR-483 Sewage sludge amended soil).

Determinations of Minerals Composition of Rices in Java Island, Indonesia

Rice (Oryza sativa L.) is one of the staple foods widely consumed by Indonesian people. They usually have rice as the biggest portion on their diet, therefore rice becomes the main source of nutrients of Indonesian people mainly for those whom live in Java Islands. Although rice is known to contain various minerals, but the minerals level are varied based on differences in geographic region associated with soil quality. Hence, quantity and quality of minerals content of rice from different regions of the world are particularly important to be characterized. The present aim of the study was to assess the composition of mineral of rice from different geographical regions in Java Islands, Indonesia using nuclear analytical techniques i.e. Neutron Activation Analysis method... Quality control of data analysis was assessed using SRM NIST Rice Flour 1568a and gave good results with accuracy (% bias) ≤5% and precision (%CV) less than 10%. The essential elements contents such as Fe, Zn, and Se were quantified and found in the range of 2.8-60.9, 2.48-28.8, and 0.01-2.17 mg/kg respectively, while for the toxic elements, Cr and Co in rice are also quantified and found in the range of 0.03-1.24 and 0.003-0.59 mg/kg, respectivelyThe elemental concentrations in rices from Java Island followed the order Zn>Fe>Se>Cr>Co. It also found that rices from East Java Province have higher concentrations of Fe and Se, while the highest mean of Zn concentration was found in the rices from Jakarta province. The daily intake of those elements in rices give significant contribution to their RDA values. These results of mineral contents in rice hopefully can be used as one of references for estimating daily nutritional intake status of especially Javanese people.

Effect of Topography on Maize Grains Elemental Profile: A Chemometric Approach

Background:

The elemental composition of maize grains depends on the soil, land and environment characteristics where the crop grows. These effects are important to evaluate the availability of nutrients with complex dynamics, such as the concentration of macro and micronutrients in soils, which can vary according to different topographies. There is available scarce information about the influence of topographic characteristics (upland and lowland) where culture is developed with the mineral composition of crop products, in the present case, maize seeds. On the other hand, the study of the topographic effect on crops using multivariate analysis tools has not been reported.

Objective:

This paper assesses the effect of topographic conditions on plants, analyzing the mineral profiles in maize seeds obtained in two land conditions: uplands and lowlands.

Materials and Methods:

The mineral profile was studied by microwave plasma atomic emission spectrometry. Samples were collected from lowlands and uplands of cultivable lands of the north-east of La Pampa province, Argentina.

Results:

Differentiation of maize seeds collected from both topographical areas was achieved by principal components analysis (PCA), cluster analysis (CA) and linear discriminant analysis (LDA). PCA model based on mineral profile allowed to differentiate seeds from upland and lowlands by the influence of Cr and Mg variables. A significant accumulation of Cr and Mg in seeds from lowlands was observed. Cluster analysis confirmed such grouping but also, linear discriminant analysis achieved a correct classification of both the crops, showing the effect of topography on elemental profile.

Conclusions:

Multi-elemental analysis combined with chemometric tools proved useful to assess the effect of topographic characteristics on crops.

Rapid determination of cadmium in rice by portable dielectric barrier discharge-atomic emission spectrometer

In this work, a home-made portable dielectric barrier discharge-atomic emission spectrometer (DBD-AES) was explored to the determination of heavy metal in foodstuffs. A rapid and simple method was developed for Cd determination in rice based on this instrument. Rice was pretreated with diluted acid dissolution without complex operations and apparatus. The detection time by DBD-AES is about 3 min and the total analysis time for rice sample is within 11 min. The effects of some key experiment parameters were investigated. The limit of detection was 11.9 μg kg^-1 for Cd in rice, much lower than the maximum allowable level established by EC (200 μg kg^-1). The practical performance of this method was demonstrated by analyzing real and CRM rice samples. With the portability of DBD-AES, the method is suitable for rapid and in-field analysis of Cd in rice. It will be a useful tool for the routine analysis of rice.