Development of microwave assisted-UV digestion using diluted reagents for the determination of total nitrogen in cereals by ion chromatography

Pretreatment methods in ion chromatography: A review

As an advanced analytical technology, Ion Chromatography (IC) has been widely used in various fields. At present, it is faced with the challenges of sample complexity and instrument precision. It is necessary to select appropriate pretreatment methods to achieve sample preparation and protect the instruments. Therefore, this paper reviews several commonly used sample pretreatment technologies in IC, focusing on sample digestion and purification techniques. Additionally, we introduce some advanced IC technologies and automatic sample processing devices. We provide a comprehensive summary of the basic principles, primary applications and the advantages and disadvantages of each method. Pretreatment methods should be carefully selected and optimized on the specific characteristics of the sample and the ions to be measured, in order to achieve better analysis results.

Effects of Streptomyces sp. HU2014 inoculation on wheat growth and rhizosphere microbial diversity under hexavalent chromium stress

Wheat (Triticum aestivum L.) is a major foodstuff for over 40% of the world's population. However, hexavalent chromium [Cr(VI)] in contaminated soil significantly affects wheat production and its ecological environment. Streptomyces sp. HU2014 was first used to investigate the effects of Cr (VI) stress on wheat growth. We analyzed the Cr(VI) concentration, physicochemical properties of wheat and soil, total Cr content, and microbial community structures during their interactions. HU2014 reduced the toxicity of Cr(VI) and promoted wheat growth by increasing total nitrogen, nitrate nitrogen, total phosphorus, and Olsen-phosphorus in Cr(VI)-contaminated soil. These four soil variables had strong positive effects on two bacterial taxa, Proteobacteria and Bacteroidota, in the HU2014 treatments. In addition, the level of the dominant Proteobacteria positively correlated with the total Cr content in the soil. Among the fungal communities, which had weaker correlations with soil variables compared with bacterial communities, Ascomycota was the most abundant. Our findings suggest that HU2014 can promote the phytoremediation of Cr(VI)-contaminated soil.

Microwave-assisted UV digestion of starch and skimmed milk powder: Environmentally friendly protocol for essential and toxic elements determination

The present work evaluated a microwave-assisted wet digestion method using diluted HNO3 with in situ UV radiation for the digestion of starch and skimmed milk powder for further metals determination by spectrometric plasma-based techniques. The sample digestion was conducted using an in situ UV lamp (electrodeless discharge lamp), and the digestion efficiency was improved by employing O2 (20 bar) and 2 mL 30 % H2O2 as auxiliary reagents. The accuracy of the proposed digestion method was evaluated by metals determination (Ca, Cd, Cu, Fe, K, Mg, Mo, Mn, Na, Pb, and Zn) in certificated reference material, which agreed with certified values (Student t-test <0,05). With the use of a UV lamp an environmentally friendly protocol was developed for starch and skimmed milk powder digestion using 0.1 mol L-1 HNO3 with auxiliary reagents (H2O2 or O2). The RCC value ranged from 0.9 to 1.2 % (starch and skimmed milk powder, respectively). The simultaneous cooling approach further improved the digestion efficiency (RCC <0,3 % for both samples), allowing to use milder digestion conditions, or even just water, being environmentally friendly, reducing the waste generation and reagents consumption, allowing food quality control through a greener approach.