Application of modified cloud point extraction method for the chromium speciation in artificial saliva extracts of different snuff products

Cr speciation analysis based on electrokinetic sample pretreatment with a paper based analytical device

This work presents a new method of Cr speciation analysis based on micro sample pretreatment with a paper-based analytical device (PAD). By using electrokinetic separation and stacking on the PAD, Cr (VI) and Cr (III) can be separated and the recovered to achieve speciation analysis without have to be subjected to subtraction treatment. The separation and recovery properties of Cr (VI) and Cr (III) were characterized and optimized by UV-Vis spectrophotometry, with which the LOQ of 19.0 μg L^-1 and 28.7 μg L^-1, and the recoveries of 88-108% and 90-110%, were obtained for Cr (VI) and Cr (III), respectively. In addition, direct analysis of Cr (VI)/Cr (III) from an electroplating wastewater sample was also demonstrated with this method combined with atomic spectroscopy (GF-AAS and ICP-OES). This sample pretreatment method is fast, cheap and easy to be used. Combined with the high sensitivity and elemental selectivity of atomic spectroscopy and mass spectrometry, this PAD sample pretreatment method could be a compensation to their lack in speciation discrimination, and may play an important role in the speciation analysis of Cr.

A novel colorimetric probe with positive correlation between toxicity and the reaction for the assessment of chromium ions

Different valence states of chromium ions possess huge differences in toxicity. Hence, it is an innovative idea to design a reasonable probe to detect Cr according to the toxicity characteristics of different valence states. We report a novel, rapid, simple and accurate probe for the detection of Cr³⁺ and Cr⁶⁺ ions. As a probe, gold nanoparticles (Au NPs) are successfully modified using tartaric acid (TA) and 2-[4-(2-hydroxyethyl)-1-piperazinyl] ethanesulfonic acid (HEPES) via a two-step modification; the probe shows an increase in the sensitivity towards Cr⁶⁺ and decreases towards Cr³⁺, which is consistent with their toxicity characteristics, benefiting the assessment of total Cr toxicity. The proposed probe achieves considerable two-channel (ultraviolet absorption spectrum and naked eye vision) detection of Cr³⁺ and Cr⁶⁺ providing wide linearity regions and low detection limits. Meanwhile, the results of the interference experiments and analysis of the real samples showed high selectivity and accuracy of the proposed method. With popularization, this method possesses great potential in environmental monitoring and control.

Ion-exchange HPLC-ICP-MS: A new window to chromium speciation in biological tissues

The presented work proposes a novel analytical ICP-MS-based approach for the accurate and precise chromium speciation in biological tissues. The determination of total Cr(VI) and soluble Cr(III) species was carried out by alkaline EDTA extraction followed by their separation using ion-exchange high-performance liquid chromatography inductively coupled plasma mass spectrometry (IE-HPLC-ICP-MS). The developed method was validated according to the procedure given in the United States Food and Drug Administration guideline on the validation of bioanalytical methods. Validation parameters included limit of detection (≤ 0.03 μg g^-1), limit of quantification (≤ 0.08 μg g^-1), linearity (r ≥ 0.9998), intra-day and inter-day accuracy (86-110%) and precision (≤ 10%), extraction recovery (89-110%), carry-over effect and sensitivity. In addition, special attention was paid to the study of chromium species interconversion and the elimination of spectral interferences. Moreover, the validated ICP-MS method employing microwave acid digestion was used to determine the total Cr content in collected fractions. Finally, the whole ICP-MS-based methodology was applied to the analyses of two certified reference materials of hepatopancreas tissue. Obtained results indicated that the majority of chromium in biological tissues is bound to the solid residue, Cr(VI) was determined in none of the samples investigated. This is the first study focusing on soluble Cr(III), total Cr(VI), and total bound Cr species in biological tissues. It is characterized by efficient sample preparation and fast simultaneous analysis of Cr species with parallel total Cr analysis serving for chromium balance evaluation.

Assessment of carcinogenic and toxic substances in 'Insunko' herb

There has emerged a herb in Zambia called 'insunko' which has unknown chemical composition. The use of 'insunko' herb with unknown chemical composition has brought mixed feelings among many Zambians. This study, therefore, aimed to assess the toxic and carcinogenic substances in'insunko' herb. 'Insunko' herb was purchased from Chipata, Lusaka, Mpika, Mwense, Kitwe, and Solwezi. 5 samples were collected from each of these districts and were thoroughly mixed to give 6 consolidated samples (n = 6). Nicotine and, nitrosamines were analysed using UV spectrometer lambda 35 Perkin Elmer while trace metals were analysed using ICP-MS Inductively Coupled Plasma Mass Spectroscopy (Agilent Technologies, Santa Clara, CA, USA). Nicotine, nitrosamines, and trace metals were detected in high concentrations. The concentrations ranged from 3.87 to 9.83 mg/kg for nitrosamines and 10.94-34.01 mg/kg for nicotine. Hazard Indexes for arsenic, cadmium, chromium, manganese, and copper were greater than one (HI > 1). 'Insunko' herb is a potentially toxic and carcinogenic substance because it contains toxic and carcinogenic constituents in high concentrations. These toxic and carcinogenic constituents have been confirmed to cause gastrointestinal disorders, cancers, degenerative, cardiovascular, hematopoietic, neurologic and cognitive problems as well as male infertility.