A Powder X-Ray Diffraction Method for Qualitative Detection of Potassium Bromate in Bakery Ingredients and Products

A turn-off Eu-MOF@Fe2+ sensor for the selective and sensitive fluorescence detection of bromate in wheat flour

A new europium metal-organic framework (Eu-MOF) was prepared by simple hydrothermal method. The product exhibited intense red fluorescence, long fluorescence lifetime (0.454 ms) and excellent fluorescence stability. The fluorescence titration result showed that Fe³⁺ could completely quench the fluorescence of Eu-MOF, while the fluorescence quenching effect of Fe²⁺ or bromate was negligible. Considering the strong oxidizing property of bromate, a "turn off" Eu-MOF@Fe²⁺ sensor toward bromate was designed by generating Fe³⁺ due to the redox reaction. The results showed that the sensor displayed a wide linear range (0-0.2 mM), high sensitivity (LOD = 3.7 × 10^-6 mol/L), good selectivity and resistant to possible interferences in real four sample. Furthermore, the detection mechanism was investigated by PXRD, XPS and UV-Vis methods. More importantly, the Eu-MOF@Fe²⁺ sensor was further applied to detect bromate in wheat flour with satisfactory recovery (95.30%-104.38%) and accuracy (RSD < 2.85%). These results suggest that Eu-MOF@Fe²⁺ can be used as a potential sensor to detect bromate in food industry.

Geophagic Clays from Cameroon: Provenance, Metal Contamination and Health Risk Assessment

This study assessed the mineralogical and geochemical characteristics of geophagic clays sold in some markets in Cameroon to ascertain their provenance, contamination status and human health risk. To achieve this, 40 samples from 13 markets in Cameroon were purchased and analysed using X-ray diffractometry, X-ray fluorescence and laser ablation inductively coupled plasma mass spectrometry for their mineralogy and geochemistry, respectively. The geophagic clays were dominantly made up of kaolinite and quartz. Their chemistry was dominated by SiO₂, Al₂O₃ and LOI with means of 48.76 wt%, 32.12 wt% and 13.93 wt%, respectively. The major, trace and rare earth elements data showed that these geophagic clays were predominantly derived from felsic rocks. The contamination assessment indicated no enrichment of metals from anthropogenic sources, except for Zn in samples from Acacia, Madagascar and Mfoudi markets. The index of geo-accumulation indicated no contamination to moderate contamination of the clays. The non-carcinogenic index values for Fe, Co, Cr, Cu, Ni, Pb and Zn were generally less than 1, suggesting no non-carcinogenic risk exposure to children and adults consuming the geophagic clays from these metals. The carcinogenic risk index (TCR) for Ni and Cr were above 10⁻⁶, which implies that children and adults are vulnerable to minimal carcinogenic health risk. The TCR values from Ni posed the highest risk, especially to children consuming clays from some markets.