Magnetic porous carbons derived from iron-based metal-organic framework loaded with glucose for effective extraction of synthetic organic dyes in drinks.

The conversion of metal-organic frameworks (MOFs) to porous carbon has attracted extensive attention for developing multifunctional adsorbent materials. Herein, we demonstrated a facile method to prepare magnetic porous carbon via calcinating MIL-101(Fe) precursor loaded with glucose at 700 °C in an N2 atmosphere. The obtained magnetic porous carbon (MPCG) contained plenty of oxygen-containing functional groups and exhibited an enlarged specific surface area (177.7 m2/g) compared with its precursor (41.2 m2/g). In addition, MPCG can be easily separated from the matrix by a magnet. Benefitting from these advantages, the magnetic porous carbon exhibited high affinity toward four synthetic organic dyes (amaranth, ponceau 4R, sunset yellow, and lemon yellow) in an aqueous solution. Moreover, the adsorbent can be applied to quantitatively detect synthetic organic dyes in drinks coupled with chromatography. A new magnetic solid-phase extraction method for dye analysis yielded reasonable linearity (r â–¡ 0.99), low limits of detection (0.047-0.076 µg/L), and good precision within the analyte concentration range of 0.25-50 µg/L.

Synthesis of 3D magnetic porous carbon derived from a metal-organic framework for the extraction of clenbuterol and ractopamine from mutton samples.

3D magnetic porous carbon (MPCK) was prepared using the metal-organic framework (MOF) MIL-100(Fe) as the carbon precursor by carbonisation and KOH activation strategies. Carbonisation and activation ensured that MPCK possessed excellent structural and thermal stability, strong magnetic responsiveness and high surface area. MPCK was used as an adsorbent for the magnetic solid-phase extraction of clenbuterol and ractopamine from mutton samples. The concentration levels of analytes were determined by ultra-high performance liquid chromatography-mass spectrometry. Under optimised extraction conditions, the peak area responded linearly to analytes over the concentration range from 0.05 µg L-1 to 40 µg L-1 (r ≥ 0.9972). The detection limits of clenbuterol and ractopamine were found to be 0.130 µg kg-1 and 0.150 µg kg-1, respectively. The satisfactory recoveries in mutton samples ranging from 95.64% to 114.65% indicated that 3D porous carbon is a promising adsorption material for the extraction of clenbuterol and ractopamine from complex biological matrixes.

Changes in starch structures and in vitro digestion characteristics during maize (Zea mays L.) germination.

This study analyzed changes in the starch structures and in vitro digestion profiles of a specific maize cultivar, Jike 728 (JK728), in Jilin, China, after 0-5 days of germination. The total starch, amylose, and amylopectin contents decreased significantly during germination. The average molecular weight of the starch compounds also decreased significantly during germination. The proportion of amylopectin with a degree of polymerization (DP) of 13-24 significantly decreased, while the relative abundance of amylopectin with DP values of 6-12, 25-36, and 37-60 significantly increased. The X-ray diffraction (XRD) patterns of all samples were characteristic of A-type starch, and the starch relative crystallinity decreased over time. The proportions of slowly digestible starch and resistant starch decreased significantly, while the proportion of rapidly digestible starch increased significantly during germination. Germination is an easy, inexpensive, and low-carbon processing method. This study indicates that germination is an effective way to control the physical properties and digestibility of starch in maize. The changes observed in the physical properties and digestibility of maize starch after germination provide scientists with a platform to understand starch modification mechanisms that might have potential applications on an industrial scale.