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High-throughput single-cell analysis is critical to elucidate the cell heterogeneity. Recently, droplet microchips using oil/gas phases to generate single-cell encapsulated droplets have been combined with inductively coupled plasma-mass spectrometry (ICP-MS) for determination of trace elements in single cells with a throughput of dozens of cells per min. To improve the sample throughput and avoid the oil phase introduced into ICP-MS, herein, a negative magnetophoresis focusing microchip was established and online-coupled to ICP-MS for single-cell analysis. MCF-7 cells in the paramagnetic salt solution were introduced into the designed focusing microchannel, in which they were focused into a single stream under both the magnetic repulsion force and inertial lift force, and then were introduced into ICP-MS for online single-cell analysis. The important parameters including the chip design, the concentration of the paramagnetic salt solution, flow rate, cell density, and dwell time were optimized. Under the optimal conditions, a high sample throughput of 1390 cells min

ObjectivesTo assess the characteristics of the global death burden imposed by chronic kidney disease (CKD) and the attributable risk factors from 1990 to 2019 to help inform a framework for policy discussions, resource allocation and research priorities.DesignA population-based observational study.SettingThe death data and relative risk factors were obtained from the Global Burden of Disease (GBD) Study 2019 database.Main outcome measuresBased on the GBD database, we estimated the death burden attributable to CKD stratified by sociodemographic index (SDI), geographic location, sex, age group, time period and risk factors from 1990 to 2019.ResultsOver three decade study period, the global number of CKD-related deaths increased from 0.60 million (95% uncertainty interval (UI): 0.57–0.63 million) in 1990 to 1.43 million (95% UI: 1.31–1.52 million) in 2019. The age-standardised death rate (ASDR) of CKD, among all causes, increased from 15th in 1990 to 10th in 2019. Globally, the ASDR in males was higher than that in females. CKD-related deaths mainly occurred in those aged over 50 years, especially in regions with higher SDIs. The ASDR was negatively related to SDI (ρ=−0.603, pConclusionsCKD-related deaths continue to increase, with the majority occurring in elderly adults. The CKD-related death burden is higher in males than in females. Additionally, the increasing high-temperature-related death burdens in lower SDI regions should receive social attention.

A dual column packed with a magnetic metal-organic framework composite (MFC) and mercapto-functionalized MFC nanoparticles (MFC-SH) in microfluidic chip channels is described for array chip-based magnetic solid phase microextraction of arsenic species including arsenite [As(III)], arsenate [As(V)], monomethylarsonous acid (MMA) and dimethylarsinic acid (DMA) in SCC-7 cells. At pH 6, the MFC-SH adsorbs As(III) while MFC quantitatively adsorbs As(V), DMA and MMA. The As(III) adsorbed on the MFC-SH can be desorbed with a 2% solution of thiourea in 0.5 M HNO3. The arsenic species MMA, DMA and As(V) are retained on the MFC but can be desorbed by ammonia. A sequential elution strategy was employed to elute MMA, DMA, As(V) and As(III) one by one for subsequent on-line determination by ICP-MS. The limits of detection are 4.8, 6.3, 3.8 and 7.1 ng L−1 for As(V), DMA, MMA and As(III), respectively. The enrichment factors are between 23 and 25, and the throughput is 7 samples per hour. The arsenic species in (spiked) SCC-7 cell samples were analyzed by the online system with adequate recoveries (89–110%).

This review focuses on magnetic nanomaterials as sorbents for trace elements analysis in environmental and biological samples. The design and preparation of magnetic nanomaterials with specific functional groups for trace elemental analysis are summarized, along with relevant adsorption mechanism. The application of these magnetic sorbents in different operation modes for the quantification of trace elements and their species in environmental and biological samples are discussed. The trend of development in this field is also prospected.

Porous organic frameworks (POFs) are an exciting emerging type of porous organic materials in which molecular building blocks are linked by covalent bonds. POFs usually have high thermal and chemical stability, large surface area, artificially regulated pore size distribution and abundant functional groups, which are considered to be ideal and efficient adsorbent for diverse compounds. They are an excellent alternative for sorbents/coating-based sample pretreatment techniques. In this review, the application of various POFs in trace analysis is discussed in terms of pretreatment techniques, including solid phase extraction, magnetic solid phase extraction, solid phase microextraction, capillary microextraction and stir bar sorptive extraction. The POFs-based sorbents/coatings are reviewed, with the focus on the construction process, comparison among POFs and between POFs and common sorbents, adsorption mechanism for specific analytes and the adsorption performance in trace analysis. Current research status indicate that much effort would be paid on further exploration of the relationship between the special properties of POFs (e.g., crystal form, pore structure) and the adsorption behavior, directional design and synthesis of POFs involved sorbents/coating for trace analysis of organic substances and elemental species, and the development of POFs-involved analytical methodologies for quantification of interest analytes.

A chip-based array is described for magnetic solid-phase microextraction (MSPME) of the ions of Pt, Au and Bi. Magnetic porous organic polymers (MOPs) prepared from magnetite nanoparticles and 1,3,5-tris(4-aminophenyl)benzene are introduced as a novel adsorbent. Eight solid phase extraction columns packed with MOPs were integrated in parallel on a microfluidic chip for array microextraction. After elution with a 12% (m/v) solution of cysteamine hydrochloride (pH 8.0), the eluent is introduced into an ICP-MS instrument for quantification. Under the optimized conditions, the limits of detection for Pt, Au and Bi are 8.6, 4.4 and 3.4 ng L−1, respectively. The sample throughput is 7 h−1, and the adsorption capacities are 32, 24 and 24 μg mg−1 for Pt, Au and Bi, respectively. The method was validated by the determination of Bi in a certified reference material (GSH-1A; human hair), and the values obtained coincided with the certified value. This method was also applied to the determination of Pt, Au and Bi in (spiked) urine and cell samples, and good recoveries (85.8–113%) were achieved. The method is highly sensitive and has a high throughput and a low sample/reagent consumption (with 500 HeLa cells consumed).

Based on two promising p-CPhH4IDC and o-CPhH4IDC ligands, one 2D coordination polymer, [Ca(p-CPhH2IDC)(H2O)] n (p-CPhH4IDC = 2-(4-carboxylphenyl)-1H-imidazole-4,5-dicarboxylic acid) (I) and one novel dimeric complex, [Cd2(o-CPhH2IDC)2(H2O)6] · 4H2O (o-CPhH4IDC = 2-(2-carboxylphenyl)-1H-imidazole-4,5-dicarboxylic acid) (II) have been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectroscopy, and single crystal X-ray diffraction (CIF files CCDC nos. 929826 (I), 959841 (II)). Polymer I exhibits a graceful 2D grid sheet structure. Polymer II is a binuclear complex in which two Cd2+ ions are bridged by two carboxyates from two o-CPhH2IDC2– ligands. Four and two types of coordination environments around the Ca and Cd atoms, respectively can be observed. Furthermore, the solid-state photoluminescence and thermal properties of the two complexes have been investigated.

One newly prepared 3D polymer (1) composed of left- and right-handed helices containing [Cd8(p-ClPhHIDC)12(4,4′-bipy)6] cages shows selective pyridine recognition, with a visual colour change from pearl to pink under ultraviolet irradiation.

A 1-D coordination polymer, {[Pb(o-ClPhH2IDC)2]·H2O}n (o-ClPhH3IDC = 2-(2-chlorophenyl)-1H-imidazole-4,5-dicarboxylic acid) (1), a 2-D coordination polymer, [Pb3(p-ClPhIDC)2(H2O)]n (p-ClPhH3IDC = 2-(4-chlorophenyl)-1H-imidazole-4,5-dicarboxylic acid) (2), and a 3-D polymer, [Pb(p-ClPhH2IDC)2]n (3), have been obtained solvothermally and structurally characterized by elemental analyses, IR, and single-crystal X-ray diffraction. Although they were prepared with similar ligands and Pb2+, polymers 1–3 show distinct structures. The X-ray powder diffraction and thermal properties of the polymers have been investigated. The influence of the reaction conditions to the final products and coordination of the organic ligands are discussed.