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Trace levels of organic and inorganic lead and mercury species in the environment, including divalent lead (Pb2+), trimethyllead (TML), divalent mercury (Hg2+), monomethylmercury (MeHg), and ethylmercury (EtHg), are highly toxic to humans and ecology. It is of great importance for speciation of lead and mercury to evaluate the toxicity of lead and mercury and their biogeochemistry in the environment. However, simultaneous multi-elemental enrichment and speciation at trace level remains a challenge. There are few reports of simultaneous magnetic solid-phase extraction (MSPE) of organic and inorganic lead and mercury species at trace level in the real water. In this work, a novel core-shell magnetic hydrazine-linked covalent organic frameworks (Fe 3 O 4 @COF-TCH) was prepared for the first time by grafting hydrazine-linked COFs on the Fe 3 O 4 nanoparticles. Fe 3 O 4 @COF-TCH with abundant thione and imino groups has strong adsorption for lead and mercury species. Based on it, a simple and practical magnetic solid-phase extraction high-performance liquid chromatography-inductively coupled plasma mass spectrometry (MSPE-HPLC-ICP-MS) method was developed for extraction and determination of trace lead and mercury species, including Hg2+, MeHg, EtHg, Pb2+ and TML. The limits of detection (3δ) of the developed method were 0.08, 0.81, 0.90, 0.56 and 0.88 ng L−1 with the enrichment factors (EFs) of 384, 376, 379, 389 and 360-fold for Pb2+, TML, Hg2+, MeHg and EtHg, respectively. The high accuracy and reproducibility have been proved by the spiked recoveries (94.4–103 %) in real samples. The proposed method with simple operation and high sensitivity has been successfully applied to simultaneous speciation of lead and mercury at trace levels in the water samples with complicated matrices, including underground water, surface water, sea water. Meanwhile, it has the advantages of cost-saving, labor-saving and time-saving and is suitable for the investigation and risk assessment in water. The development of MSPE-HPLC-ICP-MS method provides ideas and guidance for the simultaneous multi-elemental enrichment and speciation. [Display omitted] • A core-shell magnetic hydrazine-linked COFs was prepared for the first time. • A MSPE-HPLC-ICP-MS method was developed for simultaneous enrichment and speciation of organic and inorganic lead and mercury. • Figures of merit: LODs (0.08–0.90 ng L−1), Linearity ranges (0.26–1000 ng L−1), RSD (<4.5 %). • The proposed method has excellent anti-interference ability. • The proposed method can be applied in the samples with complex matrix, such as seawater, surface water. [ABSTRACT FROM AUTHOR]

Pleurotus eryngii has been widely cultivated in China and massive spent mushroom substrate (SMS) has been discarded. To utilize spent substrate of P. eryngii effectively, SMS was extracted by hot alkali liquor and a high yield (12.18%) of crude polysaccharide (designated as CPS) was obtained, then a polysaccharide-protein complex (RPS) was purified from CPS. Molecular characterization detected by size exclusion chromatography/multi-angle laser light scattering (SEC-MALLS) showed that the weight average molar mass ( M w ) of RPS was 8.372 × 10 6 g/mol. The molecular conformation of RPS was revealed to be a rigid rod form in aqueous solution. Monosaccharide composition analysis by GC–MS confirmed that RPS is a novel acid heteropolysaccharide and mainly composed of xylose, glucose, and arabinose. Then, FT-IR spectral analysis of RPS revealed prominent characteristic polysaccharide and protein groups. Pharmacological experiments in vitro suggested that both CPS and RPS exhibited strong antioxidant activities in a dose dependent manner, using different in vitro models like ABTS, superoxide, hydroxyl and DPPH. The high-yield crude polysaccharide showed potential for application as strong antioxidant in food industry. The study provided a reliable approach for spent resource recovery, which would be significant to sustainable development of mushroom industry and environmental protection. [ABSTRACT FROM AUTHOR]

• Facile room-temperature synthesis of urchin-like magnetic COFs. • Thiol and thioether functionalized magnetic COFs with excellent adsorption capacity for mercury species (> 550 mg g−1). • Rapid MSPE process for inorganic mercury, monomethylmercury and ethylmercury. • Figures of merit: LOD (0.17-0.96 ng L−1), Linearity range (0.55-1000 ng L−1), RSD (<5.4 %). • The proposed method can be applied in the samples with complex matrix, such as seawater and biological samples. A simple and practical magnetic solid-phase extraction high-performance liquid chromatography-inductively coupled plasma mass spectrometry (MSPE-HPLC-ICP-MS) method for extraction and determination of trace mercury species, including inorganic mercury (IHg), monomethylmercury (MeHg) and ethylmercury (EtHg), was developed. The MSPE adsorbent, urchin-like thiol and thioether-functionalized magnetic covalent organic frameworks (Fe 3 O 4 @COF-S-SH), was synthesized by coating covalent organic frameworks (COFs) on the surface of Fe 3 O 4 nanoparticles at room temperature and then easily grafting 1,2-Ethanedithiol on the COFs. The as-prepared Fe 3 O 4 @COF-S-SH has strong adsorption capacity for IHg, MeHg and EtHg, with excellent static adsorption capacity: 571, 559 and 564 mg g−1, respectively. The parameters influencing the extraction and enrichment had been optimized, including pH, adsorption and desorption time, composition and amount of the eluent, co-existing ions and dissolved organic materials etc. Under the optimized condition, the limit of detection (3δ) of the proposed method were 0.96, 0.17 and 0.47 ng L−1 for IHg, MeHg and EtHg, and the developed method has high actual enrichment factors of 370, 395, 365-fold for IHg, MeHg and EtHg based on 200 mL samples, respectively. The high accuracy and reproducibility has been proved by the spiked recoveries (96.0‒108 %) in real water samples and determination of the certified reference material. Both the adsorption and desorption process can be completed within 5 min. The proposed method with simple operation, short pre-concentration time and high sensitivity has been successfully applied to mercury speciation at trace levels in the samples with complicated matrices, including underground water, surface water, sea water and fish samples. [ABSTRACT FROM AUTHOR]