Phthalate acid esters (PAEs), known food contaminants, can lead to reproductive problems, respiratory diseases, childhood obesity, and neuropsychological disorders. This work aims to develop an electrochemical aptamer sensor for the detection of DAP and its analogs. To achieve specific recognition ability for PAEs, we have introduced the thymidine-Hg2+-thymidine 2+-thymidine strategy for the first time in an electrochemical aptamer sensor, incorporating metal-organic frameworks (MOFs) as the carrier for the aptamer. Additionally, nano signal amplification technology was applied by immobilizing MXene on the electrode to intensify the sensor's current signal. In the presence of PAEs, these molecules specifically bound to the aptamers, resulting in competitive release of Hg2+ 2+ and aptamers connected to Hg2+, 2+ , subsequently reducing current signaling. Under optimal experimental conditions, the designed sensor achieved a linear range from 1.65 x 10-5-5 mg/mL to 3 x 10-3-3 mg/ mL and an extremely low detection limit of 8.94 x 10-6-6 mg/mL. Furthermore, it exhibited good reliability and practicality in detecting actual samples.

为实现水产品中抗生素和镇静剂的同时、快速检测,进行了题示研究.分取2.0 g匀浆后的样品的肌肉组织,加入体积比79:1:20的乙腈-乙酸-水混合溶液10 mL,振荡1 min,超声10 min.加入2.0 g氯化钠,振荡1 min,于-20℃保存30 min,用于去除提取液中的脂肪.离心10 min,分取1 mL上清液注入装载有150 mg C18的CAFS clean-up净化柱中,多次推动活塞,将提取液全部转移到2 mL离心管中.分取0.5 mL净化液,加入0.5 mL 0.1％(体积分数,下同)甲酸溶液,混匀后过0.22μm尼龙滤膜.滤液注入高效液相色谱-三重四极杆复合线性离子阱质谱仪,9种目标物在BEH C18色谱柱上用不同体积比的0.1％甲酸溶液和含0.1％甲酸的甲醇溶液的混合溶液进行梯度洗脱分离后,用电喷雾离子源正离子(ESI+)模式电离,多反应监测(MRM)模式检测,基质匹配法定量.结果显示,9种目标物的质量分数分别在1.0～50.0μg?kg-1(丁卡因、布比卡因、恩诺沙星和氧氟沙星)、2.0～50.0μg?kg-1(地西泮和氟罗沙星)、5.0～50.0μg?kg-1(环丙沙星、培氟沙星和洛美沙星)内与对应的峰面积呈线性关系,检出限为0.2～1.0μg?kg-1;对空白草鱼样品进行3个浓度水平的加标回收试验,回收率为99.1％～110％,测定值的相对标准偏差(n=6)分别为1.9％～8.2％(日内精密度试验)和2.6％～8.5％(日间精密度试验).方法用于28份水产品的分析,检出了1种镇静剂布比卡因(检出量为1.41μg?kg-1)以及4种氟喹诺酮类抗生素[洛美沙星、培氟沙星、环丙沙星(3种抗生素检出量均低于测定下限)和恩诺沙星(检出量为2.43～4.61μg?kg-1,低于GB 31650-2019规定的限量)].

Prochlorococcus is an obligate marine microorganism and the dominant autotroph in tropical and subtropical open ocean. However, the salinity range for growing and response to low salinity exposure of Prochlorococcus are still unknown. In this study, we found that low-light adapted Prochlorococcus stain NATL1A and high-light adapted strain MED4 could be acclimated in the lowest salinity of 25 and 28 psu, respectively. Analysis of the effective quantum yield of PSII photochemistry (Fv/Fm) indicated that both strains were stressed when growing in salinity lower than 34 psu. We then compared the global transcriptome of low salinity (28 psu) acclimated cells and cells growing in normal seawater salinity (34 psu). The transcriptomic responses of NATL1A and MED4 were approximately different, with more differentially expressed genes in NATL1A (525 genes) than in MED4 (277 genes). To cope with low salinity, NATL1A down-regulated the transcript of genes involved in translation, ribosomal structure and biogenesis and ATP-production, and up-regulated photosynthesis-related genes, while MED4 regulated these genes in an opposite way. In addition, both strains up-regulated an iron ABC transporter gene, idiA, suggesting low salinity acclimated cells could be iron limited. This study demonstrated the growing salinity range of Prochlorococcus cells and their global gene expression changes due to low salinity stress.

目的 建立一种基于滤过型净化柱净化,结合超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)测定草鱼肌肉冻干粉中4种硝基呋喃类代谢物的快速检测方法.方法 制备阴性草鱼肌肉冻干粉作为检测目标.样品经水解、衍生化并提取浓缩后,采用以50 mg C18为净化填料的CAFS clean-up净化柱对复溶液进行1次快速净化,超高效液相色谱分离,三重四极杆/复合线性离子阱质谱仪进行测定,内标法定量分析.结果 4种硝基呋喃类代谢物在其相应的质量浓度范围内线性关系良好(r>0.999),定量限为0.6～2.4μg/kg;样品中添加定量限、2.5、5.0和50.0μg/kg浓度水平时的平均回收率在81.3％～115.1％之间,相对标准偏差为1.5％～13.1％.结论 该方法经济、简便、高效,灵敏度高,重复性好,可作为草鱼肌肉冻干粉中4种硝基呋喃类代谢物的基体标准物质的检测方法.

A multi-residue analysis of six diacylhydrazine insecticides in water, sediment, and aquatic products was established by liquid chromatography triple quadrupole tandem mass spectrometry (LC-MS/MS). The water sample was extracted with acetonitrile by low-temperature enrichment liquid-liquid extraction technology. The sediment and aquatic products were prepared using QuEChERS technique. Method validation showed perfect linearity with correlation coefficients (R) more than 0.9992 for all insecticides, and the matrix effects were nearly negligible (−1.42% to −0.27%) for water, sediment and aquatic products. The recoveries were 80.0–99.7% at three spiked levels (0.02 ng·mL−1, 0.1 ng·mL−1, 0.5 ng·mL−1; 2.0, 10, and 50 ng·g−1) and the precisions (intra-day and inter-day precision) were lower than 5.28%, with the low LODs (3.8 ~ 9.6 pg·mL−1; 0.38–0.96 ng·g−1) and LOQs (12.7 ~ 32.0 pg·mL−1; 1.27–3.20 ng·g−1) for water, sediment, and aquatic products, indicating the good accuracy and precision of the proposed method. The applicability, efficiency, and sensitivity of this method have been proved in the analysis of six diacylhydrazine insecticides in water, sediment, and crucian carp in Rice- crucian carp - integrated planting system.

Covalent organic frameworks (COFs) have received widespread interest due to their high porosity, excellent crystallinity, tailorable structures, and broad application prospects. It has been demonstrated that proper combination and arrangement of electron donor and acceptor units in 2D conjugated COF lattice could promote efficient charge separation and electron transfer, and thus is beneficial for photocatalysis. In this article, three donor-acceptor (D-A) 2D COFs were prepared by Schiff base reaction of electron acceptor 4,4′,4″,4‴-(benzo[1,2-d:4,5-d′]bis(oxazole)-2,4,6,8-tetrayl)tetraaniline (BBO) with different electron donors: thieno[3,2-b]thiophene-2,5-dicarbaldehyde (TT), benzo[1,2-b:4,5-b′]dithiophene-2,6-dicarboxaldehyde (BDT) and terephthalaldehyde (Ph), respectively. These D-A 2D COFs exhibited prominent photocatalytic activity towards α-oxyamination of 1,3-dicarbonyl with 2,2,6,6-tetramethyl-1-piperdinyloxy (TEMPO) upon visible light irradiation. Among these D-ABBO-COFs, DTT-ABBO-COF exhibited the highest photocatalytic rates, which can be ascribed to the more negative highest occupied molecular orbital (HOMO) and narrower bandgap. The excellent stability, high activity and superior recyclability render DTT-ABBO-COF as a potential and environmentally friendly heterogeneous catalyst for α-oxyamination.

中国鲜活水产品市场增长迅猛,但产销地域差别明显,长距离运输需求显著.镇静剂能够抑制机体的新陈代谢,降低鲜活水产品应激反应,其被应用于水产品运输、繁育和手术等环节,以提高水产品的成活率.但是镇静剂在水产品中广泛使用而可能导致的残留问题已经引起了国内外研究人员的关注.本文对水产品中镇静剂残留检测技术研究进展进行了概述,以期为后续研究提供参考.对水产品中镇静剂的类型及使用规定进行了介绍,分析并总结了近10年来水产品中镇静剂类药物的检测研究进展.论述了水产品中镇静剂残留检测样品前处理方法、高效液相色谱检测方法、高效液相色谱串联质谱法和气相色谱串联质谱法进展,归纳了相关方法的优缺点,并对其发展做出展望.在目前研究的基础上,未来应在新型简单、高效样品前处理方法方面开展更深入的研究,为水产品质量安全监管提供技术支撑.

南极磷虾(Euphausia superba)以其庞大的生物量和潜在的渔业资源价值广泛受到世界各国的重视.南极磷虾因富含蛋白质已成为人类重要的优质生物蛋白库,此外,其还含有脂质、矿物质等营养物质、虾青素及甲壳素等活性物质.目前,高氟含量一直是制约南极磷虾大规模加工利用的瓶颈.南极磷虾在加工利用过程中伴有氟元素的迁移现象,甲壳中的氟元素会向肌肉中迁移,严重影响南极磷虾的食用价值.科学评价氟迁移对南极磷虾的加工局限性并开发更多的高值产品已成为亟需解决的问题.本研究对影响南极磷虾中氟元素迁移的因素进行归纳,旨在为南极磷虾的进一步开发利用及磷虾产业链的发展提供参考.

The detection of dopamine, one of the neurotransmitters in cerebral physiology, is critical in studying brain activities and understanding brain functions. However, regenerative biosensor for monitoring dopamine in the progress of physiological and pathological events is still challenging, due to lack of the platform for repetitive online detection-regeneration cycle. Herein, we have developed a regenerated field effect transistor (FET) combined with in vivo monitoring system. In this biosensor, gold-coated magnetic nanoparticles (Fe3O4@AuNPs) acts as a regenerated recognition unit for dopamine. Just by simple removal of a permanent magnet, dopamine on the biosensor interface are catalyzed by tyrosinase, thus achieving the regeneration of the biosensor. As a result, this FET biosensor not only reveals high sensitivity and selectivity, but also exhibits excellent stability after 15 regeneration processing. This biosensor is capable of monitor dopamine with a linear range between 1 mu mol L-1 and 120 mu mol L-1 and low detection limit (DL) of 3.3 nmol L-1. Then, the platform has been successfully applied in dopamine analysis in fish brain under global cerebral cortical neurons. This FET biosensor is the first to on-line and remote control the sensitivity and DL by permanent magnet. It opens the door to reusable, inexpensive and large-scale productions.

Metal-organic frameworks (MOFs) have potential as heterogeneous biomimetic catalysts due to their high surface area, tunable porosity, and diversity of metals and functional groups. However, the activity and substrate specificity of pure monomeric MOFs still must be improved. Here, a size-selective MOF coating on the external surface of a biomimetic MOF is used to overcome these limitations of pure monomeric MOFs. The synthesis process of the biomimetic material involved first the coating of porous coordination network (PCN-222) cores with polyvinylpyrrolidone (PVP) as a structure-directing agent and then the modification of zeolitic imidazolate frameworks (ZIF-8). The yolk/shell PCN-222@ZIF-8-based sensor showed high selectivity for catechol but not for dopamine or L-DOPA. The PCN-222@ZIF-8 hybrid material-based sensor displayed 10 times more sensitivity than the PCN-222-based sensor, with low limit of detection (LOD) at 33 nmol L-1. Thus, ZIF-8 is a shell which allows the diffusion of specific substrate to the active sites of the PCN-222 and enriches the substrate. Furthermore, the PCN-222@ZIF-8 exhibits solvent adaptability, which overcomes the drawback of the natural HRP enzyme. This work opens a new avenue for construction of MOF@MOF biomimetic sensors and other applications.

Copper is a common element in the environment and human body. Exposure to high concentrations of Cu2+ potentially causes health issues, such as Wilson and Alzheimer's diseases. It is of great importance for the highly selective and sensitive detection of Cu2+. In this work, a porous metal-organic framework (MOF), PCN222, is employed for the selective and sensitive determination of Cu2+. The selectivity of PCN222 relies on the interaction between Cu2+ and the porphyrin core of PCN222. PCN222 stacked with porphyrin rings exhibits solvent adaptability, which overcomes the drawback of the natural porphyrinic enzyme (such as HRP). PCN222 is used for constructing a sensor which shows a linear range of Cu2+ concentration from 0.4 to 13 μmol L-1, and its limit of detection (LOD) is 50 nmol L-1. The response time is less than 3 s, which is faster than previous methods. This work opens up a new route to MOF applications in the detection of metal ions in complex environments.

Single-walled carbon nanotube-based field effect transistors (SWCNT-FETs) are ideal candidates for fabricating sensors and have been widely used for chemical sensing applications. SWCNT-FETs have low selectivity because of the environmentally sensitive electronic properties of SWCNTs, and SWCNT-FETs also show a high noise signal and poor sensitivity because of charge trapping from Si-OH hydration of the SiO2/Si substrate on the SWCNTs. Herein, poly (4-vinylpyridine) (P4VP) was used for noncovalent attachment to SWCNTs and selective binding to copper ions (Cu2+). Importantly, the introduction of a hafnium-oxide (HfO2) layer through atomic layer deposition (ALD) overcame the charge trapping by SiO2 hydration and remarkably decreased the interference signal. The sensitivity of the P4VP/SWCNT/HfO2-FET sensor for Cu2+ was 7.9 μA μM-1, which was approximately 100 times higher than that of the P4VP/SWCNT/SiO2-FET sensor, and its limit of detection (LOD) was as low as 33 pmol L-1. Thus, the P4VP/SWCNT/HfO2-FET sensor is a promising candidate for the development of Cu2+-selective sensors and can be designed for the large-scale manufacturing of custom-made sensors in the future.

Exposure to even very low concentration of Pb2+ can cause neurological and developmental disorders, and affects children more severely. Neuromelanin (NM) in the substantial nigra can trap endogenous and environmental toxins and immobilize them as stable adducts, thus protecting brain against toxicity. Until now, the structure and Pb2+-chelating ability of NM is still little understood. Here, we prepare a mimicking NM by amino acid and dopamine. The prepared NM has strong fluorescent and its fluorescence can be quenched by Pb2+. This study offers a novel way to synthetic NM and provides an effective method to detect Pb2+.

建立了测定青蟹中6种砷形态的高效液相色谱-电感耦合等离子体质谱联用方法,砷形态包括亚砷酸盐、砷酸盐、一甲基砷酸、二甲基砷酸、砷胆碱、砷甜菜碱.对提取溶剂、时间和流动相的种类、pH值、洗脱方式等参数进行优化,采用基质加标法对目标物进行定量.研究确定青蟹样品以0.5 mmol/L的碳酸铵-甲醇(V:V=99:1)为提取液,超声水浴法提取30 min,正己烷去脂,提取液过微孔滤膜后,选用阴离子交换柱为分离柱,使用50 mmol/L碳酸铵-甲醇(V:V=99:1)溶液为流动相梯度洗脱,ICP-MS定性定量分析.方法学验证表明,砷甜菜碱在0.5～500μg/L范围内、 其余5种在0.5～20μg/L范围内线性关系良好,加标回收率范围为76％～118％,相对标准偏差范围为2.4％～9.5％,方法检出限为0.01～0.05 mg/kg.用砷形态标准物质(BCR-627)对方法进行验证,测定结果均在参考值范围内;实际青蟹样品测定结果表明,青蟹中的砷形态主要以砷甜菜碱存在.此法前处理简单,分离度好,适合蟹类中6种砷形态化合物的定量分析.

Pyrolysis, an effective recycle strategy for resins or plastic containing tetrabromobisphenol A (TBBPA), often lead to formation of more toxic decomposition chemicals. Online collection coupled with off-line analysis for qualitative and quantitative analysis of the residue often induce information loss of these pyrolysis products. In this study, a temperature controllable thermal decomposition device coupled with an ambient mass spectrometry was directly employed for on-line monitoring of the pyrolysis process of TBBPA. Thermal products through debromination, methylation, methoxylation and beta-scission have all been detected. Based on the mass spectra of TBBPA decomposition products, the number of bromine atoms and the m/z values, about 8 brominated decomposition products/intermediates have been identified. Temperature played the critical role for the pyrolysis processes. It was found that almost no TBBPA degraded at low temperature (100-150 degrees C), intensified decomposition happened at about 300 degrees C and small molecules formed in large quantities at > 450 degrees C.

在单因素实验的基础上,以舌状蜈蚣藻多糖得率为指标,选择料液比、温度和时间进行响应面实验,确定最佳工艺条件,同时测定舌状蜈蚣藻多糖对1,1-二苯基-2-三硝基苯肼(DPPH)自由基以及羟自由基(·OH)的清除能力.结果显示,舌状蜈蚣藻多糖的最佳提取工艺为料液比1:37 g/mL,提取温度100℃,提取时间4 h,此时的多糖得率为15.23％.舌状蜈蚣藻多糖清除DPPH自由基和羟自由基的半抑制质量浓度(IC50)分别为12.61 mg/mL和2.05 mg/mL,具有较好的体外抗氧化活性.

Selective adsorption via the size matching effect is one of the most effective strategies for separating and analyzing low levels of organic molecules. Herein, multicomponent covalent organic frameworks (MC-COFs) with tunable pore sizes are constructed by using one knot (1,3,5-triformylphloroglucinol, Tp) and two organic linkers (p-phenylenediamine, Pa; benzidine, BD). The pore sizes of the MC-COFs composed of TpPaBDX (X = [BD]/([Pa] + [BD]) × 100 = 0, 25, 50, 75, and 100) range from 0.5-1.5 to 0.5-2.2 nm due to variations in the initial organic linker ratios. When coupling TpPaBDX-based solid-phase microextraction (SPME) with constant flow desorption ionization mass spectrometry (CFDI-MS), these MC-COFs feature better selective adsorption performance for tetrabromobisphenol A (TBBPA) derivatives than TpPa with a smaller pore size, TpBD with a larger pore size and even some commercial fibers (e.g., polydimethylsiloxane/divinylbenzene (PDMS/DVB)-, polyacrylate (PA)- and PDMS-coated fibers). The improved method involving MC-COF TpPaBD50 also presents favorable stability with relative standard deviations (RSD, 1 μg L-1) for single fibers of 5.5-7.9% (n = 7) and fiber-to-fiber of 6.6-7.8% (n = 7). Due to the decreased limits of detection and quantification (0.5-12 and 1.6-40 ng L-1), and reduced separation and detection time (7 min), ultratrace levels of TBBPA derivatives in real water samples are successfully detected. The proposed method shows great potential for the rapid tracing of the distribution, transportation and transformation of TBBPA derivatives to better understand their ecotoxicological effects in environmental media.

Oxytocin (OT) and dopamine (DA) are two important elements that are closely related to mental and reward processes in the brain. OT controlled DA functional regulation contributes to various behaviours such as social reward, social cognition and emotion-related behaviours. Previous studies indicated that diminished dopaminergic transmission in the medial prefrontal cortex (mPFC) is correlated with the pathophysiology of depression. However, the interaction of OT and DA and their roles in antidepressant effects still require further exploration. Here, we investigated the antidepressant effect of OT through local mPFC administration, and further explored the underlying mechanisms that indicated that OT could strengthen dopaminergic synaptic transmission with OT receptor (OTR) activation dependent in the mPFC. Our results showed that local administration of OT in the mPFC exerts antidepressant (-like) effects in both naïve and social defeat stress (SDS) depressive animal model. Mechanism study suggested that OT enhances DA level with OTR activation dependent, and elevated mPFC DA levels might further enhance excitatory synaptic transmission by activating the D1/PKA/DARPP32 intracellular signalling pathway in the mPFC. Hence, our study revealed that the activation of OTR strengthens excitatory synaptic transmission via the potentiation of dopaminergic synaptic transmission, especially via D1R activation dependent, in the mPFC, which may be the underlying mechanism of antidepressant (-like) effects mediated by OT. With specifically activation of the D1/PKA/DAPRR32 signalling pathway, our results may augment the important role of OT in reward circuits in the central nervous system.

A simple, green and nondestructive method based on terahertz fingerprint peaks has been developed for rapid in situ analysis of L-histidine and alpha-lactose in dietary supplements. Fingerprint absorption peaks of L-histidine and alpha-lactose located at 0.77 and 0.53 THz could be directly used for identification and quantitation of these analytes in commercial dietary supplements. Compared with the partial least squares regression model (PLSR), the linear least squares regression (LLSR) method based on peak areas presented better performance, with the linear correlation coefficients of 0.9899 and 0.9910 for L-histidine and alpha-lactose, respectively. Furthermore, analysis time per sample can be shortened to less than 1 min due to the narrower spectral acquisition region. The accuracies were 94.8-110% and 98.9-110%, comparable to those of ion chromatography for L-hisddine and high-performance liquid chromatography for alpha-lactose. The results presented great potential of the developed method for rapid in situ analysis of nutrients in dietary supplements.