Determination of UV filters in river water samples by in‐line SPE‐CE‐MS

The use of SPE coupled in‐line to CE using electrospray MS detection (in‐line SPE‐CE‐ESI‐MS) was investigated for the preconcentration and separation of four UV filters: benzophenone‐3, 2,2‐dihydroxy‐4‐methoxybenzophenone, 2,4‐dihydroxybenzophenone and 2‐phenylbenzimidazole‐5‐sulphonic acid. First, a CE‐ESI‐MS method was developed and validated using standard samples, obtaining LODs between 0.06 μg/mL and 0.40 μg/mL. For the in‐line SPE‐CE‐ESI‐MS method, three different sorbents were evaluated and compared: Oasis HLB, Oasis MCX, and Oasis MAX. For each sorbent, the main parameters affecting the preconcentration performance, such as sample pH, volume, and composition of the elution plug, and sample injection time were studied. The Oasis MCX sorbent showed the best performance and was used to validate the in‐line SPE‐CE‐ESI‐MS methodology. The LODs reached for standard samples were in the range between 0.01 and 0.05 ng/mL with good reproducibility and the developed strategy provided sensitivity enhancement factors between 3400‐fold and 34 000‐fold. The applicability of the developed methodology was demonstrated by the analysis of UV filters in river water samples.     

基于Diels-Alder点击反应构建壳聚糖-O-聚乙二醇接枝共聚物

通过Diels-Alder(D-A)反应,合成了具有规整化学结构的接枝共聚物,壳聚糖-O-聚乙二醇(CS-O-PEG).D-A反应所需双烯体(呋喃环)通过糠基硫醇与端甲基丙烯酸酯聚乙二醇之间的巯基-丙烯酸酯(thio-acrylate)反应合成得到;马来酰亚胺基丙酸通过活泼酯法偶联到十二烷基硫酸钠-壳聚糖复合物(SCC)羟基上,从而获得亲双烯体.采用红外光谱(FTIR)和核磁共振(1H-NMR)表征了中间产物与最终产物的结构,并用原位核磁监测D-A反应及其逆反应过程.结果表明,聚乙二醇双烯体可在水介质中温和条件下定量接枝到壳聚糖羟基上,反应具有点击特征;同时,聚乙二醇与壳聚糖之间的连接键在高温下(90℃)可通过D-A逆反应而发生断裂.     

基于电纺丝法的In2O3/CdO复合材料的制备及甲醛气敏特性

用静电纺丝法制备了In(NO₃)₃/聚乙烯吡咯烷酮(PVP)纺丝前驱物, 然后分别在500、600、700℃时烧结得到三种In₂O₃ 纳米纤维. 通过X 射线衍射(XRD)仪、热重差热分析(TG/DTA)、场发射扫描式电子显微镜(FE-SEM)表征结果得知, 500℃时In₂O₃的晶相已经形成, 且粒径为最小, 约为24 nm, 纳米纤维呈介孔结构.将三种烧结温度的In₂O₃纤维制作成气敏元件, 测试对比了三种元件对甲醛气体的敏感特性, 结果表明, 500℃烧结得到的In₂O₃纳米纤维在工作温度为240℃时响应最好, 对浓度为10×10^-6 (体积分数, φ)甲醛的响应为7.用静电纺丝法合成了CdO 纳米颗粒, 通过XRD、SEM 表征得知CdO 呈粒径约为68 nm 的颗粒. 将In₂O₃和CdO以不同摩尔比(1:1, 10:1, 20:1)复合, 对比测试了纯In₂O₃及三种In₂O₃/CdO复合材料对应的气敏元件对甲醛的气敏特性, 测试结果表明当In₂O₃纳米纤维与CdO纳米颗粒以摩尔比10:1 复合时, 元件的工作温度较低(200℃), 且对甲醛表现出最佳的气敏特性, 对浓度为10×10^-6甲醛的响应为13.6, 响应/恢复时间为140 s/32s. 最后对不同摩尔比复合的In₂O₃/CdO对甲醛的气敏机理进行了初步分析.     

Light-induced cis/trans isomerization of cis-[Pd(L-S,O)2] and cis-[Pt(L-S,O)2] complexes of chelating N,N-dialkyl-N′-acylthioureas: key to the formation and isolation of trans isomers

Irradiation cis-[M(Lⁿ-S,O)₂] complexes (M = Pt^II, Pd^II) derived from N,N-dialkyl-N′-benzoylthioureas (HLⁿ) with various sources of intense visible polychromatic or monochromatic light with λ < 500 nm leads to light-induced cis?→?trans isomerization in organic solvents. In all cases, white light derived from several sources or monochromatic blue-violet laser 405 nm light, efficiently results in substantial amounts of the trans isomer appearing in solution, as shown by ¹H NMR and/or reversed-phase HPLC separation in dilute solutions at room temperature. The extent and relative rates of cis/trans isomerization induced by in situ laser light (λ = 405 nm) of cis-[Pd(L²-S,O)₂] was directly monitored by ¹H NMR and ¹⁹⁵Pt NMR spectroscopy of selected cis-[Pt(L-S,O)₂] compounds in chloroform-d; both with and without light irradiation allows the δ(¹⁹⁵Pt) chemical shifts cis/trans isomer pairs to be recorded. The cis/trans isomers appear to be in a photo-thermal equilibrium between the thermodynamically favored cis isomer and its trans counterpart. In the dark, the trans isomer reverts back to the cis complex in what is probably a thermal process. The light-induced cis/trans process is the key to preparing and isolating the rare trans complexes which cannot be prepared by conventional synthesis as confirmed by the first example of trans-[Pd(L-S,O)₂] characterized by single-crystal X-ray diffraction, deliberately prepared after photo-induced isomerization in acetonitrile solution.     

Cinnamic acid hydrogen bonds to isoniazid and N′‐(propan‐2‐ylidene)isonicotinohydrazide,an in situ reaction product of isoniazid and acetone

A new polymorph of the cinnamic acid–isoniazid cocrystal has been prepared by slow evaporation, namely cinnamic acid–pyridine‐4‐carbohydrazide (1/1), C₉H₈O₂·C₆H₇N₃O. The crystal structure is characterized by a hydrogen‐bonded tetrameric arrangement of two molecules of isoniazid and two of cinnamic acid. Possible modification of the hydrogen bonding was investigated by changing the hydrazide group of isoniazid via an in situ reaction with acetone and cocrystallization with cinnamic acid. In the structure of cinnamic acid–N′‐(propan‐2‐ylidene)isonicotinohydrazide (1/1), C₉H₈O₂·C₉H₁₁N₃O, carboxylic acid–pyridine O—H...N and hydrazide–hydrazide N—H...O hydrogen bonds are formed.     

近红外二区活体荧光成像在肿瘤诊疗中的应用

由于具备组织穿透深度深和时空分辨率高等优势, 近年来近红外二区(Near-infrared-Ⅱ, NIR-Ⅱ, 1000~1700 nm)荧光成像技术得到了快速发展, 其在肿瘤临床诊断和治疗的潜力更是引发了广泛关注. 本文首先阐释了NIR-Ⅱ窗口荧光成像的原理及其优势, 随后根据结构分类归纳总结了现有荧光团的特征, 重点介绍了荧光探针在性能优化上的进展以及在肿瘤早期检测、 术中导航和光疗中的应用, 最后讨论了现有NIR-Ⅱ 荧光探针的局限以及临床转化面临的挑战, 并对未来的发展方向进行了展望.     

Development of fish gelatin-based artificial fish baits incorporating bioattractants from seafood processing waste

The study dealt with evolving an artificial fish bait by incorporating bioattractant concentrates derived from seafood processing wastes by enzymatic hydrolysis namely fish waste concentrate (FWC), squid waste concentrate (SWC), and shrimp processing concentrate (SPWC). They were characterized based on amino acid content and presence of different functional groups using FTIR. Among them, SWC was found to have the highest amino acid content of 60.85mg/100 mg followed by FWC (42.21mg/100 mg) and SPWC (24.82mg/100 mg). The developed artificial fish baits were subjected to protein leaching, solubility in seawater besides testing for acceptability by the red snapper. The study revealed that the bait incorporated with SWC at 3% level was found be the most ideal, with the protein leaching rate of 24.82 mg/g/h, solubility rate of 36.6 mg/g/h and the attractability score of 29/30. The amino acid leaching rate was 3.11 mg/h/100 mg and it was found to contain five amino acids such as glycine, proline, glutamic acid, alanine and serine. The study revealed that the hydrolyzed squid waste concentrate can be incorporated at 3% (w/w) with fish gelatin based biomatrix during gelation to prepare artificial bait.     

In2BP3O12:Cr3+宽带近红外荧光粉的发光性能及应用研究※

近红外光谱技术在安防监控、食品检测、生物成像、农业等领域具有重要应用价值, 而开发出紧凑高效的近红外光源是其大规模商业应用的前提. 荧光粉转换型近红外发光二极管(light emitting diodes, LED)光源具有结构紧凑、成本低、使用寿命长、发射光谱可调等优点, 因此近些年受到广泛关注, 其关键就在于开发出能被蓝光有效激发的高性能近红外荧光粉. 本工作利用高温固相法制备了一种新型宽带近红外荧光粉In₂BP₃O₁₂:Cr³⁺, 在480 nm激发下, 荧光粉发射峰值位于950 nm, 光谱覆盖了750~1350 nm范围, 半峰宽达到210 nm. 采用该荧光粉与商用蓝光InGaN LED芯片封装, 获得了具有宽带发射的近红外LED光源, 在60 mA的驱动电流下, 近红外光辐射功率为5 mW. 当采用该光源照射人的手掌, 用近红外电感耦合器(charge coupled device, CCD)相机能够对手掌中的血管进行清晰的成像. 上述结果表明该近红外荧光粉可用于制备基于蓝光芯片的宽带近红外LED光源, 并在生物医学等领域具有潜在应用前景.