碱木质素碳点的制备及对Fe3+检测性能研究

以碱木质素（Alkali lignin,AL）为碳源、乙二胺（Ethanediamine,EDA）为钝化剂、双氧水（H₂O₂）为氧化剂,利用简单、绿色、高效的水热法制备碱木质素碳点（ALE-CDs）。以荧光性能为指标,通过单因素实验优选出ALE-CDs的最佳制备工艺。结果表明,ALE-CDs表面存在大量的羟基（—OH）、羧基（—COOH）和氨基（—NH₂）等官能团,在水中具有优良的分散性和稳定性,荧光量子产率及寿命分别为19.20%和6.03 ns。利用ALE-CDs为荧光探针检测不同金属离子,发现ALE-CDs对Fe³⁺表现出较好的选择性,荧光强度与Fe³⁺浓度（0~50 μmol/L）呈良好的线性关系,Fe³⁺检出限约为1.66 μmol/L。     

基于“碘-罗丹明B”复合型荧光探针返荧光猝灭法测定食用油碘值

韦氏液(ICl)中加入过量碘化钾生成可溶性碘(I3^-),I3^-对罗丹明B(RB)具有荧光猝灭作用,可使RB的荧光信号强度减弱甚至消失,而油脂中的不饱和键可将韦氏碘(I⁺)还原为I^-,使体系荧光信号再现,据此建立了以碘-罗丹明B缔合物为荧光探针返荧光猝灭测定油脂中碘值的新方法,在激发波长360 nm,发射波长580 nm条件下进行了“ICl-KI-RB”体系的荧光测定,样品加入前后体系荧光强度变化值体现了油脂不饱和度。结果表明,韦氏碘(I⁺)浓度在0~2 μmol/L范围内与体系荧光强度(F)有良好的线性关系,线性方程为F=230.8-100.1c(μmol/L),相关系数r=0.9845,韦氏碘(I⁺)检出限为3.2×10^-9mol/L,该标准曲线作为食用油碘值测定模型方程。方法用于食用油脂碘值的测定,结果令人满意。     

Fe3+存在下制浆中段废水好氧活性污泥的驯化

研究了Fe³⁺存在下处理制浆中段废水的好氧活性污泥的驯化过程。首先通过Fe³⁺对微生物生长曲线的影响确定Fe³⁺最佳用量为30 mg/L;然后在Fe³⁺用量为30 mg/L下,采用制浆中段废水对好氧活性污泥进行驯化,并设置不加Fe³⁺的空白组对照。结果表明,整个驯化过程中,加Fe³⁺组COD_Cr去除率和污染物去除率(以UV-254减少率表示)均高于空白组;驯化结束后,加Fe³⁺组和空白组COD_Cr去除率分别达78.2%和76.0%,污染物去除率分别为50.0%和37.7%。通过对脱氢酶活性的分析表明,加Fe³⁺组活性高于空白组。     

Fe3+对好氧活性污泥理化特性的影响

探讨了Fe³⁺对好氧活性污泥理化特性的影响。结果表明：与对照样(不加Fe³⁺)相比,整个驯化过程中,加Fe³⁺反应器内的混合液悬浮物(MLSS)质量浓度和胞外多糖与蛋白质的质量比较高,但污泥体积指数却较低;加Fe³⁺反应器内的胞外多聚物含量在驯化前期高于对照样,在驯化后期却低于对照样;加Fe³⁺可以提高污泥的沉降性能和絮凝性能。     

CdTe为荧光探针测定罗汉参中的混合氨基酸

制备一种新型量子点CdTe,建立一种以CdTe为荧光探针测定罗汉参中混合氨基酸的方法。向荧光量子点CdTe溶液中加入Co2+后其荧光强度降低,降低的程度在一定范围内与Co2+浓度成线性关系;加入氨基酸后,荧光强度又得到恢复,而量子点荧光的恢复强度与加入氨基酸的浓度呈线性关系。在混合氨基酸标准溶液2.0×10-8~5.5×10-7mol/L线性范围内,量子点荧光的恢复强度与混合氨基酸浓度的线性方程为y=1.04×106x+1.013,相关系数R2=0.9995。考察了不同缓冲溶液、pH、Co2+浓度等因素对体系造成的影响。结果表明,在pH=9.5的硼砂缓冲溶液中,2.0×10-5mol/L的Co2+能很好的猝灭CdTe荧光。应用于实际样品测定的相对标准偏差(n=5)为3.0%,加标回收率在98.3%~104.4%范围内,检出限为1.1×10-8mol/L。该方法简单、快速,实用性强。     

高荧光CdTe量子点荧光探针测定Cu~(2+)

以亚碲酸钠为碲源,巯基丙酸(MPA)和柠檬酸三钠为稳定剂在水相中一步合成了具有良好荧光性质的Cd Te量子点,并利用Cd Te量子点与Cu2+混合后会发生荧光猝灭的现象,建立Cu2+测定方法,并对反应条件如缓冲体系的浓度和p H值、反应时间、量子点浓度以及试剂添加顺序进行优化。优化结果为:在p H 6.6、浓度为0.01 mol/L的磷酸一氢钠—磷酸氢二钠缓冲液中,量子点浓度5×109mol/L,以量子点—缓冲液—金属离子的添加顺序反应30 min,可得到最佳反应效果。研究显示,最佳试验条件下,Cu2+浓度为0~5×107mol/L范围内,Cd Te量子点的荧光强度猝灭程度与Cu2+浓度之间呈良好的线性关系,线性相关系数R2=0.988 4,检出限为1×108mol/L。     

基于Fe3O4@C/\[BSMIM\]HSO4/GCE传感器检测铅离子

目的：采用Fe₃O₄@C/\[BSMIM\]HSO₄/GCE对水中的铅离子进行定量分析。方法：在四氧化三铁（Fe₃O₄）的基础上,制备了具有核壳结构的Fe₃O₄@C纳米复合材料,并复合1-甲基-3-丁磺酸基咪唑硫酸氢盐 （\[BSMIM\]HSO₄）离子液体,以玻碳电极（Glassy carbon electrode,GCE）为载体,制备了Fe₃O₄@C/\[BSMIM\]HSO₄/GCE,并利用其对饮用水中铅离子进行定量分析。结果：Fe₃O₄@C具有良好的导电性和分散性,Fe₃O₄@C/\[BSMIM\]HSO₄/GCE具有较好的电化学稳定性和电催化活性。利用Fe₃O₄@C/\[BSMIM\]HSO₄/GCE对饮用水中铅离子进行定量分析,铅离子浓度与峰电流在0.1～80.0 μg/L内呈良好的线性关系,R²=0.999 5,检出限为0.038 μg/L （S/N=3）,检出限较低,其加标回收率在97.60%～100.93%,回收效果较好,准确度较高。且该传感器重复性较好,连续差分脉冲扫描10次其相对标准偏差为2.446%。结论：该方法简单、快捷、可靠,为饮用水中铅离子的检测分析提供了一种新的解决方案。     

Synthesis of Fe3+-doped Aminated Lignin as A Peroxidase Mimic for Colorimetric Detection of H2O2 and Glucose

Peroxidase plays an important role in living systems; however, its storage difficulty and easy inactivation have limited its applications in complex environments. To address these problems, herein, we proposed a method to synthesize peroxidase mimics by amination, carbonization, and Fe³⁺-doping of industrial alkali lignin. The Fe³⁺-doped lignin-based peroxidase mimic (Fe-LPM), with active centers of coordination between Fe³⁺ and N atoms, showed higher tolerance to pH value and temperature than natural peroxidase. Using Fe-LPM, 10-100 mmol/L of H₂O₂ and glucose could be colorimetrically detected with the lowest detection limits of 80 μmol/L and 1.5 mmol/L and visual detection limits of 1.0 mmol/L and 10 mmol/L, respectively. The Fe-LPM maintained peroxidase-like activity after 10 cycles and could even be used for H₂O₂ detection in practical samples. This work not only provides a new approach to synthesize peroxidase mimics using biomass materials but also promotes the high-value utilization of lignin.     

聚缬氨酸修饰电极法测定食品中2, 6-二叔丁基对甲苯酚的方法研究

目的 建立一种快速、灵敏地测定食品中2, 6-二叔丁基对甲苯酚的新方法。方法 通过探讨聚缬氨酸修饰电极的制备条件,确定了采用循环伏安法制备聚缬氨酸修饰电极的最优聚合条件,研究了2,6-二叔丁基对甲苯酚在此电极上的电化学行为。试验从测定pH、电位、扫描速率等方面进一步探讨了测定2,6-二叔丁基对甲苯酚最佳条件。在最优条件下找出了氧化峰电流与浓度的线性关系,作为工作曲线,进一步对食品中的2,6-二叔丁基对甲苯酚进行了测定。结果 在pH=4.0的磷酸盐缓冲溶液中,2,6-二叔丁基对甲苯酚的氧化峰电流与其浓度在4.0×10_^-7～4.0×10_^-5mol/L范围内呈线性关系,线性方程：ipa=1.27×10-7+0.23c(mol/L),相关系数为0.9962,检出限4.0×10_^-8mol/L。结论 方法简单、快速、灵敏,已运用在食品中2, 6-二叔丁基对甲苯酚的检测,获得了满意的结果。此研究建立了测定食品中2,6-二叔丁基对甲苯酚的新方法。     

基于QuEChERS-高效液相色谱法测定油炸食品中丙烯酰胺含量

目的：简化油炸食品中丙烯酰胺含量检测的前处理过程及对昂贵检测仪器的依赖。方法：使用C₁₈和Z-Sep⁺作为净化材料，甲醇作为提取溶剂，采用C₁₈色谱柱进行分离，以甲醇—水为流动相进行等度洗脱，于197 nm下进行检测。结果：试验方法的丙烯酰胺含量在0.1～2.0 mg/L范围内具有良好的线性关系（R²>0.999），检出限为0.007 mg/kg，对质控样品进行6次平行测定，相对标准偏差为0.66%，对丙烯酰胺进行0.2，0.5，1.0 mg/L 3个水平的加标试验，回收率为91.5%～94.4%，RSD为0.62%～1.88%，日内精密度为1.00%，日间精密度为0.14%。结论：该方法前处理操作简单，对仪器要求低，可以满足传统油炸小吃中丙烯酰胺含量的分析。     

纤维素纳米晶荧光探针的制备及其对Fe3+荧光传感检测

将纤维素纳米晶（CNC）与N-（4-氨基苯基）-4-（N,N-二甲基乙二胺基）-1,8-萘酰亚胺（EADANI）进行共价键结合,制备得到纤维素纳米晶荧光探针（FCNC）,并应用于Fe³⁺的荧光传感检测。结果表明,由于表面羧基和羟基的存在,FCNC具有较好的水分散性,在水溶液中呈现良好的黄色荧光发射性能;Fe³⁺对FCNC具有荧光增强效果,荧光增强因子达9.5,同时在竞争性离子存在情况下,FCNC表现出良好的选择性。     

Adsorption of Cu2+ by Crosslinked Graft Copolymers of Starch

With the use of acrylic acid(AA)as a monomer,humic acid(HA)and starch as raw materials,potassium persulfate(KPS)as initiator,and N,Ndimethylacrylamide(MBA)as a cross-linking agent,AA/HA/Starch graft copolymer was prepared and characterized by SEM and FT-IR.The effects of temperature,adsorption time,adsorbent dosage,pH value and Cu²⁺initial concentration of the solution on the adsorption performance of the crosslinked graft copolymer were also investigated.The results showed that the Cu²⁺adsorption capacity of the AA/HA/Starch graft copolymer increased firstly and then decreased with increasing adsorbent dosage and the initial pH value of Cu²⁺solution.With the increase of Cu²⁺initial concentration and the extension of adsorption time,the adsorption amount of Cu²⁺increased rapidly and then stabilized.And it decreased slightly with the increase of temperature.At pH value of 5.5,temperature of 298 K,adsorbent dosage of 50 mg,adsorption time of 125 min,and 100 mL Cu²⁺solution with Cu²⁺initial concentration of 100 mg/L,the Cu²⁺adsorption capacity of the crosslinked graft copolymer was 238 mg/g.The adsorption of Cu²⁺by the adsorbent followed the pseudo-second-order kinetic equation and Langmuir isothermal adsorption model,and the adsorption was attached to monolayer chemical adsorption.This study proved that AA/HA/Starch graft copolymer could be used as an efficient adsorbent for the removal of harmful and toxic metal cations such as Cu²⁺from industrial wastewater.     

OCC造纸废水中微细胶黏物及Ca2+协同去除的研究

废旧箱纸板（OCC）造纸废水回用过程中面临着微细胶黏物沉积和因Ca²⁺浓度过高引起的厌氧颗粒污泥钙化两大难题。本研究对比评估了电絮凝法、物理法、化学法、生物酶法对模拟OCC造纸废水的处理效果;结果表明,电絮凝法能够更好去除OCC造纸废水中的微细胶黏物和Ca²⁺。在此基础上研究了电絮凝处理的最佳条件：铝为阳极材料,电流密度、电极间距和反应时间的最佳处理条件分别为115 A/m²、5 cm和60 min。在最佳条件下,经电絮凝处理后得到的絮凝体中,Al³⁺和Ca²⁺的相对含量高于对照组,表明电絮凝法能有效去除OCC造纸废水中的微细胶黏物、COD和Ca²⁺,且该方法绿色无污染,符合可持续发展的要求。     

吸附Ca2+纳米4A沸石与碳酸钙复配用作造纸填料的研究

纳米4A沸石广泛用于高钙废水的处理,本研究探讨了吸附Ca2+纳米4A沸石与碳酸钙复配加填对纸张性能的影响。结果表明,吸附Ca2+纳米4A沸石与碳酸钙在粒径分布和形貌特征上具有良好的匹配性。吸附Ca2+纳米4A沸石替代量在50%时,纸张的抗张指数较碳酸钙填料提高了7.4%;替代量在25%时,耐破指数提高了4.8%,环压指数提高了21.1%。吸附Ca2+纳米4A沸石表现出与纤维之间明显的交织作用,纸张纤维之间具有更好的结合度,提高了纸张的平滑度。     

不同pH值下 Fe3+对好氧活性污泥处理制浆中段废水的影响

本课题以不加Fe~(3+)的活性污泥作为对照,探讨了在Fe~(3+)存在下,pH值对好氧活性污泥处理制浆中段废水的影响。研究表明,当pH值为6.5时,对照组和添加Fe~(3+)的实验组的CODCr去除率分别达到77%和79%。当超出该pH值范围,对照组和实验组的COD_(Cr)去除效果均下降。Fe~(3+)的存在提高了处理效果,特别是pH值明显偏离正常值,pH值为8.5和9.5时尤为明显。通过对脱氢酶浓度和污泥絮凝性能的研究结果表明,当pH值在5.5~7.5的范围时,两个指标都显示了污泥良好的性能,但在其他pH值条件下,污泥活性和絮凝性能均出现下降。与对照组相比,Fe~(3+)的存在提高了污泥的活性和絮凝性能。     

钙型糖柱—高效液相色谱—蒸发光散射检测器法测定牛乳中的乳糖

目的：实现牛乳中乳糖含量快速检测。方法：建立基于钙型糖柱和高效液相色谱测定牛乳中乳糖的新方法。牛乳通过0.2 g/mL三氯乙酸溶液沉淀蛋白质，所得滤液稀释100倍并过滤膜后进入高效液相色谱系统，经过钙型糖柱分离，蒸发光散射检测器进行检测。结果：乳糖在线性范围（20～100 mg/L）内，色谱峰面积和质量浓度之间具有较好的相关性，R²为0.999 8。乳糖加标水平为15，40，80 mg/g时，回收率为90.96%～98.23%，检出限为3.6 μg/g，定量限为12 μg/g，在6 min内实现乳糖浓度的测定。并且用该方法测定11种市售乳样品，测得结果与国标（GB 5009.8—2016）法基本一致。结论：该方法的精密度、重复性、加标回收率均符合有关规定，检测结果准确且耗时短，适用于快速检测牛乳中的乳糖含量。     

The cytochrome bcc-aa3-type respiratory chain of Rhodococcus rhodochrous

Rhodococcus rhodochrous is an active soil bacterium belonging to the Nocardia group of high GC Gram-positive bacteria. It is rich in various enzymes and thus important in the industrial production of chemicals and bioremediation. In this work, the respiratory chain of this aerobic organism was investigated and characterized. Grown under highly aerobic conditions, the membrane fraction of R. rhodochrous cells only contained a-, b- and c-type cytochromes, suggesting that it is the cytochrome bcc-aa₃-type pathway that mainly operates under these conditions. In contrast, the d-type cytochrome was also present under microaerobic conditions, indicating that the alternative pathway of the bd-type oxidase works in these circumstances. In addition, the results of H⁺/O ratio measurements indicate that these two pathways have different energy efficiencies.     

Enzymatic synthesis of primeverosides using transfer reaction by Trichoderma longibrachiatum xylanase

Enzymatic synthesis of two phenyl xylopyranosyl glucopyranosides, through transfer reaction by Trichoderma longibrachiatum endoxylanase, was achieved in the presence of n-hexane used as solvent, phenyl glucoside (10 mM) as acceptor and xylan (2 g/l) as donor. Kinetic study showed that only one compound, identified by ¹H and ¹³C NMR and heteronuclear 2D (¹H–¹³C) chemical shift correlation as phenyl primeveroside (phenyl 6-O-β-xylopyranosyl-1-β-d-glucopyranoside), was synthesized when the reaction time was beyond 1 h. Benzyl and hexyl primeverosides were obtained under the same conditions. When several phenyl glucoside concentrations, from 5 to 50 mM, were used with 2 g/l of xylan, a phenyl primeveroside isomer, identified as phenyl 4-O-β-xylopyranosyl-β-d-glucopyranoside, accumulated in the medium whereas the production of phenyl primeveroside decreased. Only phenyl primeveroside was produced when several xylan concentrations from 2 to 10 g/l were used with 10 mM of phenyl glucoside and its concentration in the reaction mixture increased with the increase of xylan concentration.