A method of gas chromatography-mass spectrometry (GC-MS) was established to determine the migration of dibutyl sebacate, dioctyl sebacate, diisooctyl sebacate, decanedioic acid bis(2,2,6,6-tetramethyl-4-piperidinyl)ester in water-based, acidic and alcoholic food simulants, and olive oil and chemical alternative solvents. The 95% ethanol and isooctane chemical substitution solutions were directly analyzed by GC-MS. The olive oil samples were extracted with acetonitrile followed by QuEChERS purification, and then analyzed by GC-MS. Other simulants (water, 4% acetic acid, 10% ethanol, 20% ethanol, and 50% ethanol) were extracted with n-hexane and then determined by GC-MS. The results showed that the method is well performed under optimized conditions, with the correlation coefficient (r2) greater than 0.995. The limits of detection and the limits of quantitation of the four sebacic acid ester compounds in water, 4% acetic acid, 10% ethanol, 20% ethanol, 50% ethanol, 95% ethanol, isooctane, and olive oil simulants are 0.1-0.2 mg/kg, 0.3-0.5 mg/kg, respectively. Migration experiments on plastic samples were conducted, and spiking experiments at three concentration levels of 0.30, 2.0, 4.0 mg/kg in water, 4% acetic acid, 10% ethanol, 20% ethanol, 50% ethanol, 95% ethanol, and isooctane food simulants, and three concentration levels of 0.50, 2.0, 4.0 mg/kg in olive oil food simulants were carried out. The spiking recoveries range from 92.5% to 108%, and the relative standard deviations (RSDs) are 2.4%-8.8%. The method solves the problem that decanedioic acid bis(2,2,6,6-tetramethyl-4-piperidinyl)ester cannot be extracted into n-hexane in 4% acetic acid by adjusting pH value using ammonium hydroxide, the optimal pH range was determined by comparing the responses of four targets at different pH values. QuEChERS was firstly used for migration experiments of sebacic acid esters in food contact materials to solve the turbidity and partial oil precipitation of olive oil simulants in the concentration process after extraction. By optimizing the QuEChERS filling material, the interference of organic acids, fatty acids, sugar and other impurities on the targets were reduced, producing greater separation effect of the targets. The separation efficiency of four chromatographic columns with different polarity was compared, and the DB-17HT column was selected to detect the four sebacic acid esters simultaneously. Plastics such as polypropylene, polyethylene terephthalic acid terephthalate, polyvinyl chloride, composite membranes, paper cups, recycled PET and recycled PVC were collected and migration experiments were carried out, the migration of sebacic acid esters in these plastics materials was investigated. This method is highly sensitive, precise, and accurate, fully meeting the requirement for determining the migration of the sebacic acid esters in food contact materials and their products.
The SWSRA-DS combined algorithm is proposed with the goal of sharing the near infrared analysis model of the holocellulose content of pulpwood on three different types of spectroscopic instruments. That is, the screening wavelengths based on spectrum ratio analysis (SWSRA) algorithm is used to select the wavelengths with good stability and consistency. These important wavelength variables, which are insensitive to the measured sample parameters, can reduce the differences in sample information response by different instruments or measurement conditions. Then the systematic errors that still existed after the SWSRA method calibration are further calibrated using the Direct Standardization (DS) method on the basis of these wavelengths. This combined algorithm can improve the generalizability of the master model, reduce the spectrum matrix dimension, and make the model transfer more stabilized and simple. The results show that the SWSRA-DS combined algorithm is able to reduce the RMSEP of the master model to predict the holocellulose content of samples measured on the target 1 and target 2 instruments from 2.01% and 9.45% to 0.96% and 1.08%, respectively. The SWSRA-DS algorithm result is compared with the calibration results of SWSRA and DS alone and the commonly used PDS and S/B model transfer algorithms to transfer performance is significantly improved, which provides a new idea for the sharing of NIR analysis models among different types of spectroscopic instruments.
The magnetic solid phase extraction material (MnFe 2 O 4 @TiO 2 ) was prepared by coating TiO 2 on MnFe 2 O 4 through an in-situ formation method. The structure and properties of MnFe 2 O 4 @TiO 2 were characterized by Xray diffractometer (XRD), scanning electron microscope (SEM), nitrogen adsorption -desorption experiment, and vibrating sample magnetometer (VSM). The conditions for magnetic solid phase extraction (MSPE) of quinolone antibiotics were optimized, and an MSPE-HPLC method was established to determine quinolone antibiotics in water samples. The optimal conditions for MSPE are MnFe 2 O 4 @TiO 2 amount of 15 mg, extraction time of 15 min, 5 mL of methanol solution with 20 % ammonia as eluent, and elution time of 1 min. Under the optimal conditions, 50 mL 0.1 mg/L mixed standard solutions of fleroxacin, ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin have achieved enrichment multiples of 67.8, 72.1, 59.6, 55.8, and 60.7, respectively. The linear range of five antibiotics determined by MSPE-HPLC is 0.004 -1 mg/L with the relative standard deviations (RSDs) of 2.1 % -4.9 % and the limits of detection (LODs) of 0.0006 -0.0020 mg/L. The method is applied to the determination of the five antibiotics in rice paddy water and fish pond water; the recoveries range from 78.9 to 105.8 %, and the RSDs (n = 5) are 3.6 % -8.7 %.
A new compound, 5-methyl-2-phenyl-1,2,3-triazole-5-hydrazid (PT) was designed and synthesized based on "click chemistry". The fluorescence probe 5-methyl-2-phenyl-1,2,3-triazole-5-hydrazid Schiff base (PTSB) was further constructed by a chemical reaction between PT and 4-(diethylamino) salicylaldehyde. PTSB could be used to determine Al3+ in EtOH with high sensitivity and strong anti-interference performance by fluorescence and UV-vis spectroscopic methods. The limit of detection to Al3+ is 5.84 nM and it showed an obvious sol-vatochromic effect under ultraviolet light. Furthermore, the sensing mechanism of PTSB detecting Al3+ was confirmed in the form of planar structure and 1:1 complexation ratio based on MS, Job's plot, 1H NMR titration, DFT calculation, and the single-crystal structure of PTSB, respectively. PTSB showed less low cytotoxicity to HeLa cells and was successfully used for chromatic bioimaging Al3+ in HeLa cells. It is expected to be developed and utilized as a fluorescence probe for detecting Al3+ in vivo.
A novel fluorescent molecule TPE-SA with aggregation-induced emission(AIE)properties was designed and synthesized based on the structure of tetraphenyl ethylene(TPE).The fluorescent molecule had favorable optical performance,a large Stokes shift and high fluorescent efficiency,and is capable of being employed as a fluorescent probe for the selective detection of Cu2+ based on the phenomena that its fluorescence intensity in the solution(VDMSO:VH2O=5:95)decreased after addition of Cu2+.The detection range was 0.05-8 μmol/L,and the limit of detection was 25 nmol/L.The probe can be applied for measuring Cu2+ in lake samples.
基于Hg 2+ 对明胶-金纳米粒子（G-AuNPs）类过氧化物酶活性的增强作用，构筑了一种新型的Hg 2+ 传感器。所制备G-AuNPs 具有类氧化物酶活性和类过氧化物酶活性，表现为能够催化O 2 或H 2 O 2 氧化3，3，5，5’-四甲基联苯胺（TMB）生成氧化TMB（oxTMB）的反应，在652 nm处出现紫外可见吸收特征峰。对影响类过氧化物酶活性的实验参数进行优化，获得最佳反应条件。通过稳态动力学研究获得米氏常数K m 分别为 0.70 mmol/L(H 2 O 2 为底物)和0.78 mmol/L（TMB为底物）。Hg 2+ 能够增强G-AuNPs的类过氧化物酶活性，使吸收信号升高，且升高幅度与Hg 2+ 浓度呈线性关系，在0～15 μmol/L和15～35 μmol/L范围内的线性方程分别为y=1.314+0.0135x和y=0.704+0.055x，检出限为1.65 μmol/L。该传感体系对Hg 2+ 具有良好的选择性，其它常见金属离子不干扰对Hg 2+ 的检测。所设计传感器具有无需修饰、检测时间短、选择性好的优点，有望用于现场污染水中Hg 2+ 的检测。
The oxidase-like activity of cobalt oxyhydroxide（CoOOH） nanosheets is inhibited by arsenic（Ⅴ） in the system, thereby attenuating the oxidation of p-phenylenediamine（PPD） by CoOOH nanosheets, and changing the absorbance of the solution. Based on this principle, and the fluorescence inner filter effect（IFE） of p-phenylenediamine oxide（oxPPD） on the dye acridine orange（AO）, a colorimetric and fluorescence dualmode method for the quantitative detection of As（Ⅴ） was established. The variation of absorbance and fluorescence intensity of As（Ⅴ） with different concentrations was investigated, and the effects of the concentrations of CoOOH nanosheet and PPD, pH of buffer solution, and temperature of reaction were optimized. The results showed that under the optimized conditions, the concentration of As（Ⅴ） had a good linear relationship with the corresponding signal intensity, and the detection limits of colorimetric and fluorescence method were 5 and 10 nmol/L, respectively. The method has been used for the determination of arsenic（Ⅴ） in lake water located the city center.
An ultra-high performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS） method was established for the determination of 67 kinds of hormones in eczema cream. Samples were first dispersed with saturated sodium chloride solution, then the analytes were extracted with ethyl acetate, purified by modified QuEChERS adsorbents, and detected by UPLC-MS/MS. The hormones were separated on Waters AcQuity BEH C18（1.7 μm, 2.1 mm×100 mm）column, and detected with scheduled multi-reaction monitoring（sMRM） in positive and negative mode. As a result, 67 kinds of hormones had good linear relationships in the corresponding concentration ranges with the correlation coefficients greater than 0.995. The average recoveries of 67 kinds of hormones at three spiked levels ranged from 71.8% to 115.9%, with the relative standard deviations（RSDs） of 1.7%-12.5%. The limits of quantification（LOQs） were 0.15-1.00 μg/kg. This established method can meet the actual testing needs of 67 kinds of hormones in eczema cream samples.
建立了一种超高效液相色谱-串联质谱法测定化妆品中61种性激素的方法。水基类、乳液类、膏霜类和凝胶类化妆品经乙腈分散，50%（V/V）乙腈水溶液超声提取，油基类样品经正己烷分散，70%（V/V）乙腈水溶液涡旋提取，采用CORTECS C 18 （2.1 mm×150mm，2.7 μm）色谱柱进行分离，选择乙腈、水为流动相进行梯度洗脱，多反应监测（MRM）模式检测，基质外标法定量。结果表明，61种性激素的检出限和定量限分别为0.03 ～ 0.31 μg/g和0.09 ～ 0.92 μg/g，在15 ～ 150 μg/L范围内线性关系良好(相关系数R 2 ＞0.99)。选择了5种化妆品基质，在低、中、高3个加标水平下，61种性激素的加标回收率为80.0% ～ 117.7%，相对标准偏差（RSD） 为1.5% ～14%。该方法可以为化妆品的快速风险筛查和国家标准的制修订提供技术支撑。
基于Cu2+与双环己酮草酰二腙(BCO)的显色体系构建比色免疫传感器,并用于癌胚抗原(CEA)定量分析,满足临床检测肿瘤的要求.在磁珠表面通过抗原抗体之间的特异性结合,构建三明治型免疫复合物,通过CuO与抗体的结合实现信号转导.酸性条件下CuO可被分解为Cu2+,Cu2+与BCO在弱碱性条件下发生络合,溶液由无色变为蓝色,且溶液吸光度值与CEA浓度的对数呈线性正相关.最佳条件下,该免疫分析法的线性检测范围为0.1～40ng/mL,检出限为0.02ng/mL.
建立了针筒式分散固相萃取结合超高效液相色谱串联质谱法同时测定畜禽源有机肥中10种大环内酯类药物的分析方法.样品经甲醇和乙腈提取后,提取液通过预先装填有60 mg PSA和30 mgC18的注射器进行针筒内分散固相萃取净化后,经BEHC18色谱柱分离,在电喷雾正离子模式下以多反应监测方式检测,基质匹配外标法定量.结果表明,在低、中、高(10,30,50 μg/kg)3种加标水平下,目标物的回收率在70％～110％之间,相对标准偏差为1.4％～12％.方法检出限和定量分别为0.57～1.75 μg/kg和2.77～5.40 μg/kg.该方法适用于有机肥中大环内酯类药物多残留的同时快速测定.
以苏丹红Ⅲ核酸适配体为识别元件,以无标记的纳米金为颜色指示剂,NaCl溶液作为纳米金聚集诱导剂,构建了一种简单、快速、灵敏的苏丹红可视化比色检测方法.对适配体浓度、NaCl浓度、反应时间等条件进行优化,并对该方法的灵敏度、准确性、特异性进行评估,将其应用于食品中苏丹红Ⅲ的快速检测,并与国标法对比验证.结果显示,在适配体浓度100nmol/L、NaCl浓度40 mmol/L、反应时间10min等最优条件下,纳米金吸光度比值(A620/A520)与苏丹红浓度在1.8～57.6ng/mL范围内呈良好线性关系(R2=0.981),方法检出限范围0.76～1.12ng/mL,裸眼可视化检出限为7.2ng/mL,检测时间为12min.特异性分析显示,本方法对苏丹红Ⅰ,Ⅱ和Ⅳ有交叉反应,表明可以用于检测苏丹红Ⅰ～Ⅳ.食品中苏丹红Ⅲ加标回收率为82.1％～94.7％,相对标准偏差3.9％～7.7％,与国标方法相比无显著差异(P＞0.05).该方法适用于批量样品中苏丹红的快速检测.
建立了一种以多壁碳纳米管(MWCNTs)为吸附剂的QuEChERS-气质联用法(GC-MS/MS)测定金银花中72种农药残留的分析方法.样品采用美国官方农业化学家协会(AOAC)提取包提取,MWCNTs改良的净化管净化,动态多反应监测模式(dMRM)分析,基质匹配标准曲线外标法定量.结果表明,72种农药在各自线性范围内呈良好的线性关系,相关系数均大于0.9936,检出限在0.001～0.178 μg/kg之间,定量限在0.002～0.593 μg/kg之间,4个添加水平的回收率为60.1％～118.0％,相对标准偏差(RSD)为2.2％～17％.
以禾本科植物大麦的幼苗为原料,建立了基于制备型高速逆流色谱技术的大麦黄苷和皂草黄苷标准样品的规模化快速制备工艺,从200 g大麦幼苗中制得1.2 g大麦黄苷和1.6 g皂草黄苷.经HPLC和HPLC/MS分析,纯度均大于99％,无明显杂质峰;经1H-NMR和13C-NMR确定其结构为大麦黄苷和皂草黄苷.该样品在95％置信区间均匀性良好,4℃条件下24个月内稳定性良好,定值结果确定其纯度分别为99.59％和99.52％,相对扩展不确定度(包含因子k=2)分别为0.52％和0.50％.
采用超高效液相色谱-串联质谱法(HPLC-MS),建立了同时测定猕猴桃中11种植物生长调节剂残留量的方法.样品经酸化乙腈提取后,采用QuEChERS法净化,CortecsT3柱(2.1 mm×100mm,2.7 μm),以含0.1％甲酸的5 mmol/L乙酸铵溶液和甲醇作为流动相进行梯度洗脱,电喷雾电离和多反应监测模式进行检测,基质匹配外标法定量.结果表明,11种植物生长调节剂线性关系良好,相关系数均大于0.998,平均回收率在80.5％～107.3％之间,相对标准偏差在2.3％～8.2％之间.
建立了高效液相色谱法(HPLC)测定血浆中氯解磷定(PAM)的含量,研究了不同给药方式对大鼠体内药代动力学行为的影响.优化条件为:色谱柱CAPCELL PAKC18 MGIII(250mm×4.6mm,5 μm),以5 mmol/L正庚烷磺酸钠溶液(含体积比0.12％三氟乙酸)-乙腈为流动相进行梯度洗脱,流速1 mL/min,检测波长294 nm,内标双复磷.血浆中PAM浓度在0.5～100 mg/L范围内与PAM和内标峰面积之比具有良好的线性关系,相关系数为0.9996.方法日内精密度分别为7.1％,3.3％,3.6％,日间精密度分别为9.1％,9.7％,7.1％,重复性相对标准偏差(RSD)为0.76％,可用于血浆中PAM的含量测定.药代动力学结果表明,相比静脉注射组,肌内注射组药物半衰期和平均滞留时间延长.肌内注射PAM更适用于急性中、重度有机磷中毒的临床治疗.
以萘酰亚胺衍生物为荧光团,构建了一种同时检测NO和pH的荧光探针Na-pHNO.该探针在99％磷酸盐缓冲溶液(PBS)和1％二甲基亚砜(DMSO)中荧光性质良好,在544 nm处出现荧光发射峰,且随着NO浓度增大或pH减小荧光显著增强.探针Na-pHNO对NO的识别呈现出特异性强、灵敏度高、抗干扰性强等特性;在pH 5.5～8.5范围内,探针具有良好的荧光可逆性.光谱研究表明,该探针因双重光诱导电子转移(PET)效应具有微弱荧光,与NO和pH作用后发生双重PET抑制效应,荧光显著增强.Hela细胞的荧光成像研究表明,该探针能够实现对细胞内pH和NO浓度变化的可视化监测,并已成功应用于秀丽隐杆线虫的荧光成像.
采用改进的QuEchERS前处理方法结合超高效液相色谱串联质谱(UPLC-MS/MS),建立了青贮皇竹草中23种农药残留的检测方法.样品经超纯水浸泡,1％甲酸乙腈提取,无水MgSO4、乙二胺-N-丙基硅烷(PSA)、十八烷基硅烷(C18)和石墨化炭黑(GCB)基质分散净化,Agilent ZORBAX Eclipse Plus C18色谱柱分离,电喷雾串联质谱多反应监测(MRM)模式测定.23种农药在0.5～20μg/L范围内线性关系良好(R2＞0.9986),检出限为0.002～0.1 μg/kg,定量限为0.005～0.2 μg/kg.在0.5,1,5 μg/kg 3个添加浓度水平下,回收率在76.2％～105.9％,相对标准偏差(RSD)在2.3％～11％.该方法适用于青贮皇竹草中23种农药的定性定量分析.
通过高温共沉淀法制备了发光效率高、形貌规则、粒径均一的上转换纳米粒子;采用反相微乳法合成二氧化硅壳层(SiO2),实现上转换纳米粒子从油相到水相的转移;将介孔二氧化硅壳层(mSiO2)包覆在上转换纳米粒子表面,荧光响应分子姜黄素被负载在mSiO2的孔道中.基于荧光共振能量转移的原理,构建"Turn on"纳米传感体系,并用于Cu2+的检测,检测线性范围为10～50μmol/L,检出限为0.5 μmol/L.本方法可实现大鼠血清样品中Cu2+的检测.
中心蛋白(centrin)通过构象变化吸引多种修复因子到DNA损伤位点,参与核苷酸切除修复的识别过程,利用荧光探针可以研究蛋白质的构象变化.本研究以2-对甲苯胺基-6-萘磺酸(TNS)为探针,应用光谱法探究了八肋游仆虫中心蛋白N-端半分子(N-EoCen)与小牛胸腺DNA(CT-DNA)作用后的构象变化.结果表明,N-EoCen可以与CT-DNA形成复合物,复合物的形成使得蛋白的构象发生变化,疏水腔暴露.Ca2+与N-EoCen配位后,有利于N-EoCen与CT-DNA的结合,会进一步诱导蛋白中疏水性氨基酸残基的暴露.本文研究结果为今后研究中心蛋白在核苷酸切除修复的识别过程中的分子机制提供了理论基础,并且为TNS作为探针应用于检测蛋白质与其他生物大分子的作用提供了参考.
