基于遗传算法的波长选择方法在绿茶近红外光谱分析模型中的应用

利用遗传算法(GA)提取茶叶的近红外吸收特征波长的方法,研究建立了绿茶水分和氨基酸的近红外分析模型,并对波长选择前后两种成分的模型进行了比较分析。结果表明,经遗传算法波长选择后,简化了分析模型,同时模型的稳健性增强。氨基酸预测集的均方根误差(SEP)减小82.1%,水分预测集的均方根误差减小(SEP)76.6%,它们在波长选择前后对应的分析波长数之比分别为995∶7和1990∶33。     

高效毛细管电泳电导法快速检测复方维生素B片中的VB1、VB12、VB6和VC

采用高效毛细管电泳电导法同时分离、测定了复方维生素B片中的主要成分VB1, VB12,VB6和VC的含量.研究了运行缓冲溶液的酸度和浓度、电泳电压、进样时间等因素对电泳的影响.在优化的实验条件下40 mmol/L Tris -4 mmol/L H3BO3 (pH 8.0) 的缓冲溶液中加入0.30 mmol/L CTAB(溴化十六烷基三甲基铵),分离电压为15 kV,上述4组分在5 min内得到良好的分离.维生素B1,B12,B6和VC的线性范围分别为5.5～1.0 mg/mL; 15～1.5 mg/mL; 1.0～0.40 mg/mL和6.6～0.80 mg/mL; 检测限分别为0.80 μg/mL, 4.0 μg/mL, 0.50 μg/mL, 2.9 μg/mL; 5次测定峰高的相对标准偏差分别为2.2%, 1.6%, 3.9%, 2.8%.5次测定的平均回收率分别为99%, 94%, 100%, 97%.     

毛细管电泳柱后衍生激光诱导荧光测定动物组织中卡那霉素类抗生素

采用毛细管电泳柱后衍生激光诱导荧光测定3种卡那霉素类抗生素。研究了在反向电渗流条件下HAc-NaAc缓冲液酸度和浓度对卡那霉素类抗生素分离的影响,研究了Na2B4O7缓冲体系和柱后衍生试剂萘二醛/2-巯基乙醇浓度对检测信号的影响。采用50 mmol/L HAc-NaAc(pH5.0) 0.5 mmol/L CTMAB溶液为分离缓冲液,样品在-15 kV下分离,与柱后衍生试剂1.0 mmol/L NDA 8.0 mmol/L 2-ME 35 mmol/LNa2B4O7(pH10.0)的30%(V/V)甲醇溶液反应,激发诱导荧光检测卡那霉素类抗生素检出限为3.6×10-5~5.2×10-5g/L;本方法用于动物组织中卡那霉素类抗生素残留检测,相对标准偏差小于7.2%;回收率为90.2%~95.3%(n=4)。     

毛细管电泳/发光二极管诱导荧光法测定麻黄中麻黄碱与伪麻黄碱含量

基于麻黄碱及伪麻黄碱衍生物的光谱及化学性质,设计并构建了毛细管电泳/发光二极管诱导荧光检测系统.对关键光学元件进行组合选择,以蓝光发光二极管为光源,BP 470和BP 530分别为光源滤光片和荧光滤光片,光电倍增管检测信号,并对电泳分离系统的缓冲溶液、分离电压等参数进行优化;以FITC为衍生试剂,10 mmol/L Na2B4O7+ 16 mmol/L SDS为缓冲溶液,12 kV电压下可实现麻黄中麻黄碱和伪麻黄碱的基线分离.在0.25～10 mg/L范围内,麻黄碱和伪麻黄碱标准溶液的质量浓度与荧光响应的峰高之间呈较好的线性关系,相关系数(r)均大于0.99,其检出限分别为0.38 μg/L和0.29 μg/L,峰高的日内重复性(RSD)分别为2.0％和2.2％,日间重复性(RSD)分别为5.4％和5.1％.将该方法用于中药麻黄中麻黄碱和伪麻黄碱的测定,加标回收率分别为94％和107％.     

毛细管电泳电致化学发光法同时测定氯丙嗪、异丙嗪及其主要代谢物

建立了同时检测氯丙嗪、异丙嗪及其主要代谢物的毛细管电泳电致化学发光新方法。最佳实验条件为: 检测电位1.20 V,钌联吡啶浓度5 mmol/L,检测池磷酸缓冲溶液40 mmol/L (pH 6.5),分离磷酸缓冲溶液18 mmol/L (pH 4.8),进样电压11 kV,进样时间8 s,分离电压13.5 kV。方法的检出限(3σ)分别为氯丙嗪8.3×10~7 g/L、异丙嗪7.2×10~6 g/L、氯丙嗪亚砜1.9×10~5g/L和异丙嗪亚砜3.7×10~6g/L,各组分的电化学发光强度和迁移时间的相对标准偏差(RSD)分别不超过3%和1%。本方法具有简便、快速、灵敏、进样量少和不受共存物干扰等特点,可在不必预分离的情况下直接同时连续测定家犬尿样中的氯丙嗪、异丙嗪、氯丙嗪亚砜和异丙嗪亚砜。     

交联酚醛型咪唑啉树脂的合成与吸附性能研究

以苯酚及一氯醋酸为原料,合成了新型交联酚醛咪唑啉树脂.合成树脂对Au3 、Pt2 、Cu2 、Ag 、Hg2 、Co2 、Ni2 具有良好的吸附性能,其静态吸附容量分别为2.278mmol/g,1.530mmol/g,2.692mmol/g,2.390mmol/g,1.901mmol/g,1.644mmol/g,1.488mmol/g(25℃).吸附Cu2 、Hg2 、Ag 、Co2 的表观速率常数(k/min)分别为3.2659×10-2,1.7124×10-2,1.9611×10-2,2.8175×10-2.吸附Cu2 ,Ni2 ,Co2 和Ag 的最佳pH值分别为6.0～6.5,6.0～6.5,6.0～6.5和5.5～6.0.     

直接竞争酶联免疫吸附法测定饲料中沙丁胺醇

应用本实验室制备的对沙丁胺醇(SAL)具有高亲和力的多克隆抗体和酶标半抗原,采用包被抗体-酶标半抗原直接竞争模式建立沙丁胺醇的酶联免疫吸附分析(ELISA)法。在优化实验条件下,ELISA法检测沙丁胺醇的线性浓度范围为0.1~1.0×10~3μg/L,沙丁胺醇对抗体-酶标半抗原结合反应的抑制中浓度(Ic50)为14μg/L,相对标准偏差(RSD)为8.6%(n=5),定量检测下限(Ic_(10))为0.29μg/L。在猪饲料中分别添加沙丁胺醇标样10、50、250μg/kg,ELISA法检测的回收率分别为85%~108%、81%~92%和81%~102%,RSD(n=5)分别为9.1%、5.6%和8.9%,对饲料中沙丁胺醇的最低定量检测浓度为4.23μg/kg。利用高效液相色谱-紫外检测(HPLC-UV)法同步测定饲料中添加250μg/kg沙丁胺醇的平均回收率为89%(n=3),相对标准偏差为3.9%。     

毛细管电泳高频电导法测定粉防己药材中的生物碱

建立了千金藤属植物粉防己中生物碱测定的毛细管电泳高频电导法,以融硅毛细管(150μm×60cm)为分离柱,1mmol LHAc 2mmol LNH4Ac 10mmol Lβ CD 2mmol LSDS缓冲液为电泳介质,分离电压14.0kV,用高频电导法检测,粉防己药材中粉防己碱和去甲粉防己碱可实现定量分离和检测。探讨了缓冲液的种类、浓度、添加剂、分离电压和进样量对分离和检测的影响;在优化条件下的线性范围分别为:粉防己碱12 5～900μg mL,去甲粉防己碱25 0～900μg mL;检出限分别为:粉防己碱6 25μg mL,去甲粉防己碱12.5μg mL;样品加标回收率分别为92.7%～98.9%和95.9%～101%。     

离子色谱法测定饱和卤水中痕量碘离子

建立了一种在线样品预处理、脉冲安培检测饱和卤水中痕量I-的离子色谱新方法。进样体积为50μL,选用Cryptand C1浓缩柱富集I-,并用10 mmol/L NaOH洗脱样品中的基体Cl-。用0.5 mmol/L NaOH将I-从浓缩柱转移到保护柱柱端。用IonPac AS20阴离子交换柱,25 mmol/L NaOH淋洗分离,结合脉冲安培银工作电极检测。I-检出限为0.07μg/L(3倍基线噪音);I-在5~1000μg/L范围内具有良好的线性关系(r=0.9995)。50μg/L的I-溶液连续进样9次,峰高相对标准偏差(RSD)为1.0%。     

在线样品浓缩毛细管区带电泳分析毛发中的苯丙胺类毒品

建立了毛细管区带电泳(CZE)的在线场放大样品堆积(FASS)方法。采用含有40%乙烯乙二醇的100 mmol/L磷酸盐二元缓冲液(pH 2.5),80%异丙醇的0.1 mmol/L磷酸样品溶液,利用缓冲体系与样品溶液体系电导率的差异,在毛细管中浓缩样品组分,对苯丙胺、甲基苯丙胺、亚甲基二氧基苯丙胺(MDA)、亚甲基二氧基甲基苯丙胺(MDMA)4种毒品进行了分离和定量测定,检测的灵敏度提高约1000倍。对于标准品的检出限可达到0.06μg/L。当样品浓度高于5μg/L时,分析的相对标准偏差在10%范围之内;用该方法对添加毒品的毛发进行了提取和测定,可检测到的添加浓度为1μg/g毛发。该方法可用于生物检材中苯丙胺类毒品的检测。     

Valorization of Fermented Shrimp Waste with Supercritical CO2 Conditions: Extraction of Astaxanthin and Effect of Simulated Gastrointestinal Digestion on Its Antioxidant Capacity

Lactic acid fermentation increases the bioactive properties of shrimp waste. Astaxanthin is the principal carotenoid present in shrimp waste, which can be found esterified in the liquid fraction (liquor) after its lactic acid fermentation. Supercritical CO₂ technology has been proposed as a green alternative to obtain astaxanthin from fermented shrimp waste. This study aimed to optimize astaxanthin extraction by supercritical CO₂ technology from fermented liquor of shrimp waste and study bioaccessibility using simulated gastrointestinal digestion (GD) of the optimized extract. A Box–Behnken design with three variables (pressure, temperature, and flow rate) was used to optimize the supercritical CO₂ extraction. The optimized CO₂ extract was obtained at 300 bar, 60 °C, and 6 mL/min, and the estimated characteristics showed a predictive extraction yield of 11.17%, antioxidant capacity of 1.965 mmol of Trolox equivalent (TE)/g, and astaxanthin concentration of 0.6353 µg/g. The experiment with optimal conditions performed to validate the predicted values showed an extraction yield of 12.62%, an antioxidant capacity of 1.784 mmol TE/g, and an astaxanthin concentration of 0.52 µg/g. The astaxanthin concentration decreased, and the antioxidant capacity of the optimized extract increased during gastrointestinal digestion. In conclusion, our optimized supercritical CO₂ process is suitable for obtaining astaxanthin from shrimp by-products after lactic acid fermentation.     

Non-invasive determination of ethanol, propylene glycol and water in a multi-component pharmaceutical oral liquid by direct measurement through amber plastic bottles using Fourier transform near-infrared spectroscopy

Fourier transform near-infrared (FT-NIR) spectroscopy was used to quantify rapidly the ethanol (34-49% v/v), propylene glycol (20-35% v/v) and water (11-20% m/m) contents within a multi-component pharmaceutical oral liquid by measurement directly through the amber plastic bottle packaging. Spectra were collected in the range 7302-12,000 cm-1 and calibration models set-up using partial least-squares regression (PLSR) and multiple linear regression. Reference values for the three components were measured using capillary gas chromatography (ethanol and propylene glycol) and Karl Fischer (water) assay procedures. The calibration and test sets consisted of production as well as laboratory batches that were made to extend the concentration ranges beyond the natural production variation. The PLSR models developed gave standard errors of prediction (SEP) of 1.1% v/v for ethanol, 0.9% v/v for propylene glycol and 0.3% m/m for water. For each component the calibration model was validated in terms of: linearity, repeatability, intermediate precision and robustness. All the methods produced statistically favourable outcomes. Ten production batches independent of the calibration and test sets were also challenged against the PLSR models, giving SEP values of 1.3% v/v (ethanol), 1.0% v/v (propylene glycol) and 0.2% m/m (water). NIR transmission spectroscopy allowed all three liquid constituents to be non-invasively measured in under 1 min.     

在国产近红外光谱仪实验样机上用偏最小二乘法定量分析大麦成分

采用偏最小二乘法和国产近红外光谱分析仪实验样机，对大麦中的蛋白质和淀粉含量进行了定量测定．测定结果为：对蛋白质和淀粉预测的相关系数分别为０．９６１、０．９４９，相对标准偏差分别为２．７％、２．９％，相对误差分别小于５．７％、６．８％．     

基于非对称场流分离技术分离表征小米淀粉

基于非对称场流分离技术耦合多角度激光光散射检测器和示差折光检测器,建立了分离表征小米淀粉的方法。研究了进样量、交叉流流速、半衰期（t_1/2）、载液离子强度和pH值对小米淀粉分离效果的影响;考察了该方法的重现性;探究了小米淀粉分子结构。结果表明,在进样体积为50 μL、进样质量浓度为0.50 g/L、交叉流流速为1.2 mL/min、t_1/2=3 min、载液为10 mmol/L pH 7.00 NaNO₃（含3 mmol/L NaN₃）的条件下,小米淀粉分离效果最佳。该方法具有良好的重现性,得到的小米淀粉的回转半径相对标准偏差为3.4%、摩尔质量相对标准偏差为7.0%。     

超高效液相色谱串联质谱法测定婴儿奶粉中的维生素B_(12)

建立了超高效液相色谱串联质谱法测定婴儿奶粉中维生素B12的方法。采用三氯乙酸沉淀蛋白质,HLB固相小柱吸附净化提取液中的维生素B12,以50%的甲醇洗脱,吹去甲醇后定容测定,色谱柱为ACQUTITY UPLC BEH C18柱,以甲醇–10 mmol/L乙酸铵水溶液为流动相梯度洗脱,MRM模式,定量离子为m/z 678.3/147.2。在优化条件下,线性范围为0.5~200μg/L,相关系数(r)为0.999 3,检出限为0.3μg/kg,回收率为88.3%~92.9%,测定结果的相对标准偏差小于5%(n=6)。方法具有样品处理简单、灵敏度高、重现性好、分析时间短等优点,可以作为实验室常规测定婴幼儿奶粉中维生素B12的方法。     

近红外光谱法快速分析有机肥料中有机质、总养分和pH值

建立了近红外光谱法结合偏最小二乘(PLS)法测定126种有机肥料中有机质、总养分和p H值的快速方法。采用K–S法分类,选取S–G平滑、S–G导数、多元散射校正和均值平均化4种前处理方法对粉碎后样品的近红外光谱信息进行预处理,以PLS法建立定量分析模型。结果表明,有机肥料中总养分的RC,SEC,RP,SEP,RPD分别为0.990,1.272%,0.985,1.084%,5.9;p H值的RC,SEC,RP,SEP,RPD分别为0.910,0.344%,0.737,0.428%,2.9。有机质项目根据国标方法分为小于40%、小于55%和大于55%3种样品进行分析,3种样品的RP分别为1.000,0.989,1.000;RPD分别为18.9,17.5,8.8。对比国标方法,有机质和总养分的测定精度满足实验室精确分析要求,p H值测定法可用于定量分析。NIR–PLS法实现了对有机肥料进行无损快速的检测分析。     

Graft copolymerization of acrylamide onto carboxymethyl starch

Water absorption resins of carboxymethyl starch graft acrylamide (CMS-g-AM) were synthesized by copolymerization based on a free radical reaction. At first, CMS was prepared with starch and chloroacetic acid in an alkali-methanol media. Then, AM was grafted onto CMS by using ceric ammonium nitrate as an initiator. The resulting graft products were identified by infrared spectra. The effects of the preparation conditions on the substituent degree (SD) of starch and the water absorption capacities of CMS-g-AM were investigated. The results showed that SD of starch first increased remarkably and then decreased gradually with increased addition of sodium hydroxide, and the water absorption capacity of CMS-g-AM depended greatly on the SD of CMS and its maximum with 0.75 of SD of starch was 350 g/g.     

Basalt fibers grafted with a poly(ionic liquids) coating for in‐tube solid‐phase microextraction

To improve the durability and extraction efficiency of an ionic liquid coating, 1‐dodecyl‐3‐vinylimidazolium bromide was polymerized and grafted onto basalt fibers for in‐tube solid‐phase microextraction. To develop an extraction tube, basalt fibers grafted with the poly(ionic liquids) coating were filled into a polyether ether ketone tube with a 0.75 mm inner diameter. The extraction tube was connected to high‐performance liquid chromatography system equipped with a sampling pump to build an online enrichment and analysis system. Using four common phthalates as model analytes, the extraction tube was investigated by the online analysis system. Good enrichment performance was exhibited by high enrichment factors ranging from 851 to 1858. Under the optimum conditions, an online analysis method was established, and good linearity (0.03–12 and 0.15–12 μg/L) and low limits of detection (0.01–0.05 μg/L) were achieved. This analysis method was applied to real samples including water in a disposable plastic box and the bottled water, some targets were detected but not quantified, and the relative recoveries spiked at 2, 5 and 10 μg/L were in the range of 86.4–119.5%.     

离子色谱-串联质谱法检测酒类产品中10种有机酸

建立了一种离子色谱-串联质谱(IC-MS/MS)测定白酒、黄酒、干红葡萄酒3种酒类样品中10种有机酸含量的方法。白酒样品氮吹后,经去离子水稀释,用IC-MS/MS分析检测;干红葡萄酒样品和黄酒样品,对比不同固相萃取小柱净化能力,最终选择石墨化炭黑固相萃取小柱进行净化,经去离子水稀释,用IC-MS/MS分析检测。选用高容量、强亲水性的Dionex IonPac^TM AS11-HC型阴离子分析柱进行分离,以淋洗液自动发生器在线产生的KOH水溶液为淋洗液,进行梯度淋洗。淋洗液经抑制器抑制后直接进入电喷雾电离串联质谱(ESI-MS/MS),采用负离子模式电离,多反应监测(MRM)模式检测,外标法定量。在该实验条件下:草酸、富马酸、马来酸、苹果酸、酒石酸、柠檬酸、奎尼酸和乌头酸在0.05~2 mg/L范围内线性关系良好;琥珀酸在0.05~5 mg/L范围内线性关系良好;乳酸在0.05~10 mg/L范围内线性关系良好(相关系数r²>0.99)。10种有机酸的检出限(S/N=3)在1.0~8.0 μg/L范围内,定量限(S/N=10)在3.5~26.5 μg/L范围内,在3个不同浓度的添加水平下,平均回收率在83.0%~112.1%之间,相对标准偏差≤9.1%,满足检测要求。该方法前处理简单,不使用有机溶剂,不需进行衍生化处理,测定快速、准确,灵敏度高,适用于3种酒类样品中10种有机酸的定量分析,为酒类食品的风味及品质测定提供方法支持。     

Single, binary and multi-component adsorption of copper and cadmium from aqueous solutions on Kraft lignin--a biosorbent

A new biosorbent for removing toxic metal ions from water/industrial wastewater has been investigated using by-product lignin from paper production. Lignin was extracted from black liquor waste, characterized and utilized for the removal of copper and cadmium from aqueous solutions in single, binary and multi-component systems. Adsorption studies were conducted at different temperatures, lignin particle sizes, pHs and solid to liquid ratios. All the studies were conducted by a batch method to determine equilibrium and kinetic parameters. The Langmuir and Freundlich isotherm models were applied. The Langmuir model fits best the equilibrium isotherm data. The maximum lignin adsorption capacities at 25 degrees C were 87.05 mg/g (1.37 mmol/g) and 137.14 mg/g (1.22 mmol/g) for Cu(II) and Cd(II), respectively. Adsorption of Cu2+ (68.63 mg/g at 10 degrees C and 94.68 mg/g at 40 degrees C) and Cd2+ (59.58 mg/g at 10 degrees C and 175.36 mg/g at 40 degrees C) increased with an increase in temperature. Copper and cadmium adsorption followed pseudo-second order rate kinetics. From kinetic studies, various rate and thermodynamic parameters such as effective diffusion coefficients, activation energy, and activation entropy were evaluated. Adsorption occurs through a particle diffusion mechanism at temperatures 10 and 25 degrees C while at 40 degrees C it occurs through a film diffusion mechanism. The sorption capacity of black liquor lignin is higher than many other adsorbents/carbons/biosorbents utilized for the removal of Cu(II) and Cd(II) from water/wastewater in single and multi-component systems.