Molecular weight determination of a newly synthesized guanidinylated disulfide-containing poly(amido amine) by gel permeation chromatography

A cationic gene delivery vector, guanidinylated disulfide-containing poly(amido amine)(CARCBA), was synthesized by Michael addition reaction between N,N′-cystaminebisacrylamide(CBA) and guanidine hydrochloride(CAR). Gel permeation chromatography(GPC) was used to evaluate the molecular weight of synthesized CAR-CBA. Polyethyleneimine(PEI) with molecular weight of 25 kDa was adopted as a reference, and polyethylene glycols(PEG) with different molecular weights were used to establish a standard curve for determining the molecular weight of CAR-CBA. The effects of two critical factors, namely columns and eluents,on the molecular weight measurement of CAR-CBA were investigated to optimize the GPC quantitative method. The results showed that Ultrahydrogel columns(120, 250) and HAc–NaAc(0.5 M, pH 4.5) buffer solution were the optimal column and GPC eluent, respectively.The molecular weight of the synthesized CAR-CBA was analyzed by the optimized GPC method and determined to be 24.66 kDa.

Gel Permeation Chromatography Purification and Gas Chromatography-Mass Spectrometry Detection of Multi-Pesticide Residues in Traditional Chinese Medicine

The measurement of 23 organochlorine, organophosphorus, and pyrethroid pesticides in typical traditional Chinese medicine (TCM), flos lonicerae, was made using gel permeation chromatography (GPC) purification and gas chroma- tography-mass spectrometry (GC-MS) detection. The pesticides were extracted with ultrasonic device and 5.0 mL mixture of ethyl acetate and cyclohexane (1:1, v/v). Coextractants from sample matrices which may have interfere to the qualitative and quantitative analysis, such as pigments, were removed using GPC purification. Simultaneous full scan and selective ion monitor (scan/SIM) mode for GC-MS was used for qualitative and quantitative analysis, which pro- vided retention time and characteristic fragments ratio for each pesticide so as to positively identify each analyte. Rela- tive standard deviations (RSDs) were within 7.7% (5.0 - 22.5 μg/kg, n = 3). The recoveries of pesticide standards at the spiked concentration of 5.0 - 22.5 μg/kg were between 87.1% and 110.9%. Limits of detection (LODs) for the analytes were 0.16 - 3.2 μg/kg, which could meet the demand of routine analysis and TCM quality control.

Determination of Steroid Hormone Residues in Fish Tissues Using Gel Permeation Chromatography and Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

A highly sensitive method was developed for the simultaneous determination of 8 steroid hormones in high-fat fish tissues using ultra high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The 8 steroid hormones were extracted from the tissues with diethyl ether.Differing from other common purification methods,the extract solutions were cleaned by gel permeation chromatography(GPC) using ethyl acetate-cyclohexane solution(1:1,v/v) as the mobile phase.The separation of target compounds was carried out by a BEH C18 column and a gradient elution consisting of acetonitrile and 0.2% aqueous formic acid(v/v).The compounds were detected under the multiple reaction monitoring(MRM) mode and quantified with external standard method.This method was validated with respect to linearity,specificity,accuracy and precision.A linearity with correlation coefficient larger than 0.995 was achieved in the range of 0.5 to 50 ng m L^(-1).The average recoveries at the spiked levels of 1.0,5.0,and 10.0 μg kg^(–1) varied between 81.7% and 90.8%,with the relative standard deviations(n=5) ranged from 3.50% to 10.0%.The limit of quantification(LOQ) for 8 steroid hormones ranged from 0.2 to 1.5 μg kg^(-1).It was concluded that this method can be successfully applied for the determination of 8 steroid hormones in complicated matrices including high-fat fish tissues.

GEL PERMEATION CHROMATOGRAPHIC ANALYSIS OF LACQUER POLYSACCHARIDE

Ten fractionated samples of Chinese lacquer polysaccharide in aqueous 0.1M NaC1 solution were studied by aqueous-phase gel permeation chromatography （GPC）. The universal calibration, broad MWD calibration and corrected column dispersion were adopted to the analysis of GPC chromatograms of the polysaccharide. The molecular weights M;, M;and polydispersity index M;/M;obtained from GPC are in good agreement with the results of light scattering and membrane osmometry. It is verified that the universal calibration concept is applicable to the lacquer polysaccharide having a number of side chains.

Determination of 14 Organophosphorus Pesticide Residues in Mutton by Gel Permeation Chromatography-Gas Chromatography-Mass Spectrometry(GPC-GC-MS)

[Objectives]This study was conducted to purify mutton samples by gel permeation chromatography(GPC).[Methods]Fourteen organophosphorus pesticide residues in samples were qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry(GC-MS)in selective ion scanning mode(SIM).[Results]The organophosphorus pesticide standard solutions showed good linearity in the mass concentration range of 0.1-10.0μg/ml with correlation coefficients(r)not lower than 0.999,and the detection limits(S=3 N)ranged from 0.01 to 0.05 mg/kg.The average recovery values were in the range of 80.2%-99.7%,with relative standard deviations(RSDs,n=3)in the range of 1.8%-6.3%,at the addition levels of 0.5,1.0 and 2.0 mg/kg.[Conclusions]The method is simple,sensitive and accurate,and can be used for the determination of organophosphorus pesticide residues in mutton.

聚乙烯相对分子质量及其分布快速评价方法研究

以国内外采用不同工艺和催化剂生产的17种聚乙烯的测试结果为基础,通过理论推导与模型拟合相结合,建立了以熔体流动速率快速计算相对分子质量及其分布的方法,并由此计算出数均分子量。经验证,该方法准确性较好,可弥补凝胶渗透色谱法的不足,有利于装置生产过程中准确控制产品质量和提高新产品开发效率。

凝胶渗透色谱-光散射联用表征聚合物摩尔质量的实验教学改革

凝胶渗透色谱-光散射(gel permeation chromatography-light scatting,GPC-LS)联用是目前最常用的表征聚合物摩尔质量的方法之一,具有灵敏度高、结果准确等特点,在科学研究与生产实践中得到了广泛应用。“凝胶渗透色谱-光散射联用表征聚合物摩尔质量”是《高分子物理实验》课程中一个重要的教学内容。然而,目前的GPC-LS实验教学内容简单,缺乏深度。本文在该实验项目原有内容的基础上进行扩充,重新设计出多套实验项目:(1)选取商品化的聚苯乙烯为实验样品,利用GPC-LS对其摩尔质量、摩尔质量分布以及回转半径等分子结构参数进行表征;(2)选取两种分子结构参数接近的聚丙烯腈样品,借助质量微分分布曲线揭示这两种样品在摩尔质量分布中的细微差别;(3)选取一系列不同摩尔质量的聚乙二醇为实验样品,通过比较其色谱图分析摩尔质量的高低对色谱峰的影响;(4)选取3种不同的聚合物(聚丙烯腈、聚甲基丙烯酸甲酯、聚β-环糊精)样品,借助构象图对其分子链的构象进行分析。此外,本文对实验教学方法进行了改革,将被动学习转变为主动学习,提高了学生的自主学习能力。通过本实验项目的教学改革探索,使学生能更加全面地理解凝胶渗透色谱-光散射联用的原理及应用,开拓了学生的知识视野,激发了学生的学习热情,提升了实验教学效果。

凝胶渗透色谱测试天然橡胶相对分子质量及分布的优化方法建立

为摸索凝胶渗透色谱仪器测试条件对天然橡胶相对分子质量及分布测试结果的影响,利用凝胶渗透色谱对同一天然橡胶样品进行分子量及分布测试,确定了最佳的凝胶渗透色谱测试条件:检测器为示差折光检测器,流动相为四氢呋喃,流速为1.0mL/min,柱温和检测器温度为40℃,进样体积为30μL。将其运用在不同品种天然橡胶样品的测试分析中,结果表明该方法准确度高(>98%),重现性好(RSD<5%),为今后利用凝胶渗透色谱仪测试天然橡胶相对分子质量及分布测试提供了试验指导和理论基础。

Bio-Gel P-2分离低聚木糖的特性

以聚丙烯酰胺凝胶（Bio-Gel P-2）为层析介质，快速蛋白液相层析（FPLC）系统为平台，以脱气超纯水为洗脱液，对其分离低聚木糖的特性进行了探讨。研究表明，Bio-Ge lP-2可用于低聚木耱分离，采用Bio-Gel P-2分离低聚木糖时，木二糖至木六糖各相邻组分之间的选择因子α和分离度R分别介于1．13～1．18和0．83～1．11之间，而且各组分与层析介质Bio-Gel P-2之间无特异性吸附现象，能完全按照分子质量大小进行分离。通过1次分离可获得纯度分别为86．94％、82．90％、88．30％、64．20％和77．89％的木二糖至木六糖溶液。

生物样品中新污染物筛查:透析和凝胶渗透色谱联用净化方法

以河蚬为代表,建立了一种能有效去除生物样品中脂肪及其它内源性干扰物,并保留性质广泛的新污染物的净化方法。选择理化性质迥异的35种污染物(log Kow为-1.30~8.41),优化生物样品萃取、透析及凝胶渗透色谱(GPC)分离方法,并验证了方法可行性。优化的样品前处理方法为:样品先后采用正己烷、丙酮、二氯甲烷混合溶液(体积比2∶2∶1)和乙腈加速溶剂萃取,提取液经4次透析后再用GPC净化,目标物使用气相色谱-质谱和液相色谱-串联质谱进行分析。采用香兰素-磷酸法测定每一净化步骤后样品的脂肪含量,并结合色谱-质谱全扫描分析,检验干扰物的去除效率。结果表明,净化后河蚬提取物中残余的脂肪含量小于1.06%,GPC中待测分析物的流出时间为8~20 min,平均回收率为55.1%±13.0%,相对标准偏差为1.4%~9.2%。净化后的河蚬生物样品中脂肪和部分内源性物质被有效去除,宽泛程的目标物的回收率均达到环境样品痕量新污染物检测的要求,所建方法可用于生物样品非目标筛查的前处理。

The effect of reactive plasticizer on viscoelastic and mechanical properties of solid rocket propellants based on different types of HTPB resin

Conventional plasticizers deteriorate mechanical and viscoelastic properties of the propellants due to their migration upon aging and long-term storage,which affects reliability and safety properties during exploitation.To address this issue,conventional plasticizer,dioctyl adipate(DOA),is replaced by reactive one,castor oil(CO).In addition,three different types of HTPB were used to obtain propellants with designed viscoelastic and mechanical properties.The CO increased propellants viscosity,without a significant impact on the propellant processability,regardless to the type of prepolymer.Conversely,mechanical properties were different depending on the type of resin,which were further analyzed by gel permeation chromatography(GPC).Addition of CO formed a denser polymer network and shifted T_(g) to higher values,compared to the compositions with DOA.The tensile strength of CO-containing propellants was lower at +20℃ and +50℃ compared to the reference compositions,while the strain at maximum load and strain at break were significantly increased with pronounced plastic deformation,especially for samples at -30℃.The inclusion of CO in the propellants composition gives more room for adjusting a wide range of mechanical properties.

加速溶剂萃取-凝胶渗透色谱-气相色谱-质谱法同时测定水产品中短链及中链氯化石蜡

目的建立加速溶剂萃取-凝胶渗透色谱-气相色谱-电子捕获负化学源-低分辨质谱法同时测定水产品中短链氯化石蜡(short chain chlorinated paraffins,SCCPs)和中链氯化石蜡(medium chain chlorinated paraffins,MCCPs)的分析方法。方法水产品样品经冷冻干燥后,加入适量硅藻土混合并研磨均匀,以二氯甲烷/正己烷(1:1,V:V)对目标物进行萃取(100℃、1500 psi),收集凝胶渗透色谱仪9~21 min馏出液,浓缩定容后上机。结果采用气相色谱-电子捕获负化学源-低分辨质谱法测定水产品中SCCPs和MCCPs,方法检出限分别为16.2ng/g(n=7)和17.9ng/g(n=7),低(50ng/g)、中(100ng/g)、高(500ng/g)3个水平的加标回收率为80.8%~95.2%,相对标准偏差为4.53%~8.48%。采用该方法对采集的不同水产品样品进行分析,样品中SCCPs和MCCPs检出率为69.7%和63.6%,检出含量分别为24.7~2632.0ng/gdw和3.88~360.00ng/gdw。SCCPs和MCCPs在不同水产品中的分布模式相似,碳原子同族体SCCPs以C_(10)和C_(11)为主,MCCPs以C_(14)和C_(15)为主,氯原子同族体以Cl_(5)~Cl_(7)为主。结论本研究建立的方法灵敏度高、重现性好且自动化程度高,可有效提升检测效率,适用于水产品中短链和中链氯化石蜡的检测。

加速溶剂萃取-凝胶净化色谱-气相色谱质谱法测定农用地土壤中有机氯农药方法研究

通过对加速溶剂萃取、平行蒸发及净化方法等环节的优化实验,建立了加速溶剂萃取凝胶净化色谱气相色谱质谱法测定农用地土壤中23种有机氯农药的检测方法。结果表明,方法检出限为0.0034~0.0052 mg/kg;对化合物质量分数为0.25 mg/kg的土壤加标样品进行平行实验,回收率为82.0%~93.7%;测定结果的相对标准偏差(RSD)≤8.7%。对土壤有证标准质控样品进行分析,测定结果均在验收范围之内。该方法准确可靠,灵敏度较高,样品净化效果较好,能够满足农用地土壤中有机氯农药残留痕量分析的要求。

HPGPC-RID法测定右旋糖酐20分子量及其分布的可行性研究

目的 建立高效凝胶渗透色谱-示差折光检测器(HPGPC-RID)测定右旋糖酐20分子量及其分布的方法,并对该方法进行可行性研究。方法 对新建方法进行专属性、准确度、重复性及耐用性验证,并评价新建方法与《中国药典》2020版(二部)收录方法检测结果的等效性。结果 新建方法专属性、准确度、重复性、耐用性良好,且与药典方法等效,可用于右旋糖酐20分子量及其分布的测定。与此同时,新建方法能避免药典方法中硫酸钠(Na_(2)SO_(4))峰对右旋糖酐20峰的干扰。结论 相比于药典方法,新建方法对右旋糖酐20分子量及其分布测定具有更好的适用性。

Thermal aging behavior of high performance poly(vinyl alcohol) hydrogel

The thermal aging behavior of poly （ vinyl alcohol ） （ PVA ） hydrogel was studied at four different temperatures of 40 ℃, 50 ℃, 60 ℃ and 70 ℃ in one year. The samples of PVA hydrogel were closely covered by plastic film. The changes of their chemical structures and physical properties during aging were measured through different measurable techniques including tensile testing, gel permeation chromatography （ GPC ）, viscosity analysis, and Fourier transform infrared （FTIR） spec- trum. The results showed that the molecular weight of PVA in hydrogel changed little with time and temperature. FTIR spectra of PVA in all the samples were similar to those of the original samples. The tensile strength of PVA hydrogel didn＇t change until the 330th days.

Development of Different Strategies for the Clean-Up of Polychlorinated Biphenyls (PCBs) Congeners Using Pressurized Liquid Extraction

The extracted fish samples (w/w) using pressurized liquid extraction (PLE) were cleaned up by applying different adsorbent materials such as: combination of acidic/ basic silica and alumina, florisil, and silica gel either alone or in combination with another sort of sorbent. Different solvents such as hexane (H), dichloromethane (DCM), with different compositions were used to elute the PCBs target compounds from the spiked fish samples. Overall the mean percentage recoveries for all PCBs congeners using PLE were ranging from 78.6% to 98.7%;from 79.4% to 91.8%;from 65.8% to 104.5% and from 82.4% to 100.9% for cases A, B, C, D and E, respectively. However, the overall mean percentage recoveries for the 13C-PCBs surrogate including: 101, 138, 153, 180 and 209 were ranging from 88.2% to 97.6%;from 79.4% to 90.2%, from 88.3% to 96.4%, from 79.8% to 90.4% and from 83.9% to 95.9%, for cases A, B, C, D and E, respectively. The limits of detection of the proposed method were varied from 0.01 to 0.28 ng/g (w/w) for different PCBs congeners. The proposed method has linear dynamic range from 21.5 ng/g to 109 ng/g. This method was applied to fish samples for the determination of the target PCBs components.

超高效液相色谱法定量检测干果中20种酸性染料

该研究建立了超高效液相色谱-二极管阵列检测器法测定干果中20种酸性染料的方法。方法采用乙腈-水(体积比17∶3)为提取溶剂,提取液经凝胶色谱柱净化,以及选用C18柱进行分离,经二极管阵列检测器进行目标痕量水平检测。结果表明,该方法具有良好的线性范围(10~50μg/mL),相关系数(r)大于0.9883,检测限为0.01~0.26μg/g,回收率为71%~114%,相对标准偏差(n=6)为0.80%~7.5%。经检验,该方法具有高灵敏度和可靠性,可同时检测食品中的20种酸性染料。

云南烤烟KRK26特征香气分析

【目的】探究烤烟品种KRK26香韵风格,分析其重要致香成分及内在关系,为开发其工业可用性提供参考依据。【方法】通过感官辅助凝胶渗透色谱(gel permeation chromatography,GPC)分离筛选出关键香韵特征组分,采用气相色谱—质谱联用仪分析确定特征组分的重要致香成分,并结合相对香气活力值进行关键香气成分分析。【结果】感官辅助GPC分离得到5个(F2~F6)具有明显香韵特征的组分,其中,F2~F3清香香韵明显,F5~F6则呈焦甜香香韵。F2组分香韵特征以清甜香为主,辅以豆香,关键香气成分为金合欢醇和对甲基苯乙酮;F3组分带有强烈的清香,伴有花香和干草香韵,关键香气成分为金合欢醇和α-亚麻酸;F4组分以浓烈的花香和果香为主,底部有浓烈干草香香韵,关键香气成分为(+)-柠檬烯、柠檬醛、茄酮和香叶醇等;F5组分以苯乙酸带有的蜜甜香为主,辅以轻微焦甜香香韵;F6则具有强烈的焦甜香香韵,关键香气成分为麦芽酚和5-羟甲基糠醛等。【结论】KRK26香气风格以清香和焦甜香香韵为主,辅以花香和果香等香韵特征。

QuEChERS-在线凝胶渗透色谱-气相色谱-串联质谱法高通量筛查动物源性食品中的多农药残留

将QuEChERS技术与在线凝胶渗透色谱-气相色谱-串联质谱(GPC-GC-MS/MS)技术结合,建立了动物源性食品中196种农药残留的高通量检测方法。样品经乙腈提取、QuEChERS结合在线GPC净化后,进行GC-MS/MS检测,多反应监测模式(MRM)分析,外标法定量。方法优化了提取溶剂及净化剂类型,实现了目标物的高效提取和基质的有效去除;考察了在线GPC对样品溶液的净化作用。通过研究不同馏分接收时间段内目标物的回收率和基质效应,得出最佳馏分接收时间,实现目标物的有效导入和基质的高效去除,并对QuEChERS-GPC联用技术的优势进行了评价。该方法研究了196种农药的基质效应,其中10种农药表现为中等强度基质效应,4种农药为强基质效应。本研究采用基质匹配标准溶液进行定量,结果表明,196种农药在0.005~0.2 mg/L范围内线性关系良好,相关系数均>0.996,方法的检出限为0.002 mg/kg,定量限为0.005 mg/kg。向猪肉、牛肉、猪肝3种不同脂肪含量基质的空白样品中添加标准溶液,196种农药在3个加标水平下(0.01、0.05、0.20 mg/kg)的平均回收率为65.3%~126.2%,精密度为0.7%~5.7%。本方法快速、准确、灵敏,适用于动物源性食品中多农药残留的高通量筛查与检测。

加速溶剂萃取-凝胶渗透色谱-气相色谱-串联质谱法测定鱼类中7种新型有机污染物

目的建立加速溶剂萃取-凝胶渗透色谱-气相色谱-串联质谱法同时测定鱼类中7种新型有机污染物(咔唑和卤代咔唑类化合物)的分析方法。方法样品与硅藻土研磨混匀后经加速溶剂萃取仪提取,使用凝胶渗透色谱法净化并氮吹至近干,用1mL丙酮复溶。目标化合物采用多反应监测(multiplereactionmonitoring,MRM)模式分析,外标法进行定量。结果咔唑、3-氯咔唑、3-溴咔唑和3,6-二氯咔唑在0.5~50.0μg/kg范围内线性关系良好,相关系数r>0.997;3,6-二溴咔唑、2,7-二溴咔唑和1,3,6,8-四溴咔唑在1.0~100.0μg/kg范围内线性关系良好,相关系数r>0.998。定量限(limits of quantification,LOQs)在0.50~1.00μg/kg之间,在各目标物的1LOQs、2LOQs和10LOQs3个加标水平下,7种咔唑和卤代咔唑类化合物的平均回收率为87.22%~107.27%,相对标准偏差(relative standard deviations,RSDs)为2.70%~8.17%(n=6)。结论该方法自动化程度高、灵敏度高、稳定性好,适用于鱼类中7种咔唑和卤代咔唑类化合物的检测。