离子色谱法检测含蛋白质食品中三聚氰胺

目的:建立离子色谱法检测含蛋白质食品中三聚氰胺的方法。方法:样品经冰乙酸溶液提取并沉淀蛋白,Dionex OnGuardⅡ RP样品前处理小柱除去脂肪等大分子有机物,采用Dionex IonpacCS17分离柱,3mmol/L H2SO4淋洗液等度淋洗,流速:1.2mL/min,在紫外波长240nm下检测。结果:三聚氰胺在0.5-50.0mg/L的范围内,质量浓度与色谱峰面积呈良好的线性关系(R2>0.9992),方法检出限(MDL)为0.06mg/kg,不同加标量的阴性样品加标回收率在84.8%-103.2%范围内,相对标准偏差RSD<4.0%。结论:该方法简便易行、快速,无干扰,不用有毒试剂,对环境友好,检测成本低,灵敏度高,检测结果准确度高,易于推广,适合对各种含蛋白食品中三聚氰胺的检测分析。     

离子色谱法测定饮用水中常见阴离子

本文主要介绍离子色谱法检测饮用水中常见阴离子的方法。本方法采用瑞士万通的761型离子色谱仪。分离柱为METROSEPAnionDual2,淋洗液为2.0mmol/LNaHCO3和1.3mmol/LNa2CO3抑制液为20mmol/LH2SO4在测定范围内,F-、Cl-、NO2-、NO32-;-SO42-的峰面积和质量浓度呈线性关系,相关系数均大于0.999。回收率F-为101.5%,CL-O101.6%,NO2-为108.0%.NO32-为97.7%,SO42-为103.3%。相对标准偏差在0.7%-4.3%之间。     

盐酸标准滴定溶液的标定及其不确定度的评定

按GB/T 601-2002《化学试剂标准滴定溶液的制备》中规定的方法配置并标定0.5mol/L盐酸标准滴定溶液,依据JJF l059.1-2012《测量不确定度评定与表示》建立不确定度评定程序和方法,评定其测量不确定度。当盐酸标准滴定溶液浓度为0.9987mol/L时,扩展不确定度为0.0022mol/L。     

GB/T 601-2016中盐酸标准滴定溶液标定浓度的不确定度评定

通过对GB/T 601-2016《化学试剂标准滴定溶液的制备》盐酸标准滴定溶液的浓度标定原理及试验步骤分析，根据JJF 1059.1-2012《测量不确定度评定与表示》规定，建立盐酸标准滴定溶液浓度平均值不确定度的数学模型，确定不确定度的各种来源，量化各不确定度分量以及合成标准不确定度，最终确定扩展不确定度，为保证滴定分析测量结果的准确性提供科学的指导。本文给出了盐酸标准溶液浓度标定的测量不确定度评定和表述的详细指导，具有较强的实用性和可操作性，可应用于基准试剂标定标准滴定溶液浓度时不确定度的评定，也便于进一步理解和有助于JJF1059.1-2012的实际应用。     

蚕豆保健品中左旋多巴的测定方法研究

建立蚕豆保健品中左旋多巴含量的高效液相色谱测定方法。样品经0.10 mol/L盐酸溶液超声提取20 min,XDB C18色谱柱分离,以甲醇-10 mmol/L磷酸二氢钾溶液(体积比2∶98)等度洗脱,280 nm下检测,外标法定量。结果表明:左旋多巴质量浓度在1.656~265.0 mg/L范围内与峰面积呈现良好的线性关系,方法的平均加标回收率为98.4%~100.9%,相对标准偏差为0.83%~2.18%,检出限为1.9 mg/kg,定量限为6.3 mg/kg。能够满足蚕豆保健品中左旋多巴含量的检测和质量控制需要。     

考来替兰磷酸盐结合率测定方法研究-离子色谱法

考来替兰磷酸盐结合率是临床前药物研究的一项重要内容,该文采用离子色谱法建立考来替兰对磷酸盐结合率的测定方法。采用电导检测器TSKguardcolumn Super IC-Anion HS保护柱及TSKgel Super IC-Anion HS色谱柱,淋洗液为Na_2CO_3(1.1mmol/L)/NaHCO_3(7.5mmol/L),流量为1.0 m L/min。结果表明,方法检出限为0. 02μg/m L,进样量在1.5～30μg/m L范围内线性关系良好(r~2=0.9994),精密度、重复性良好,测定结果的相对标准偏差为0.51%(n=6)。该方法简单方便、稳定可靠,可用于磷结合剂药物对磷酸盐结合率的测定。     

硫代硫酸钠标准滴定溶液浓度不确定度评定

在理化分析中,一切测量结果都不可避免地具有不确定度。硫代硫酸钠标准滴定溶液是一种常用化学定量参比物质,其标定值的准确性直接影响常规分析质量。现以GB/T601-2002《化学试剂标准滴定溶液的制备》为依据配制并标定硫代硫酸钠标准滴定溶液（0.1mol/L）,并根据JJF1135-2005《化学分析测量不确定度评定》对其标定浓度平均值进行不确定度评定,     

高效液相色谱法检测食品接触材料中三聚氰胺的残留量

建立了一种用液相色谱技术检测分析食品接触材料中三聚氰胺残留量的方法。样品采用0.1 mol/L盐酸作为提取溶液,70℃水浴超声提取。色谱分离采用NH2柱,流动相为V(乙腈):V(5mmol/L磷酸盐缓冲溶液,pH 6.5)=75:25,二极管阵列检测器检测。在优化条件下,三聚氰胺浓度在0.2-100 mg/L范围内与其峰面积线性关系良好,检出限(S/N=3)为0.02 mg/L。在100μg的添加水平下,三聚氰胺的回收率在80-99%之间,相对标准偏差(RSD)为2.80-4.32%。揭示了原料中三聚氰胺残留量与成型品的三聚氰胺迁移量的正相关关系。结果表明,该法简便、快速,可准确测定食品接触材料中三聚氰胺残留量。     

标准加入法对页岩气压裂返排液中COD的测试研究

以页岩气压裂返排液(高氯废水)中COD(化学需氧量)含量的测试方法为研究对象,考察测试体系中硫酸汞加量为0.2 g时能掩蔽的Cl-浓度,以此确定其稀释倍数,再结合相关标准对其未知的COD含量采用标准加入重铬酸盐法测定。结果表明,对长宁某平台页岩气压裂返排液稀释10倍后(使Cl-含量在2 000 mg/L以下),硫酸汞加量为0.2 g时,通过测试绘制标准曲线得到页岩气压裂返排液中COD含量为1 065 mg/L,测定结果相对误差≤±5%;对页岩气开采过程中其他废水COD测试适用性分析得出:标准加入重铬酸盐法测试结果的相对误差比国标重铬酸盐法小,仅为1.26%。通过研究标准加入重铬酸盐法对水样(特别是成分较为复杂的废水)中低浓度COD测量时,可屏蔽溶液中其他还原性离子对测试过程的影响,保证测试结果的准确性。     

标准滴定溶液4种标定方法的不确定度评定和探讨

标准滴定溶液浓度的标定方法有4种：（1）将一定质量的工作基准试剂溶解、定容,用移液管量取后标定;（2）用一定质量的工作基准试剂溶解后直接标定;（3）用浓度和不确定度已知的标准滴定溶液标定;（3）用浓度和不确定度已知的标准滴定溶液标定；（4）将一定质量的工作基准试剂溶解后直接配制标准滴定溶液。[第一段]     

Chiral separation of alkylamine antihistamines in pharmaceuticals by capillary isotachophoresis with charged cyclodextrin

Cyclodextrin-mediated capillary isotachophoresis (ITP) in cationic regime of the separation was developed for the separation and quantitation of alkylamine antihistamine dimethindene (DIM) and pheniramine (PHM) enantiomers in various pharmaceutical preparations (capsules, oral drops, gel, granulated powder). Several electrolyte systems of different compositions and pH were examined. The optimized chiral ITP electrolyte system was consisted of 10 mmol/L potassium acetate adjusted to pH 4.8 with acetic acid, containing 4 mmol/L negatively charged CE-β-CD (chiral selector) as the leading electrolyte with electroosmotic flow (EOF) suppressing additive, 0.2% (w/v) methylhydroxyethylcellulose (m-HEC), and 5 mmol/L β-alanine as the terminating electrolyte. The proposed electrophoretic method was successfully validated. It was convenient for the sensitive, simple, rapid, and highly reproducible assay of these antihistamine enantiomers. The calibration graphs relating the ITP zone length to the concentration of DIM and PHM enantiomers were rectilinear (r = 0.999) in the range 40.0-200.0 mg/L of each enantiomer. The relative standard deviations (RSD) were 0.75% for DIM(1), 0.63% for DIM(2), 1.05% for PHM(1), and 0.83% for PHM(2) (n = 6) when determining 100 mg/L DIM and PHM, respectively, standard solutions. According to the validation procedure based on the standard addition technique the recoveries were 97.66-98.34%. Good quantitation was obtained in short analysis time (a single analysis took about 12 min). The minimal sample pretreatment and low running costs make the proposed ITP method a good alternative to commonly used analytical methods (CZE, HPLC). The obtained results suggest that the proposed method is suitable for routine assay of dimethindene and pheniramine enantiomers in various pharmaceuticals.     

碳化二亚胺改性脱细胞猪真皮基质的性能研究

研究了0、10、20、30、40、50、100mmol/L碳化二亚胺室温下改性脱细胞猪真皮基质的基本性能.研究结果表明,随着EDC浓度的增高,自由氨基含量递减,收缩温度递增,并趋于一定值,产生了交联效应;表面接触角基本增大,吸水率和保水率趋于降低,表明改性后亲水性能有所降低;扫描电镜和孔率测定表明,不同浓度EDC改性对孔率未产生显著影响;断裂伸长率降低,材料脆性增强;抗张强度先随浓度的增加而升高,增至一定程度,强度变化较小,此后随浓度进一步升高而强度趋于降低.当浓度为30mmol/L时具有最高的反应速率和较好的综合性能.     

Chiral Separation of Alkylamine Antihistamines in Pharmaceuticals by Capillary Isotachophoresis with Charged Cyclodextrin

Cyclodextrin-mediated capillary isotachophoresis (ITP) in cationic regime of the separation was developed for the separation and quantitation of alkylamine antihistamine dimethindene (DIM) and pheniramine (PHM) enantiomers in various pharmaceutical preparations (capsules, oral drops, gel, granulated powder). Several electrolyte systems of different compositions and pH were examined. The optimized chiral ITP electrolyte system was consisted of 10 mmol/L potassium acetate adjusted to pH 4.8 with acetic acid, containing 4 mmol/L negatively charged CE-β?CD (chiral selector) as the leading electrolyte with electroosmotic flow (EOF) suppressing additive, 0.2% (w/v) methylhydroxyethylcellulose (m-HEC), and 5 mmol/L β-alanine as the terminating electrolyte. The proposed electrophoretic method was successfully validated. It was convenient for the sensitive, simple, rapid, and highly reproducible assay of these antihistamine enantiomers. The calibration graphs relating the ITP zone length to the concentration of DIM and PHM enantiomers were rectilinear (r = 0.999) in the range 40.0–200.0 mg/L of each enantiomer. The relative standard deviations (RSD) were 0.75% for DIM(1), 0.63% for DIM(2), 1.05% for PHM(1), and 0.83% for PHM(2) (n = 6) when determining 100 mg/L DIM and PHM, respectively, standard solutions. According to the validation procedure based on the standard addition technique the recoveries were 97.66–98.34%. Good quantitation was obtained in short analysis time (a single analysis took about 12 min). The minimal sample pretreatment and low running costs make the proposed ITP method a good alternative to commonly used analytical methods (CZE, HPLC). The obtained results suggest that the proposed method is suitable for routine assay of dimethindene and pheniramine enantiomers in various pharmaceuticals.     

Single-run capillary electrophoretic determination of inorganic nitrogen species in rainwater

A capillary electrophoretic (CE) method for the simultaneous determination of nitrate, nitrite, and ammonium ions has been developed. Direct (NO3-, NO2-) and indirect (NH4+) UV detection at 214 nm in conjunction with electromigration sampling from both ends of the capillary was used. The optimized separations were carried out in 10 mmol/L imidazole sulfate, 2 mmol/L 18-crown-6, and 0.02 mmol/L tetradecyltrimethylammonium hydroxide electrolyte (pH 4.0). The method permits excellent separation of three nitrogen species in only 4 min. A 1 x 10(-4) mol/L KBr solution was used as an internal standard to limit possible electrokinetic injection biases. Experimental results showed that the use of an anionic internal standard for cationic analytes and vice versa gives only slightly better precision than analysis with no internal standard. Using Br- internal standard for NO3- and NO2- ions and K+ for NH4+, peak area RSD values decrease significantly. The proposed system was applied to the speciation of inorganic nitrogen ions in rainwater samples. The recovery tests established for external calibration and standard addition techniques using one or two internal standards were within the range 100 +/- 10%. The CE results agree with those obtained by spectrophotometric methods.     

胶束增敏荧光光度法测定兔血样中阿霉素

基于阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)对蒽环类抗生素阿霉素的荧光强度有增敏作用,通过考察CTAB浓度、缓冲液pH及浓度、有机溶剂等对阿霉素荧光强度的影响,建立胶束增敏荧光光度法测定阿霉素的新方法。在体系为17mmol/L的硼酸缓冲液(pH 6.0)且含60%(v/v)乙醇、1.9mmol/L CTAB的条件下,阿霉素在0.5～120 ng/mL浓度范围内荧光强度呈良好的线性(r=0.999 2),检出限(3σ)为0.161 ng/mL。该方法用于测定兔血样中阿霉素时,回收率在93.7%～105.6%之间,相对标准偏差小于1.5%。结果表明该方法具有较好的准确度与灵敏度,可用于临床监测。     

Repeatability and Reproducibility Standard Deviations in the Measurement of Trace Moisture Generated Using Permeation Tubes

Permeation-tube moisture generators are used in industry as calibrated sources of water vapor and carrier gas mixtures. Measurements were made using three permeation-tube moisture generators of the type used in the semiconductor industry. This paper describes repeatability and reproducibility standard deviations in measurement of moisture concentration from such generators. Repeatability refers to measurements within a system and reproducibility refers to measurements between systems. Two independent methods were used to measure the realized concentration of water vapor. The first measurement, the calculated value, was determined using calibrated permeation rate of permeation-tube and flow rate of dry carrier gas. This is the industrial method of evaluating moisture concentration. The second measurement, the measured value, was determined using the low frost-point generator at the National Institute of Standards and Technology (NIST) and a quartz-crystal-micro-balance. Four pairs of independent measurements for each generator and for six nominal levels in the range from10 nL/L to 100 nL/L were made. The characteristic used to quantify repeatability and reproducibility standard deviations in industrial measurements is the calculated value minus the measured value. Repeatability standard deviation ranges from 1 nL/L to 2 nL/L, approximately. Reproducibility standard deviation ranges from 2 nL/L to 8 nL/L, approximately. The documentary ASTM standard E691-99 was used for both data validation and quantification of the repeatability and reproducibility standard deviations.     

高效毛细管电泳/电导检测法测定饮用水中的阴离子

本实验采用四乙烯五胺作为毛细管电泳的电渗流抑制剂,以10mmol/L Tris(三羟甲基氨基甲烷)+10mmol/L H3BO3(硼酸)+0.2mmol/L EDTA(乙二胺四乙酸)+0.2%(V/V)四乙烯五胺为电泳运行液,负高压分离(-15kV),电导检测,对饮用水中的Cl-、NO3-、SO42-三种阴离子进行了直接分离测定,并考察了分离电压,pH值,电解质溶液的组成及浓度,电渗流抑制剂,有机添加剂组成等对分离的影响。建立高效、快速的饮用水无机阴离子高效毛细管电泳/电导检测的分析方法。     

Investigation of electrolyte measurement in diluted whole blood using spectroscopic and chemometric methods

The feasibility of using near-infrared (NIR) spectroscopy in combination with partial least-squares (PLS) regression was explored to measure electrolyte concentration in whole blood samples. Spectra were collected from diluted blood samples containing randomized, clinically relevant concentrations of Na+, K+, and Ca2+. Sodium was also studied in lysed blood. Reference measurements were made from the same samples using a standard clinical chemistry instrument. Partial least squares (PLS) was used to develop calibration models for each ion with acceptable results (Na+, R2 = 0.86, CVSEP = 9.5 mmol/L; K+, R2 = 0.54, CVSEP = 1.4 mmol/L; Ca2+, R2 = 0.56, CVSEP = 0.18 mmol/L). Slightly improved results were obtained using a narrower wavelength region (470-925 nm) where hemoglobin, but not water, absorbed indicating that ionic interaction with hemoglobin is as effective as water in causing measurable spectral variation. Good models were also achieved for sodium in lysed blood, illustrating that cell swelling, which is correlated with sodium concentration, is not required for calibration model development.     

Dialysate bicarbonate variation in maintenance hemodiafiltration patients: Impact on serum bicarbonate,intradialytic hypotension and interdialytic weight gain

Introduction: The dialysate bicarbonate (DB) influences the acid‐base balance in dialysis patients. Very low and high serum bicarbonate (SB) have been related with a higher mortality. Acid‐base balance also has been associated with hemodynamic effects in these patients. The trial aim was to compare the effect of DB concentration variation on SB levels in maintenance hemodiafiltration (HDF) patients and the effect on intradialytic hypotension and interdialytic weight gain. Methods: A prospective study, with 9 months of follow‐up, involving 93 patients, divided in two groups: group 1 and group 2 with a DB of 34 mmol/L and 30 mmol/L, respectively, with monitoring of pre and post HDF SB, intradialytic hypotension, and interdialytic weight gain. Findings: Pre dialysis SB was higher in group 1: median concentration of 22.7 mmol/L vs. 21.1 mmol/L (P < 0.001). Post dialysis SB levels were higher in group 1: median concentration of 28.0 mmol/L vs. 25.3 mmol/L (P < 0.001). Post dialysis SB in alkalotic range was only detected in group 1 (51.2% of the patients). No significant differences were detected in intradialytic hypotension rate [28.0 vs. 27.4 episodes per 1000 sessions in group 1 and 2, respectively, (P = 0.906)] or in average interdialytic weight gain [2.9% vs. 3.0% in group 1 and 2, respectively, (P = 0.710)]. Discussion: DB of 30 mmol/L appears to be associated with SB levels closer to physiological levels than 34 mmol/L. The bicarbonate dialysate, in the tested concentrations, did not appear to have a significant impact on intradialytic hypotension and interdialytic weight gain in maintenance HDF patients.