离子色谱法测定水中五种无机阴离子系统检测条件优化

采用离子色谱法分析了水中常见的5种无机阴离子【氟离子、氯离子、硫酸根、硝酸根(以N计)、亚硝酸根(以N计)】的含量,在氢氧根淋洗液体系下通过调整系统参数,优化了几种阴离子的系统检测条件,大大缩短了分析所需时间,提升了工作效率。结果表明:使用AS11-HC阴离子分离柱对5种无机阴离子进行分离,最佳流速为1.2 mL/min,最佳柱温和池温范围在30~32℃时,系统压力在可控范围内,8 min即可同时分离检测上述5种无机阴离子,方法具有良好的线性,相关系数为0.9995~0.9998,经检出限、平行样及有证标准物质验证,结果均满意。该检测条件分析5种无机阴离子,具有简便、快速、灵敏等优点。

改进和优化黑果枸杞及其制品中花青素测定的pH示差法

建立一种基于美国官方分析化学师协会(Association of Official Analytical Chemists,AOAC)方法检测黑果枸杞及其制品中花青素含量的改进pH示差法。考察了黑果枸杞及其制品中花青素的最佳提取和检测条件,通过液相色谱-三重四级杆串联质谱法鉴别出黑果枸杞中花青素的具体化学结构,并计算出混合花青素的平均摩尔质量。通过分光光度法测得混合花青素的平均摩尔消光系数,对改进后的pH示差法进行方法学验证和花青素的含量测定。结果显示,最佳提取和检测条件如下:黑果枸杞花青素提取溶剂为盐酸-80%(体积分数)乙醇(3∶97,体积比),料液比为1∶100(g∶mL),提取温度为50℃,提取时间为30 min,缓冲溶液稀释5倍后静置平衡20 min。液相色谱-三重四级杆串联质谱法鉴别黑果枸杞中主要以矮牵牛素类花青素为主(占97.96%),黑果枸杞特有的混合花青素平均摩尔质量为912.7 g/mol,平均摩尔消光系数为29591 L/(mol·cm)。pH示差法改进后能够满足方法学验证要求,固体样品和液体样品最低检出限分别为28.2 mg/100 g、0.282 mg/100 mL。方法改进后花青素提取增长率均大于20%,静置平衡20 min后单次检测结果精密度小于0.3%。以矮牵牛素类花青素代替矢车菊素-3-O-葡萄糖苷计算花青素含量平均提高了2.41倍,能真实地反映黑果枸杞及其制品中花青素的含量。

涡流脉冲热像技术中检测条件的粒子群优化

涡流脉冲热像检测中的检测条件优化是最大化裂纹区域生热量以充分发挥检测系统性能的重要保证。针对检测条件选择人工依赖性强等问题,以含有特定尺寸疲劳裂纹的金属平板试件为研究对象,采用仿真和实验相结合的方法,分析了检测条件对裂纹热响应的影响特点,结果表明:裂纹热响应随着激励时间、激励强度的增加而增强;随着提离距离的增加呈现先增强后减弱的趋势。基于仿真与实验结果,提出了一种用于估算特定检测条件下裂纹热响应的多元非线性回归模型,确定了裂纹热响应与不同检测条件之间的定量化关系。最终引入粒子群优化算法进行了检测条件优化,给出了热响应分布图和检出概率分布图。研究成果为涡流脉冲热像检测中的检测条件优化提供理论指导。

高效液相色谱-串联质谱法检测动物源性食品中泰地罗新残留

为建立适用于动物源性食品中泰地罗新残留量检测的高效液相色谱-串联质谱法(HPLC-MS/MS),本研究对色谱、质谱、净化条件和定溶液等进行检测条件优化,建立了测定动物源性食品中泰地罗新残留量的检测方法,验证其线性范围、检出限,并以猪、牛、羊肉及其内脏等动物源性食品为试验样品,测定其回收率及精密度。结果表明,色谱条件以Aglient ZORBAX SB C18为色谱柱,乙腈-0.1%甲酸水为流动相;质谱条件以734.4 m/z为母离子,98.2和174.4 m/z为子离子;净化条件以HLB(150 mg,6 mL)固相萃取柱为净化柱,5 mL 50%甲醇水溶液为上样溶液,5 mL 5%氨水乙腈为洗脱溶剂;定容液为0.1%甲酸水-乙腈(v/v,9/1)。该方法在5~50μg/L范围内线性良好,线性相关系数为0.999 7,检出限为5μg/kg,动物源性食品的泰地罗新回收率81.8%~110.6%,相对标准偏差在1.38%~7.14%。本方法准确度较高,适用于动物源食品中泰地罗新残留量检测。

一种同时测定12种香型白酒中35种骨架风味物质的方法

为解决一种快速定量12大香型白酒中35种骨架风味物质的需求,该研究采用气相色谱(GC)法建立了一种同时测定白酒中35种骨架风味物质的方法,考察色谱条件(色谱柱、载气流速、进样口温度及检测器温度)对化合物分离度的影响,并进行方法学考察。在此基础上,采用正交偏最小二乘法-判别分析(OPLS-DA)对不同产地、香型白酒中差异挥发性风味物质进行分析。结果表明,最佳色谱条件为HP-INNOWAX色谱柱,载气流速1.5 mL/min、进样口温度250℃、检测器温度250℃。该方法检出限(LOD)为0.31~1.89 mg/L、定量限(LOQ)为1.02~6.30 mg/L,35种骨架风味物质在质量浓度0~50 mg/L范围内线性关系良好,相关系数R2≥0.998,平均加标回收率为80.2%~109.2%,精密度试验、重复性试验、稳定性试验结果的相对标准偏差(RSD)分别为0.3%~2.6%、0.4%~4.8%、0.3%~5.1%。OPLS-DA结果表明,不同产地、香型白酒主要差异性风味物质为己酸乙酯、正丙醇等。

Optimization of Chromatographic Conditions for Detecting Ellagic Acid in Pomegranate Peels Using HPLC Method

[Objective] This study aimed to optimize the chromatographic conditions for detecting ellagic acid in pomegranate peels using HPLC method. [Method] By using 0.2 mg/ml ellagic acid standard solution, on the basis of single-factor experiment and orthogonal experiment, chromatographic conditions （mobile phase ratio, flow rate, col- umn temperature） for detecting ellagic acid using HPLC were optimized. Based on the optimal chromatographic conditions, the ellagic acid content in experimental pomegranate peels was determined. [Resull] The optimal chromatographic conditions for detecting ellagic acid in pomegranate peels using HPLC method are： 1.2% phos- phoric acid：acetonitrile=85：15, column temperature of 35 ℃, and flow rate of 1.0 ml/min. The linear regression equation of ellagic acid is： y=2.9e＋0.6x＋4.4e＋5 （FF=9 999）. Ac- cording to the standard addition recovery test, the average recovery rate of ellagic acid is 98.20%, and RSD is 0.60%. Under above optimized chromatographic condi- tions, ellagic acid can be well separated from other interfering components in pomegranate peels, with shorter peak time and ideal effect, which is convenient for the detection in production practices. [Conclusion] This study laid the foundation for detecting ellagic acid in pomegranate peels using HPLC method.

Optimization of Ultrasonic Extraction and Clean-up Protocol for the Determination of Polycyclic Aromatic Hydrocarbons in Marine Sediments by High-performance Liquid Chroma-tography Coupled with Fluorescence Detection

The procedures of ultrasonic extraction and clean-up were optimized for the determination of polycyclic aromatic hydrocarbons (PAHs) in marine sediments. Samples were ultrasonically extracted, and the extracts were purified with a miniaturized silica gel chromatographic column and analyzed with high performance liquid chromatography (HPLC) with a fluorescence detector. Ultrasonication with methanol-dichloromethane (2:1, v/v) mixture gave higher extraction efficiency than that with dichloromethane. Among the three elution solvents used in clean-up step, dichloromethane-hexane (2:3, v/v) mixture was the most satisfactory. Under the optimized conditions, the recoveries in the range of 54.82% to 94.70% with RSDs of 3.02% to 23.22% for a spiked blank, and in the range of 61.20% to 127.08% with RSDs of 7.61% to 26.93% for a spiked matrix, were obtained for the 15 PAHs studied, while the recoveries for a NIST standard reference SRM 1941b were in the range of 50.79% to 83.78% with RSDs of 5.24% to 21.38%. The detection limits were between 0.75 ng L-1 and 10.99 ng L-1for different PAHs. A sample from the Jiaozhou Bay area was examined to test the established methods.

高效液相色谱-串联质谱法测定水中全氟辛烷磺酸含量

建立了水中全氟辛烷磺酸(perfluoro-rooctane sulfonate, PFOS)的高效液相色谱-串联质谱法分析方法。用0.22μm PP滤膜过滤水样,Poly-Sery HLB固相萃取柱对200 mL水样进行富集处理,以质量分数为10%的甲醇水溶液淋洗HLB柱以去除表面杂质,随后抽真空,再用4 mL纯甲醇溶液洗脱HLB柱。取洗脱液上机检测,以质量分数为0.1%的甲酸为流动相A,甲醇为流动相B,采用ACQΜITYΜPLC BEH C;色谱柱对洗脱液进行分离,负离子多反应监测模式检测,碎片离子m/z=80,内标法定量分析。在优化条件下,PFOS在0.01~50μg/L范围内线性较好,相关系数r>0.99,方法检出限为0.25μg/L。方法加标回收实验添加浓度0.2、2.0和20μg/L,PFOS加标回收率为82.1%~104.5%,相对标准偏差(RSD)为2.34%~5.64%。采集湖泊及养殖虾塘进出口水样进行测定,其PFOS含量均低于检出限,其中,湖水加标回收率为84.75%~112.2%,RSD<5.62%,养殖塘水样加标回收率为81.7%~118.6%,RSD<7.51%,实验所建方法可方便准确地检测水中PFOS含量。