The conventional protein chromatography technique was adopted to purify the antifreeze proteins (AFPs) from the leaves of Ammopiptanthus mongolicus (Maxim.) Cheng f. Two bands on native PAGE gel showed thermal hys...The conventional protein chromatography technique was adopted to purify the antifreeze proteins (AFPs) from the leaves of Ammopiptanthus mongolicus (Maxim.) Cheng f. Two bands on native PAGE gel showed thermal hysteresis activity, one was band B1, whose thermal hysteresis was 0.46 ℃ at 8 g/L, which showed two bands (67 kD, 21 kD) on SDS_PAGE gel; the other was B3, whose thermal hysteresis was 0.45 ℃ at 10 g/L, and it contained only a single protein (39.8 kD). Both B1 and B3 are not glycoproteins, because neither do they interact with Shiff_reagent, nor show ultraviolet characteristics of a typical glycoprotein.展开更多
The determination of synthetic phenolic antioxidants （SPAs） including propyl gallate （PG）, tertiary butyl hydroquinone （TI3HQ）, butylated hydroxyanisole （BHA） and butylated hydroxytoluene （BHT） in food items...The determination of synthetic phenolic antioxidants （SPAs） including propyl gallate （PG）, tertiary butyl hydroquinone （TI3HQ）, butylated hydroxyanisole （BHA） and butylated hydroxytoluene （BHT） in food items is reported using high performance liquid chromatography （HPLC）. A Cls column is used as the stationary phase, acetonltrile and water：Acetic acid （1%） is used as the mobile phase of gradient elution and the UV detec- tor is set at 280 nm. Under the above conditions, four antioxidents is completely separated within 8 rain. The limit of detection, linear range, and reproducibility of HPLC are evaluated. Isolation parameters of SPAs from different types of food items （cooking oil, margarine and butter, and cheese） are optimized. SPAs are extracted from food items through extraction with methanol/acetonitrile （1 ： 1, in volume）, vortex, ultrasonic treatment and precipitation in a freezer （2 h）. For cooking oil margarine, butter and cheese at 50 and 200 rag/L, recoveries of SPAs are 93.3%0--108.3% （PG）, 85.3~^--108.3~~ （TBHQ）, 96.7~^--101.2~/6 （BHA）, and 73.9^-- 94.6% （BHT）. The method is applied to the determination of SPAs in 38 food items （16 cooking oils, 8 mar- garine, 6 butter and 6 cheese samples）. The levels of SPAs in positive samples are all below the legal limits of China.展开更多
In the present study, we developed and validated a simple and sensitive gradient elution liquid chromatography tandem mass spectrometry （LC-MS/MS） method for quantification of doxorubicin in rabbit plasma. Daunorubi...In the present study, we developed and validated a simple and sensitive gradient elution liquid chromatography tandem mass spectrometry （LC-MS/MS） method for quantification of doxorubicin in rabbit plasma. Daunorubicin was used as an internal standard （IS）. The doxorubicin and IS were extracted with ethyl acetate from plasma samples. The chromatographic separations were achieved on a C18 column （2.1 mm×50 mm, 2.5μm） configured with a C18 guard column （2.1 mm×10 mm, 2.5 μm）. The mobile phase of 0.1% formic acid-water solution and acetonitrile was delivered using a gradient elution program at a flow rate of 0.4 mL/min. The temperature for column was maintained at 40 ℃. The electrospray ionization （ESI） source was operated in the positive ion mode, and the quantification was conducted using multiple reaction monitoring （MRM） of the transitions m/z 544.07→396.96 and m/z 528.06→321.05 for doxorubicin and IS, respectively. The calibration curve of doxorubicin was linear （r 〉 0.999） within the range of 2-600 ng/mL. The lower limit of quantification was 2 ng/mL. The relative errors of intra-day and inter-day accuracies ranged from -2.48% to 0.18% and from -3.78% to 1.94%, respectively. The relative standard deviations of intra-day and inter-day precisions were less than 8.65% and 6.41%, respectively. The method exhibited satisfactory results in terms of specificity, sensitivity, matrix effect, recovery and stability. The newly developed LC-MS/MS method was reliable to monitor doxorubicin concentrations in rabbit plasma.展开更多
A control system used in high performance liquid chromatograph(HPLC) was described.The control system adopting low pressure gradient elution was tested with different initial and end volume fractions,and four types of...A control system used in high performance liquid chromatograph(HPLC) was described.The control system adopting low pressure gradient elution was tested with different initial and end volume fractions,and four types of gradient elution curves.The experimental results verified the theoretical analyses of the applied method.This self-designed control system can achieve approving accuracy,repeatability and low cost,which has a bright outlook for domestic applications.展开更多
文摘目的为实现绞股蓝总皂苷(Gynostemma pentaphyllum saponins,GPS)色谱洗脱过程实时监测,保障纯化过程绞股蓝总皂苷质量一致性。方法采集色谱洗脱过程7批共计237个样本的拉曼光谱,将其中5批用于建模,2批用于外部测试,以总皂苷质量浓度、总固体量和人参皂苷Rb_(3)(Rb_(3))质量浓度为指标,采用高斯过程回归(Gaussian process regression,GPR)法建立定量模型,并将GPR模型与偏最小二乘回归及支持向量机回归定量模型进行性能对比。结果基于拉曼光谱技术结合GPR,建立了其洗脱过程的多指标定量校正模型。总皂苷质量浓度、总固体量和Rb_(3)质量浓度3个指标的GPR模型均具有更高的决定系数(R2),训练集R2均为1.00,验证集R2分别为0.953、0.986、0.939,以及更低的误差均方根(root mean square error,RMSE),训练集RMSE分别为70.4、224.0、31.6μg/mL,验证集RMSE分别为3.02、2.03、1.19 mg/mL。GPR模型在外部测试集的结果为总皂苷质量浓度、总固体量和Rb_(3)质量浓度预测R2分别达到0.947、0.954、0.837,RMSE分别为3.28、4.37、2.44 mg/mL;GPR模型能较好地反映总皂苷质量浓度和总固体量含量和变化趋势,但对Rb_(3)质量浓度的预测能力较弱。结论以总皂苷质量浓度和总固体量为指标,提出的基于拉曼光谱结合GPR建模的方法可实现绞股蓝总皂苷色谱洗脱过程的实时监测。
文摘The conventional protein chromatography technique was adopted to purify the antifreeze proteins (AFPs) from the leaves of Ammopiptanthus mongolicus (Maxim.) Cheng f. Two bands on native PAGE gel showed thermal hysteresis activity, one was band B1, whose thermal hysteresis was 0.46 ℃ at 8 g/L, which showed two bands (67 kD, 21 kD) on SDS_PAGE gel; the other was B3, whose thermal hysteresis was 0.45 ℃ at 10 g/L, and it contained only a single protein (39.8 kD). Both B1 and B3 are not glycoproteins, because neither do they interact with Shiff_reagent, nor show ultraviolet characteristics of a typical glycoprotein.
文摘The determination of synthetic phenolic antioxidants （SPAs） including propyl gallate （PG）, tertiary butyl hydroquinone （TI3HQ）, butylated hydroxyanisole （BHA） and butylated hydroxytoluene （BHT） in food items is reported using high performance liquid chromatography （HPLC）. A Cls column is used as the stationary phase, acetonltrile and water：Acetic acid （1%） is used as the mobile phase of gradient elution and the UV detec- tor is set at 280 nm. Under the above conditions, four antioxidents is completely separated within 8 rain. The limit of detection, linear range, and reproducibility of HPLC are evaluated. Isolation parameters of SPAs from different types of food items （cooking oil, margarine and butter, and cheese） are optimized. SPAs are extracted from food items through extraction with methanol/acetonitrile （1 ： 1, in volume）, vortex, ultrasonic treatment and precipitation in a freezer （2 h）. For cooking oil margarine, butter and cheese at 50 and 200 rag/L, recoveries of SPAs are 93.3%0--108.3% （PG）, 85.3~^--108.3~~ （TBHQ）, 96.7~^--101.2~/6 （BHA）, and 73.9^-- 94.6% （BHT）. The method is applied to the determination of SPAs in 38 food items （16 cooking oils, 8 mar- garine, 6 butter and 6 cheese samples）. The levels of SPAs in positive samples are all below the legal limits of China.
基金National Natural Science Foundation of China（ Grant No.81571779）.
文摘In the present study, we developed and validated a simple and sensitive gradient elution liquid chromatography tandem mass spectrometry （LC-MS/MS） method for quantification of doxorubicin in rabbit plasma. Daunorubicin was used as an internal standard （IS）. The doxorubicin and IS were extracted with ethyl acetate from plasma samples. The chromatographic separations were achieved on a C18 column （2.1 mm×50 mm, 2.5μm） configured with a C18 guard column （2.1 mm×10 mm, 2.5 μm）. The mobile phase of 0.1% formic acid-water solution and acetonitrile was delivered using a gradient elution program at a flow rate of 0.4 mL/min. The temperature for column was maintained at 40 ℃. The electrospray ionization （ESI） source was operated in the positive ion mode, and the quantification was conducted using multiple reaction monitoring （MRM） of the transitions m/z 544.07→396.96 and m/z 528.06→321.05 for doxorubicin and IS, respectively. The calibration curve of doxorubicin was linear （r 〉 0.999） within the range of 2-600 ng/mL. The lower limit of quantification was 2 ng/mL. The relative errors of intra-day and inter-day accuracies ranged from -2.48% to 0.18% and from -3.78% to 1.94%, respectively. The relative standard deviations of intra-day and inter-day precisions were less than 8.65% and 6.41%, respectively. The method exhibited satisfactory results in terms of specificity, sensitivity, matrix effect, recovery and stability. The newly developed LC-MS/MS method was reliable to monitor doxorubicin concentrations in rabbit plasma.
基金the National High Technology Research and Development Program (863) of China(No. 2009AA04Z326)the National Natural Science Foundation of China (Nos. 60671059, 60871091 and60588101)+1 种基金the National Basic Research Program (973) of China (Nos. 2005CB724302 and 2005CB724303)the 111 Project from the Ministry of Education of China(No. B08020)
文摘A control system used in high performance liquid chromatograph(HPLC) was described.The control system adopting low pressure gradient elution was tested with different initial and end volume fractions,and four types of gradient elution curves.The experimental results verified the theoretical analyses of the applied method.This self-designed control system can achieve approving accuracy,repeatability and low cost,which has a bright outlook for domestic applications.
