A rapid and practical method for direct detection of lisinopril in anion exchange chromatography（AEC） has been developed with integrated pulsed amperometric detection（IPAD）.Dionex AS 18（250 mm×2 mm） and AG 18（50 mm×2 mm） columns and 40 mmol/L NaOH solution were used for separation.Multi-step potential waveform parameters were optimized to maximize the signal-to-noise ratio（S/N）.Utilizing the optimized waveform,the repeatability（intra-day） precision and intermediate（inter-day） precision were obtained with relative standard deviation（RSD） of 0.74,0.93,respectively.The limit of quantification（LOQ） and limit of detection（LOD） were found to be 0.37,0.12ng/mL,respectively,with the correlation coefficient of 0.9998 over concentration range 0.01-1μg/mL.The present method was successfully applied to the determination of lisinopril in human plasma.The recoveries of plasma sample spiked by 0.2μg/mL,0.8μg/mL lisinopril were 98.31-103.23%with RSD of 1.41%, 0.61%,respectively.
Yu Xiu LiuDan ShouMei Lan ChenZhi Dong ChenPei Min ZhangYan Zhu
An ion chromatography（IC） system coupled with on-line column-switching technique was used to determine anions ofμg/g levels in organic chemicals of analytical reagent grade.A novel polystyrene-divinylbenzene-carbon nanotube（PS-DVB-CNT） stationary phase was utilized for matrix elimination.A calibration study was conducted by preparing and analyzing eight concentrations（between 10 and 5000μg/L） of eight standards in deionized water.The linearity was between 0.9978 and 1.And the detection limits ranged from 1.54μg/L to 10.02μg/L.A spiking study was performed on two representative organic chemicals.The recoveries were between 84.3%and 119.6%.
Ying Ying ZhongWen Fang ZhouXue Ling ZengMing Li YeYan Zhu
A new and simple method was developed to determine anions in oxalate of analytical reagent grade. After UV photolysis with optimal 1% H2O2 in 10,000 mg/L oxalate in the fabricated photoreactor, sample was directly injected into IC system. Satisfactory linearity, detections limits, good repeatability and spiked recovery were obtained. The method was successfully applied to determine anions in two commercial oxalate samples.
Sheng Lin CaoMing Li YeWei De LvGuang Wen PanTing Ting ZhangZhong Yang HuLi Na LiangYan Zhu
An ion chromatography method has been proposed for the determination of three common inorganic anions（chloride,nitrate and sulfate） in anionic surfactants using a single pump system.The new system consists of an ion exclusion column,a concentrator column,and an anion exchange column connected in series via two 6-ports valves in a Dionex ICS-2000 ion chromatograph.The valves were switched several times for removing surfactants,concentrating and separating the three anions.The chromatographic conditions were optimized.Detection limits（S/N = 3） were in the range of 0.10-0.68μg/L.The relative standard deviations（RSDs） of peak area were less than 4.6%.The recoveries were in the range of 84.1-112.6%.
A new method was developed for simultaneous determination of levels of AMP,ADP and ATP in blood by anion-exchange chromatography.The three adenosine phosphates were separated by Dionex IonPac AG18（50 mm×4 mm） guard column and IonPac AS 18（250 mm×4 mm） analytical column using a gradient method and detected with a suppressed conductivity detector. The detection limits（S/N=3） of AMP,ADP and ATP were 38,47,108 ng/L,respectively.The relative standard deviations of retention time,peak area and peak height were all less than 1.87%and a good linear relationship was obtained.This method was applied to analyze human blood samples.
Pei Jin XieMing Li YeZhong Yang HuGuang Wen PanYan ZhuJia Jie Zhang
