气溶胶样品中钋-210的分析方法探究

通过调研和实验建立了合适的分析气溶胶中210Po的方法,气溶胶样品经强酸处理,使210Po溶于溶液中,再利用电化学置换反应,将溶液中的210Po置换到银片表面,最后用α谱仪对银片进行测量。该方法的210Po全程回收率在75%左右,为研究大气中210Po的活度浓度提供了可靠的分析手段。

基于Fe(OH)3-CaCO3载带的水中^228Ra的γ能谱分析方法

建立了一种基于Fe(OH)3-CaCO3载带的水中^228Ra的γ能谱分析方法,适用于环境水中^228Ra的分析。采用Fe(OH)3-CaCO3共沉淀法富集水中的^228Ra,将富集后的^228Ra采用Ba(Ra)SO4共沉淀法进一步载带,133Ba示踪法确定^228Ra的全程回收率,使用高纯锗γ谱仪测量与^228Ra达到放射性平衡的衰变子体^228Ac的特征γ能量,从而获得^228Ra的分析结果。通过对5 L水样的加标验证可知,^228Ra回收率为81.8%~87.5%,加标水样测量结果与添加量的相对偏差为1.7%~5.3%,此方法的探测限为57.2 mBq/L。

基于氢氧化铁-碳酸钙载带的水中^(226)Ra的γ能谱分析方法

建立了一种基于氢氧化铁-碳酸钙载带水中^(226)Ra的γ能谱分析方法,适用于环境水中^(226)Ra分析。在计算公式中,采用样品粉末质量修正因子和方法回收率对测量结果进行修正。通过对20 L水样的加标验证,本方法加标样的回收率高于83.0%,各组加标样回收率的平均值高于90.9%,准确度范围为2.05%-12.7%,精确度范围为3.20%-5.38%。利用无源效率刻度软件计算探测效率来确定探测下限和样品使用量的关系,得出采样量为40-60 L时最佳,此时探测下限为2.0 mBq·L^(-1)左右。

利用高效液相色谱分析苯氧化制苯酚的产物组成

建立了一种利用高效液相色谱(HPLC)快速分析苯氧化制苯酚产物组成的方法。该方法采用XBridge C 18反相色谱柱(4.6 mm×150 mm×5μm),以0.1%(质量分数)的甲酸水溶液与乙腈为流动相,梯度洗脱方式,紫外吸收检测波长为210,245,275,290 nm,分析周期为10 min。标样的测试结果表明:各目标化合物在质量浓度为5~350 mg/L时呈现良好的线性响应,回归系数均大于0.999,最低检出限为0.006~0.120 mg/L;方法回收率在88.40%~103.40%,6次重复测定结果的相对标准偏差均小于3.00%。

RP-HPLC色谱法测定血浆中地西泮浓度

目的本文建立了血浆中地西泮浓度的HPLC快速测定方法。方法采用氯硝西泮为内标，流动相为甲醇-水（70:3O)，检测波长为254nm。结果地西泮浓度在0．05-15ug／ml范围内线性良好，最低检测浓度为10ng/ml回收率为98．2%-101．5％日内变异系数为0．9％-2．1%日间变异系数为1.3％-2．8％。结论该方法操作简便、快速、准确，灵敏度高，重现性好，适用于临床地西泮血药浓度的快速测定。

Comparative analysis of methods for concentrating venom from jellyfish Rhopilema esculentum Kishinouye

In this study, several methods were compared for the efficiency to concentrate venom from the tentacles of jellyfish Rhopilema esculentum Kishinouye. The results show that the methods using either freezing-dry or gel absorption to remove water to concentrate venom are not applicable due to the low concentration of the compounds dissolved. Although the recovery efficiency and the total venom obtained using the dialysis dehydration method are high, some proteins can be lost during the concentrating process. Comparing to the lyophilization method, ultrafiltration is a simple way to concentrate the compounds at high percentage but the hemolytic activities of the proteins obtained by ultrafiltration appear to be lower. Our results suggest that overall lyophilization is the best and recommended method to concentrate venom from the tentacles of jellyfish. It shows not only the high recovery efficiency for the venoms but high hemolytic activities as well.

Optimal control of cobalt crust seabedmining parameters based on simulated annealing genetic algorithm

Under the condition of the designated collection ratio and the interfused ratio of mullock, to ensure the least energy consumption, the parameters of collecting head （the feed speed, the axes height of collecting head, and the rotate speed） are chosen as the optimized parameters. According to the force on the cutting pick, the collecting size of the cobalt crust and bedrock and the optimized energy consumption of the collecting head, the optimized design model of collecting head is built. Taking two hundred groups seabed microtopography for grand in the range of depth displacement from 4.5 to 5.5 era, then making use of the improved simulated annealing genetic algorithm （SAGA）, the corresponding optimized result can be obtained. At the same time, in order to speed up the controlling of collecting head, the optimization results are analyzed using the regression analysis method, and the conclusion of the second parameter of the seabed microtopography is drawn.

Improved recovery of a low-grade refractory gold ore using flotation–preoxidation–cyanidation methods

In this work, different flotation–preoxidation–cyanidation methods are considered for treating a lowgrade refractory gold ore. On the one hand, the results of selective flotation show that 22% and 31.1%of total Sb and As, respectively, remained in the final tailings and only about 28% of the total Au remained for further cyanidation processes. On the other hand, in bulk method of flotation the maximum Au recovery of 90.6% achieved after 60 min of flotation at the grind size with K80 of 146 micron. In addition, the bulk flotation method resulted in the concentrate with low concentrations of Sb and As elements. To improve the recovery of low-grade refractory gold ores, flotation should be followed by roasting, biological, or pressure oxidation processes so that the gold could be liberated prior to cyanidation processes. It is also found that the pressure oxidation pre-treatment of the concentrates prior to cyanidation may yield high gold recoveries of over than 83%. In these processes, recoveries are controlled by the temperature and the oxygen partial pressure in the solvent. However, by utilizing the bio-oxidation technique, the oxidation of sulfur to sulfate cannot be completed and, consequently, the gold recovery may be limited to only 72.2%.

Optimization of Sample Pretreatment for Determination of Polycyclic Aromatic Hydrocarbons in Estuarine Sediments by Gas Chromatography

This study examined levels of polycyclic aromatic hydrocarbons (PAHs) in estuarine sediments in Licun (Qingdao, China) by gas chromatography under optimized conditions for sample pretreatment via ultrasonic extraction, column chromatography, and thin layer chromatography. Methanol and dichloromethane (DCM)/methanol (2:1, v/v) were used in ultrasonic extraction, and DCM was used as eluate for column chromatography. The developing system consisted of n-hexane and DCM at a ratio of 9:1 (v/v), with DCM as the extraction solvent for PAHs-containing silica gel scraped off the plate. When the spiking level is 100 ng, total recoveries of spiked matrices for four target PAHs (phenanthrene, anthracene, pyrene and chrysene) were 83.7%, 76.4%, 85.8%, and 88.7%, respectively, with relative standard deviation (RSD) between 5.0% and 6.5% (n = 4). When the spiking level is 1000 ng, associated total recoveries were 78.6%, 72.7%, 82.7% and 85.3%, respectively, with RSD between 4.4% and 5.3% (n = 4). The opti-mized method was advantageous for determination of PAHs in complex matrix due to its effective sample purification.