原子荧光法测定大气PM_(2.5)中重金属的条件试验研究

对原子荧光法测定大气PM2.5中汞、砷、硒等重金属元素的条件进行了研究。研究得出最佳采样滤膜材质为石英纤维滤膜;样品在前处理完成后还原剂硫脲的加入使测定方法更准确;对电热板消解法、沸水浴法和微波消解法3种前处理方法进行比较试验,得出沸水浴法同时测定汞、砷、硒等5种重金属元素加标回收率最好,为94.5%~105.0%。该方法精密度较高,相对标准偏差在1.43%~4.70%,同时具有设备成本低的优点。     

石墨炉原子吸收分光光度法测定土壤中总铬

建立了土壤中总铬测定的石墨炉原子吸收分光光度法;以塞曼效应扣除背景,优化了石墨炉灰化、原子化温度、停留时间及基体改进剂用量。结果表明:当原子化温度为2 700℃,灰化温度为700℃,原子化时间2 s,灰化时间为9 s;基体改进剂用量为3~5μL时,仪器可以达到最佳工作状态。该方法铬元素浓度在0~32μg/L内呈良好的线性关系,相关系数r=0.999 9,检出限为0.3 mg/kg;对土壤标样GSS-1和ESS-1的铬测定精密度均小于5%,相对误差在-4.8%~-0.7%之间,方法的灵敏度和准确度均符合要求。因此,石墨炉原子吸收分光光度法测定土壤中总铬具有原子化温度高、干扰少、灵敏度高等特点可适用土壤中总铬的测定。     

Theoretical study on the degradation reaction of octachlorinated dibenzo-p-dioxin with atomic oxygen O(3P) in dielectric barrier discharge reactor

Dielectric barrier discharges （DBD） have been used in the degradation of dioxins due to the large number of excimers and free radicals produced in discharge process. In this article, the density functional theory （DFT） is used to study the degradation mechanism of octachlorinated dibenzo-p-dioxin （OCDD） with the atomic oxygen O（3P） in DBD reactor. The reactants, intermediates, transition states and products are optimized at the MPWB1K/6- 31 ＋ G（d,p） level. The vibrational frequencies have been calculated at the same level. The reaction pathways and mechanisms are analyzed in detail. The effect of removing the chlorine atom on environment also has been discussed.     

水中铅的测定——流动注射氢化物原子吸收光谱法

目前水质分析部门对测定水中铅一般采用双硫腙比色法和原子吸收光谱法这两种方法,但都需要萃取、分离富集等繁琐的操作手段,分析时间长,用样品量大,有机溶剂污染环境等弊端。本文采用流动注射、氢化物原子吸收测定铅,它具有分析速度快、灵敏度等优点,回收率在95%-102%。     

用CA-CN型微孔滤膜采集大气飘尘中痕量铅

以微孔滤膜采集大气飘尘样品,用石墨炉原子吸收法测定飘尘中痕量铅。精密度实验的变异系数为0.9％～2.7％;样品平均回收率为99.7％,微孔滤膜解吸回收率为90.5％～97.7％。     

原子荧光光谱法测定土壤中的汞

采用微波消解土壤并结合螯合树脂类SPE预处理柱去除消解液中重金属,原子荧光光谱法测定土壤中的汞。本方法前处理操作过程简单,用酸量少,避免了测定元素的挥发损失,汞加标回收率为92．8％-104．5％,方法准确度与精密度均令人满意。     

原子吸收法固体进样测定土壤中镉含量的不确定度评定

利用原子吸收法固体进样装置测定土壤中镉的含量,并对其测量过程进行了不确定度评定,从而明确了测定时的主要不确定度来源是曲线拟合过程,在测定过程中需进一步改进。     

纳米TiO_2固相萃取原子吸收光谱法测定工业废水中铅与镉

主要研究了纳米TiO2固相萃取与原子吸收光谱法测定工业废水中铅与镉的方法。合成了3种不同粒径的纳米TiO2,探讨了粒径对铅与镉离子分离富集效率的影响,发现其萃取效率随着粒径的增大而降低。在原子吸收光谱仪最佳操作条件下,工业废水样品中镉与铅的检出限分别为0.010和0.046μg/L。工业废水中铅与镉的分析结果表明,该方法具有灵敏度高、简便快速、相对误差较小等特点。     

Analysis of lead in tongkat Ali hitam herbal preparations in Malaysia

The DCA (Drug Control Authority), Ministry of Health, Malaysia implemented the phase three registration of traditional medicines on January 1st, 1992. As such, a total of 100 products in various pharmaceutical dosage forms of a herbal preparation obtained in Malaysia, containing tongkat Ali hitam, either single or combined preparations, were analyzed for the contamination of a heavy toxic metal, lead, using atomic absorption spectrophotometer, after performing a simple random sampling to enable each sample an equal chance of being selected in an unbiased manner. Results showed that 17% of these products contained 10.3–20.3?ppm of lead, and therefore, do not comply with the quality requirement for traditional medicines in Malaysia. The quality requirement for traditional medicines in Malaysia is not exceeding 10?ppm for lead. Out of these 17 products, 7 products have been registered with the DCA, Malaysia whilst the rest, however, have not registered with the DCA, Malaysia. Although this study showed that 83% of the products complied with the quality requirement for traditional medicines in Malaysia pertaining to lead, however, they cannot be assumed safe from lead contamination because of the risk of batch-to-batch variability.     

对YYG—2型冷原子荧光测汞仪的改进研究

我们通过对YYG-2型冷原子测汞仪荧光室和相应气路系统的改进,克服了原仪器在操作过程中汞蒸汽直接排于工作台面的现象,提高了仪器的稳定性能和灵敏度,减少了操作步骤和节省了载气,在不同程度上还减化了原仪器结构。通过实践证明改进后的仪器基本上满足了环境监测或其它测试分析的要求。