Kazi T G, Jamali M K, Siddiqui A, Kazi G H, Arain M B, Afridi H I
National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080, Pakistan.
Chemosphere. 2006 Apr;63(3):411-20. doi: 10.1016/j.chemosphere.2005.08.056. Epub 2005 Nov 15.
A rapid ultrasound accelerated sequential extraction procedure has been used to develop sequential extraction proposed by BCR protocol (the community Bureau of Reference now the European Union "Measurement and Testing Programme"). The effects of the ultrasonic treatment on the extraction of Cu, Cd, Cr, Pb, Ni and Zn from untreated sewage sludge collected from industrial site of Hyderabad city (Pakistan) were compared with those obtained from conventional sequentional extraction procedure of modified BCR protocol. In BCR method, each extraction steps takes 10h, where as with the use of compromise sonication conditions in ultrasonic bath, steps 1-3 of the sequential extraction (excluding the hydrogen peroxide digestion in step 3, which was not performed with sonication) could be completed in 30, 30 and 30 min, respectively. Extractable Cd, Cr, Pb and Ni contents were obtained by both comparable methodologies were measured by electrothermal atomic absorption spectrometry (ETAAS), while for Cu and Zn Flame atomic absorption spectrometry (FAAS) was used. The validations of both methods were compared by the analysis of certified reference material of soil amended with sewage sludge (BCR 483). According to statistical evaluation of the results, the proposed accelerated extraction method is valid alternative to conventional shaking with much shorter extraction time with p value <0.05. The overall metal recoveries in steps 1-3 (excluding residual step) were 95-100% of those obtained with the conventional BCR protocol, except for Cu extracted (91.6%) as related to indicative values of Cu in BCR 483 obtained in 1-3 steps. The results of the partitioning study of untreated industrial waste water sewage sludge, indicate that more easily mobilized forms (acid exchangeable) were predominant for Cd and Zn, in contrast, the largest amount of Pb and Cr was associated with the iron/manganese oxide and organic matter/sulphide fractions.
一种快速超声加速连续萃取程序已被用于开发由BCR协议（现欧盟“测量与测试计划”的参考物质与测量研究所）提出的连续萃取方法。将超声处理对从巴基斯坦海得拉巴德市工业场地收集的未处理污水污泥中铜、镉、铬、铅、镍和锌萃取的影响，与改良BCR协议的传统连续萃取程序所获得的影响进行了比较。在BCR方法中，每个萃取步骤需要10小时，而在超声浴中使用折中的超声处理条件时，连续萃取步骤中的第1 - 3步（不包括第3步中用过氧化氢消解，该步骤不进行超声处理）分别可在30分钟、30分钟和30分钟内完成。两种可比方法获得的可萃取镉、铬、铅和镍含量通过电热原子吸收光谱法（ETAAS）测量，而对于铜和锌则使用火焰原子吸收光谱法（FAAS）。通过分析用污水污泥改良的土壤标准物质（BCR 483）对两种方法的有效性进行了比较。根据结果的统计评估，所提出的加速萃取方法是传统振荡法的有效替代方法，萃取时间短得多，p值<0.05。步骤1 - 3（不包括残留步骤）中的总金属回收率是传统BCR协议获得的回收率的95 - 100%，但第1 - 3步中萃取的铜（91.6%）与BCR 483中铜的指示值相关。未处理的工业废水污水污泥的分配研究结果表明，镉和锌以更易迁移的形态（酸可交换态）为主，相反，铅和铬的最大含量与铁/锰氧化物和有机质/硫化物组分相关。
