Determination of PAH, PCB, and OCP in water from the Three Gorges Reservoir accumulated by semipermeable membrane devices (SPMD)

Bioavailable water concentrations of polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB) and organochlorine pesticides (OCP) were measured in the water column from Three Gorges Reservoir (TGR) collected in May 2008 using semipermeable membrane devices (SPMDs). The sampling sites spanned the whole reservoir from the upstream Chongqing to the great dam covering more than 600 km long distance with water flow velocities ranging from <0.05 to 1.5 m s(-1). This is the first experience of SPMD application in the biggest reservoir in the world. The results of water sampling rates based on performance reference compounds (PRC) were tested to be significantly correlated with water flow velocities in the big river. Results of back-calculated aqueous concentrations based on PRC showed obvious regional variations of PAH, PCB and OCP levels in the reservoir. Total PAH ranged from 13.8 to 97.2 ng L-1, with the higher concentrations occurring in the region of upstream and near the dam. Phenanthrene, fluoranthene, pyrene and chrysene were the predominant PAH compounds in TGR water. Total PCB ranged from 0.08 to 0.51 ng L-1, with the highest one occurring in the region near the dam. PCB 28, 52, 101, 138, 153, 180, 118 were the most abundant PCB congeners in the water. The total OCP ranged from 2.33 to 3.60 ng L-1 and the levels showed homogenous distribution in the whole reservoir. HCH, DDT and HCB, PeCB were the major compounds of OCP fingerprints. Based on water quality criteria, the TGR water could be designated as being polluted by HCB and PAH. Data on PAH, PCB and OCP concentrations found in this survey can be used as reference levels for future POP monitoring programmes in TGR. (C) 2009 Elsevier Ltd. All rights reserved.

实现微电极阵列与PCB电路柔性连接的方法

本发明公开了一种实现微电极阵列与PCB电路柔性连接的方法，该方法包括:制作PCB接口板;将弹簧针插座焊接在该PCB接口板上，并将弹簧针针体插在插座上构成弹性针床;将弹簧针针体的头部对准微电极阵列接口电极，通过紧固螺丝压缩弹簧针，将弹簧针针体的头部与电极形成接触连接;将弹簧针插座端的引线与电生理信号放大器和刺激器进行连接，引线端与中心部分微电极一一对应，实现微电极阵列和外围电路的电气连接。本发明缩短了微电极阵列接口板的制作周期，节约了制作成本，针床与电极接触良好而不磨损电极表面金属层，电极的导电性能不受影响，延长了微电极阵列寿命。