Heath A B, Black R R
NSW Department of Agriculture, Board of Tick Control, Laboratory, Lismore, NSW, Australia.
J Assoc Off Anal Chem. 1987 Sep-Oct;70(5):862-5.
A new assisted distillation tube has been developed which contains no glass beads or glass wool. The sample is injected into the top of the tube, and a septum is not required. Large ground-glass joints (10/19) are used at the gas inlet and at the Florisil trap connection for maximum strength. Existing assisted distillation apparatus was easily modified to accept the new tubes. Recoveries of 9 organochlorine pesticides from butter and cattle fat ranged from 87 to 104% at a tube temperature of 230 degrees C and a nitrogen flow rate of 250 mL/min. No significant change occurred in recoveries of 8 of the 9 pesticides after 85 uses of the beadless tube. Only the recovery of HCB from butter decreased, from 95 to 80%, after 51 runs. The new tube was compared with the Unitrex glass bead-packed concentric tube at flow rates of 230, 400, and 600 mL nitrogen/min. Recoveries from the Unitrex tube were similar to those of the beadless tube for all pesticides except DDT which was significantly lower, indicating incomplete distillation at 250 mL/min and possible partial breakdown at 400 and 600 mL/min. A procedure is introduced for pressurized solvent washing of distillation tubes. This procedure is more efficient than vacuum washing.
已研发出一种新型辅助蒸馏管，其不含玻璃珠或玻璃棉。样品注入管顶部，无需使用隔垫。气体入口处和弗罗里硅土捕集阱连接处使用大型磨口玻璃接头（10/19），以确保最大强度。现有的辅助蒸馏装置可轻松改装以适配新管。在管温度为230℃、氮气流速为250毫升/分钟的条件下，从黄油和牛脂中回收9种有机氯农药的回收率在87%至104%之间。无玻璃珠管使用85次后，9种农药中有8种的回收率无显著变化。仅在运行51次后，黄油中六氯苯的回收率从95%降至80%。将新管与Unitrex玻璃珠填充同心管在氮气流速为230、400和600毫升/分钟的条件下进行了比较。除滴滴涕外，Unitrex管对所有农药的回收率与无玻璃珠管相似，滴滴涕的回收率显著较低，表明在250毫升/分钟时蒸馏不完全，在400和600毫升/分钟时可能部分分解。介绍了一种蒸馏管加压溶剂清洗程序。该程序比真空清洗更有效。
