| 摘要 |
For testing the lead content in it, a water sample of substantial volume is forced through a waterpermeable receiver, preferably of fibrous filamentary cellulose such as cotton or rayon, to extract lead from the test sample and trap it in concentrated form in the receiver. The receiver is dewatered and treated with a color-developing indicator, preferably rhodizonic acid dipotassium salt activated by an acidic buffer solution to a pH of approximately 2.8, which buffer solution preferably includes sodium bitartrate, resulting in the development of a red stain indicating the presence of lead. The potency of the rhodizonic salt in a liquid carrier can be extended by utilizing an alcohol preservative in water in approximately equal proportions. The foregoing process can be performed by a test kit having a syringe for forcing the water sample through a detachable spout packed with fibrous cellulose and such kit includes color-developing indicating liquid and buffer for application to the packed spout after its removal from the syringe.
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