MI
7An Apparatus for Washing NMR Tubes The small g l ~ rusn i t shown in the accompanying illustration, is most convenient for cleaning, rinsing, and drying eight stmdard size nmr tubes simultaneouslv. The tubes to he cleaned are inverted carefully over each of the 2.5-mm 0.d. outlet tubes, and approximately 10 ml of the appropriate cleaning solutions or solvents are poured in turn (e.g., fuming nitric acid, water, alcohol, chloroform, and carbon tetrachloride) into the reservoir and allowed to flow out slowly through the nmr tubes. The d e sign of the apparatus is such that the liquids passed through the system in this way will syphon out almost completely. Drying of the tuhes can be effected ouicklv and convenientlv without ~
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viously very susceptible t o breakage. In practice tiowever, its utility was found ta be more than compensation for the little extra care required in its use. Alternstely, a more rohr\& model can be constructed from stainless steel if one i3 able to avoid the use of strong oxidizing acids for cleaning purposes.
Volume 47, Number 7, July 1970
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