A simple alarm to aid in preparative glpc fraction collection

the necessity of keeping one's eye and mind on the recorder during glpc purifica- tions. Such an alarm can be inexpensively constructed from a. batter...
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A Simple Alarm to Aid in Preparative GLPC Fraction Collection

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lournol o f Chemical Education

A simple alarm which can be adjusted to "sound off" when the recorder pen of a preparative gas chromatograph reaches a preset height above the base line eliminates the necessity of keeping one's eye and mind on the recorder during glpc purifications. Such an alarm can be inexpensively constructed from a. battery powered bicycle horn. One switch wire from the horn is attached to the recorder pen carriage by means of a n alligator clip, with a portion of uninsulated wire exposed. The second lead from the horn is attached t o the recorder hodv a t a oosition such that an uninsulated portion of this lead will tonch the pen carriage iead when the pen is a t a predetermined level above the base line. Leads prepared as illustrated below are easy to adjust and attach to the recorder