Silica frits, microporous

Version (b) has a four-channel flow guidance that encompasses two mixing tees in two simple mixing tees (Figure 4.5) [8]. An example of this function is the flow guidance for the Michael addition. In a first step, the base and 1,3-dicarbonyl compound streams merge. The enolate stream thus formed is then mixed with the Michael acceptor. Microporous silica frits are set into the channels to minimize... 

Watts and Haswell have demonstrated dipeptide and tripeptide synthesis, as the first example of EOF-based multistep synthesis, in a borosilicate glass microfluidic channel, as shown in Fig. 2. A T-shaped microreactor with 200pLmx50pLm channels was fabricated the overall reactor dimensions were 20 mm x 20 mm x 25 mm. The channels were filled with microporous silica frit to reduce hydrodynamic effects. After deprotection with one equivalent of hydrazine, tripeptide synthesis was also demonstrated. An offline high-pressure liquid chromatograph (HPLC) was used to determine the results of the synthesis. 

If you reconnect the column and start the pump and the pressure persists, then you need to remove the outlet end frit in the same way. (Remember the white packing on the shoes ) Outlet pressure is due to fines in the column collecting in this filter usually only a problem if you are using the original irregular-shaped microporous columns. Sonicating with 10% sodium hydroxide can clean them since they are silica. Wash the base out repeatedly with water, replace the frit, and run the column. 

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