Of fritted glassware

Lead Oxide. The more common lead oxides are litharge (PbO, m.p. 886°C) and red lead or minium (Pb304). These oxides are important constituents of heavy glassware, enamels, and some pottery glazes because the oxides are poisonous, it is normal (in the UK compulsory) to form an insoluble lead silicate frit and to employ this non-toxic material as a source of lead for ceramic glazes. 

Caution. The residues on the glassware and the frit may contain sodium-potassium alloy and/or tris(trimethylsilyl)arsine and should not be exposed to air until disposal. tert-Butyl alcohol and isopropyl alcohol can be used to destroy these pyrophoric compounds however, this should be performed in a fume hood, as arsine gas may be generated. The solid on the frit can be mixed with class D metal fire extinguisher and subsequently treated with either of the aforementioned alcohols. 

You can make a liquid-membrane ion-selective electrode with glassware and chemicals available in most laboratories. All you need are a pH meter, a pair of reference electrodes, a fritted-glass filter crucible or tube, trimethylchlorosilane, and a liquid-ion exchanger. 

Ti(CO)6] are often obtained when 18-crown-6 is purified by other methods. Naphthalene is sublimed in vacuum. THF is distilled from purple disodium benzophenone and other solvents are purged with nitrogen gas and purified by standard procedures. Unless otherwise stated, solid reagents are transferred in an inert gas-fiUed dry box. Glassware and filter aid (i.e., diatomaceous earth or Kieselguhr) are dried at about 160°C for 12h before use. Medium-porosity Schlenk frits have a nominal maximum pore size of 10-15 pm and are equivalent to analogous porosity 3 units. 

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