170135_inorganicventures_flipping

5:4 Container Material Proper8es

Quartz: (cont.)

• Use the synthe)c type III quartz whenever possible. • More details as to the contamina)on issues around the use of quartz will be discussed later. • Quartz is typically 99.8+% SiO2. • It is aEacked by HF, boiling H3PO4, and the alkali and alkaline earth oxides, hydroxides, and carbonates. • It can be heated to 1100 ̍C . • Its main advantage over that of porcelain is that major contamina)on occurs from only Si --however, this contamina)on can be significant.

5:5 Container Material Properties

Pla$num :

• It heats up and cools down rapidly, making it excellent for % ash determina;ons where the % ash is at low levels. • It is resistant to a>ack by most acids and reagents. Avoid concentrated H3PO4 at high temperatures, HCl + HNO3 mixtures and fusions using Li2CO3, Na2O2, or the alkali hydroxides. • Fusions using Na2CO3 are common in addi;on to fusions using the alkali borates, fluorides, nitrates, and bisulphates. Avoid hea;ng at prolonged temperatures in excess of 1100 ̍C (m.p. = 1772 ̍C). • Pla;num can be destroyed by hea;ng with metals with which it can alloy. Avoid high temperature hea;ng with samples containing significant levels of any metal that may be in or reduced to the metallic state during the hea;ng process.(All precious metals, Cu, Hg, Sn,) • Pla;num is known to contain trace amounts of the other precious metals and should not be used for their prepara;on. • Avoid ashing samples containing P in any form, including the phosphates.