The microwave-induced combustion (MIC) technique wasa
pplied for coal digestion and further determination ofbromide, chloride, fluoride, and iodide by ion chromatogra
phy (IC). Sam
ples (u
p to 500 mg) were combustedat 2 MPa of oxygen. Combustion was com
plete in less than50 s, and analytes were absorbed in water or (NH
4)
2CO
3solution. A reflux ste
p was a
pplied to im
prove analyteabsor
ption. Accuracy was evaluated for Br, Cl, and F usingcertified reference coal and s
piked sam
ples for I. For Br,Cl, and F, the agreement was between 96 and 103% using50 mmol L
-1 (NH
4)
2CO
3 as the absorbing solution and 5min of reflux. With the use of the same conditions, therecoveries for I were better than 97%. Br, Cl, and I werealso determined in MIC digests by inductively cou
pled
plasma mass s
pectrometry, inductively cou
pled
plasmao
ptical emission s
pectrometry, and F was determined byan ion-selective electrode with agreement better than 95%to the values obtained using IC. Tem
perature duringcombustion was higher than 1350
![](/images/entities/deg.gif)
C, and the residualcarbon content was lower than 1%. With the use of theMIC technique, u
p to eight sam
ples could be
processedsimultaneously, and a single absorbing solution wassuitable for all analytes and determination techniques(limit of detection by IC was better than 3
![](/images/entities/mgr.gif)
g g
-1 for allhalogens).