The microwave-induced combustion (MIC) technique wasapplied
for coal digestion and
further determination o
fbromide, chloride,
fluoride, and iodide by ion chromatography (IC). Samples (up to 500 mg) were combustedat 2 MPa o
f oxygen. Combustion was complete in less than50 s, and analytes were absorbed in water or (NH
4)
2CO
3solution. A re
flux step was applied to improve analyteabsorption. Accuracy was evaluated
for Br, Cl, and F usingcerti
fied re
ference coal and spiked samples
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 o
f re
flux. With the use o
f the same conditions, therecoveries
for I were better than 97%. Br, Cl, and I werealso determined in MIC digests by inductively coupledplasma mass spectrometry, inductively coupled plasmaoptical emission spectrometry, and F was determined byan ion-selective electrode with agreement better than 95%to the values obtained using IC. Temperature duringcombustion was higher than 1350
![](/images/entities/deg.gi<font color=)
f">C, and the residualcarbon content was lower than 1%. With the use o
f theMIC technique, up to eight samples could be processedsimultaneously, and a single absorbing solution wassuitable
for all analytes and determination techniques(limit o
f detection by IC was better than 3
![](/images/entities/mgr.gi<font color=)
f">g g
-1 for allhalogens).