Microwave digestion of organic substances, a useful tool for dissolved organic nitrogen measurements

According to Valderrama (1981) aquatic samples are successfully digested wi th peroxodisulphate prior to total nitrogen determination. This study compa res the utilization of a microwave oven and an autoclave for the preparatio n of liquid samples in terms of precision and accuracy of the obtained reco very. The comparison encompasses both reference solutions such as urea, ami no acids, nucleic acids and recalcitrant compounds as well as natural water samples. Although the observed differences are small, the microwave digest ion technique proofs significantly more precise. On the other hand, biases introduced by each of the techniques are similar. The slightly but signific antly better precision and its easy utilization on board research vessels m ake the microwave digestion technique highly recommendable. (C) 1998 Elsevi er Science Ltd. All rights reserved.