The combination of infrared and microwave radiation to quantify trace elements in organic samples by ICP OES

• Published in: Talanta (Oxford) Vol. 107; pp. 292 - 296
• Main Authors: Dantas, A.N.S., Matos, W.O., Gouveia, S.T., Lopes, G.S.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 30.03.2013
• Subjects: Aluminum; Animals; Copper; Equipment Design; Food Analysis - instrumentation; Food Analysis - methods; Humans; ICP OES; Inductively coupled plasma; Infrared radiation; Infrared Rays; Iron; Magnesium; Microwave-assisted digestion; Microwaves; Milk - chemistry; Sample preparation; Sensitivity and Specificity; Spectrophotometry, Atomic - methods; Standard reference materials; Trace Elements - analysis; ICP OES; Infrared radiation; Sample preparation; Microwave-assisted digestion
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2013.01.047

Sample-decomposition methods using microwave radiation in closed systems have been commonly used in the analysis of inorganic constituents; however, these methods are limited to small amounts of organic samples. This work proposes the combined use of infrared radiation and microwave radiation (IR-MW) to increase the amount of organic samples digested. The determination of Al, Ca, Cu, Fe, K, Mg, Mn, Na, P and Zn in human-feed samples was accomplished by ICP OES. The results were in agreement with those obtained from conventional decomposition by microwave radiation (closed system). The results obtained using the proposed IR-MW system for standard reference material (whole milk powder, NIST 8435) were also compared. Agreements of 85–100% were obtained for Al, Ca, Cu, Fe, K, Mg, Na, P and Zn in the standard reference material. The IR-MW system is simple to implement and cheap because it uses commercially available infrared lamps and allows the use of infrared radiation in the microwave-digestion vessel. Additionally, it is possible to reach better precision in the analysis of the human-feed samples using the IR-MW system. The proposed method also allows total digestion of large sample amounts or samples rich in organic compounds can also be performed in the IR-MW system using small volumes of nitric acid. ► Sample mass up to 1g was completely digested using the IR-MW system. ► The layout of IR-MW is a simple arrangement with a commercially-available IR lamp. ► The same quartz vessel from the MW oven is used in the IR lamp. ► The IR-MW is a promising alternative to digest organic samples for trace analysis.