Microwave-assisted digestion with a single reaction chamber for mineral fertilizer analysis by inductively coupled plasma optical emission spectrometry

ABSTRACT

A systematic approach is proposed to evaluate microwave-assisted digestion in a single reaction chamber for the simultaneous determination of elements in the mineral fertilizer and raw material by inductively coupled plasma optical emission spectrometry. A reference material was digested using 12 acid mixtures containing nitric, hydrochloric, orthophosphoric, hydrofluoric or boric acid. Principal components analysis was applied for data treatment. Three digestion procedures based on diluted acids exhibited the most accurate results, with relative errors for reference values ranging from −15% to + 9%. Limits of quantification were in the range of 0.2 mg cadmium kg⁻¹ up to 1000 mg aluminum kg^−1.

KEYWORDS:

• Diluted acids
• inductively coupled plasma
• microwave
• mineral fertilizer
• sample preparation

Additional information

Funding

The authors are grateful to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundação de Amparo à Pesquisa do Estado de São Paulo for financial support. The authors express their gratitude to Lanagro for providing samples and to Anacom Científica/Milestone and Nova Analítica/Thermo Scientific for making equipment available to use.