On-Line Microwave Sample Pretreatment for Organic and Inorganic Analyte Determination by Instrumental Techniques: A Review

Background: Microwave energy has been used in chemistry for years. Regarding analytical chemistry, microwave energy has been employed for extraction, digestion, reaction, fractionation and speciation of selected analytes from several matrix samples. Within this goal, automation has of concern in these applications. Methods: This review presents some applications of microwave use in flow systems for the determination of selected inorganic and organic analytes from several types of samples. A literature survey was done with the aim to identify relevant applications of the use of microwave energy in flow systems. Results: Application of on-line microwave sample-preparation techniques, based on coupling a microwave unit with extraction, reaction, digestion, speciation, or fractionation, were selected from the current literature describing instrumental techniques and detection. The versatility of closed and open microwave systems as well on-line configurations for static and dynamic are presented. Conclusion: The aim of this paper is to review the most important literature describing the application of microwave radiation in analytical chemistry using on-line coupling with modern instrumental measurement techniques. This review is not intended to be exhaustive, but describes relevant applications of on-line microwave sample pretreatment.