Fast and simple flow-batch extraction procedure for screening of macro and micronutrients in dried plant leaves by ICP OES

Acid extraction is an alternative procedure for sample preparation for determination of macro and micronutrients in plant tissues. This approach presents as advantages its speed, simplicity, low cost and use of diluted acid solutions in mild conditions (temperature and pressure). However, most of the extraction procedures are performed in batch mode, which makes them more laborious, time-consuming and susceptible to errors when compared to procedures in flow and flow-batch mode. In this work, the performance of a flow-batch extraction system for on-line determination of macro and micronutrients in dried plant leaves by ICP OES was evaluated. The proposed flow-batch system is simple for operation, inexpensive, allowed on-line determination of macro and micronutrients in dried plant leaves by ICP OES and could be easily applied in any routine analysis laboratory. The best efficiency extraction was achieved using 50 mg of dried spinach leaves, 10 mL of 8% V V− 1 HCl and 4 min of extraction time. Despite applying 4 min of extraction time, it is important to highlight that some elements, such as Cu, K, Mg, Mn and Na, can be extracted in as short as 30 s extraction times. The flow-batch system presented good accuracy and most elements determined in CRMs and samples are in good agreement with certified values and concentrations determined after microwave-assisted acid digestion, respectively.