Use of Mixture Design with Minimal Restrictions to Optimize an Extraction Procedure Employing Diluted Acids Assisted by Ultrasound and Microwave for Nutrient Element Determination in Vegetal Samples

Abstract

In this work, it was developed an alternative analytical strategy for the preparation of vegetal samples extracted with diluted acids and assisted by ultrasound and microwave radiation for the determination of nutrients elements by fast sequential flame atomic absorption spectrometer. The conditions optimized using univariate and multivariate methodologies for the procedure were as follows: 200 mg of sample; extraction solution comprising a mixture of 6.3 mL HNO 3 , 2.1 mL HCl, and 1.7 mL CH 3 COOH; extractor with a final concentration of 2.5 mol L −1 ; a sonication time of 30 min; and a microwave radiation time of 6 s. The accuracy of the procedure was confirmed by analyzing the certified reference material NIST 1515 (apple leaves) and by comparison with the results obtained through microwave-assisted total digestion method. The procedure was applied to determine Ca, Mg, Cu, Mn, Fe, and Zn in several cassava peel samples used in animal nutrition, and proved to be simple, reliable, fast, easy to implement, and inexpensive.

Applications of mixture experiments for response surface methodology implementation in analytical methods development

“…The publications using mixture experimental regards the analysis of food, [16][17][18][19] drugs, [20][21][22][23][24][25] biological samples, [26][27][28][29] fingerprints, 10,30-32 among others. [33][34][35][36][37] The literature searches reveals that there are many situations where mixture experiments are applicable, being the great majority of these works related to the sample preparation procedure 10,17,19,[30][31][32]35,36 or to the liquid chromatography mobile phase optimization. 10,20,21,25,27,29,31,38 Most of the mixture experiments requires a single simplex design to optimize one or multiple responses of the studied system.…”

Ultrasound-Assisted Extraction of Micro- and Macroelements in Fruit Peel Powder Mineral Supplement for Osteoporosis Patients and Their Determination by Flame Atomic Absorption Spectrometry

“…High pressure and temperature along with a large volume of reagents (acids and hydrogen peroxide) are required for getting adequate results by using these digestion methods [22][23][24]. Ultrasoundassisted extraction (UAE) is a promisingly alternative method to microwave-assisted digestion or conventional acid digestion methods to get adequate results and enough potential for extracting metals in different food matrices, sediments [25], and animal and plant tissues [26,27] where ultrasonic energy is used to make the process of extraction in the presence of matrix analyte easier.…”