Simplex optimization: A tutorial approach and recent applications in analytical chemistry

Bezerra, Marcos Almeida; Santos, Queila O. dos; Santos, Aldenor Gomes; Novaes, Cléber Galvão; Ferreira, Sérgio Luís Costa; Souza, Valdinei Santos de

doi:10.1016/j.microc.2015.07.023

Cited by 64 publications

(34 citation statements)

References 40 publications

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“…In this sense, the optimization of the extraction of phenolic compounds is essential to reach an accurate analysis, and this process has been traditionally performed using the one-variable-at-a-time method (OVATM). However, this technique does not allow assessing the effects of interactions between variables (Bezerra et al, 2016 ). In the last years, multivariate chemometric tools such as Response Surface Methodology (RSM) are useful for optimizing specific compound extraction (Novaes et al, 2017 ).…”

Section: Introductionmentioning

confidence: 99%

Mixture Design and Doehlert Matrix for the Optimization of the Extraction of Phenolic Compounds from Spondias mombin L Apple Bagasse Agroindustrial Residues

et al. 2018

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In this study, we have determined, using RSM (mixture design and Doehlert matrix), the optimum values of the independent variables to achieve the maximum response for the extraction of total phenolic compounds from Spondias mombin L bagasse agroindustrial residues in order to preserve their antioxidant activity. The extraction of phenolic compounds, as well as their antioxidant capacity and the capacity to scavenge ABTS, was determined by the modified DPPH method at different periods of time, temperature, velocity of rotation and solvents concentration. We observed that the optimum condition for the highest antioxidant yield was obtained using water (60.84%), acetone (30.31%), and ethanol (8.85%) at 30 • C during 20 min at 50 rpm. We have also found that the maximum yield of total phenolics was 355.63 ± 9.77 (mg GAE/100 g), showing an EC 50 of 3,962.24 ± 41.20 (g fruit/g of DPPH) and 8.36 ± 0.30 (µM trolox/g fruit), which were measured using DPPH and ABTS assays. These results suggest that RSM was successfully applied for optimizing the extraction of phenolics compounds thus preserving their antioxidant activity.

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Section: Introductionmentioning

confidence: 99%

Mixture Design and Doehlert Matrix for the Optimization of the Extraction of Phenolic Compounds from Spondias mombin L Apple Bagasse Agroindustrial Residues

et al. 2018

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“…To obtain the best analytical response, univariate and multivariate approaches were used [6,20]. Initially, the optimizations were performed with UP water fortified with 100 µg L −1 of each analyte in glass vials with capacity of 22 mL.…”

Section: Optimization Procedures Using Baµementioning

confidence: 99%

Application of bar adsorptive microextraction (BAµE) for the determination of pesticides and emerging contaminants in water used for rice cultivation in southern Brazil

et al. 2020

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Brazil is among the ten largest rice producers in the world, concentrating its production in the southern region. Anthropic activities, such as the disposal of chemicals in the ecosystem and consequently in the aquatic environment, end up harming the availability and quality of the water. Here, we developed an analytical method based on BAµE with WAX as an extraction phase for the determination of 5 pesticides and 2 emerging contaminants in water samples used in rice cultivation by HPLC-DAD. The method was fully optimized through univariate and multivariate approaches. The optimized condition was obtained with 145 min of extraction time, without salt addition and 35 min of desorption time using 250 μL of MeOH:AcEt (60:40, v/v). A reduced mass of extraction phase (around 4 mg) and sample and solvent volumes (15 mL and 300 µL, respectively) were used. The bars have a low cost and can be used up to 20 times without loss of extraction efficiency. Furthermore, the developed method presented high-throughput, because it uses a Voltage Regulator Variac system that allows the coupling of six magnetic stirrers simultaneously. The LODs ranged from 1.67 to 2.50 µg L −1 and the LOQs ranged from 5.00 to 7.50 µg L −1 ; both were below the VMP established by Ordinance 2.914/2011/MS for drinking water. Relative recoveries applied to the sample ranged from 80 to 121%. The intra-day and inter-day precision were up to 14% and 19%, respectively. The results were satisfactory, in accordance with the validation guidelines of the AOAC. Twenty-four samples collected in the Camboriú River Basin, which is influenced by rhiziculture, were analyzed and the analytes were not detected, as they are below the limits obtained in this method.

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“…Among these, the two-level full factorial is the most used one, even though it preliminarily evaluates the effects of the factors on the processes. This approach provides linear models [22][23][24][25]. Response surface methodologies (RSM) are multivariate optimization techniques, which allow for the finding of the critical conditions of the factors (maxima or minima) through the establishment of quadratic models [26].…”

Section: Introductionmentioning

confidence: 99%

Multivariate optimization of a procedure employing microwave-assisted digestion for the determination of nickel and vanadium in crude oil by ICP OES

Anjos

Alves

Soares

et al. 2018

Talanta

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This work presents the optimization of a sample preparation procedure using microwave-assisted digestion for the determination of nickel and vanadium in crude oil employing inductively coupled plasma optical emission spectrometry (ICP OES). The optimization step was performed utilizing a two-level full factorial design involving the following factors: concentrated nitric acid and hydrogen peroxide volumes, and microwave-assisted digestion temperature. Nickel and vanadium concentrations were used as responses. Additionally, a multiple response based on the normalization of the concentrations by the highest values was built to establish a compromise condition between the two analytes. A Doehlert matrix optimized the instrumental conditions of the ICP OE spectrometer. In this design, the plasma robustness was used as chemometric response. The experiments were performed using a digested oil sample solution doped with magnesium(II) ions, as well as a standard magnesium solution. The optimized method allows for the determination of nickel and vanadium with quantification limits of 0.79 and 0.20μgg, respectively, for a digested sample mass of 0.1g. The precision (expressed as relative standard deviations) was determined using five replicates of two oil samples and the results obtained were 1.63% and 3.67% for nickel and 0.42% and 4.64% for vanadium. Bismuth and yttrium were also tested as internal standards, and the results demonstrate that yttrium allows for a better precision for the method. The accuracy was confirmed by the analysis of the certified reference material trace element in fuel oil (CRM NIST 1634c). The proposed method was applied for the determination of nickel and vanadium in five crude oil samples from Brazilian Basins. The metal concentrations found varied from 7.30 to 33.21μgg for nickel and from 0.63 to 19.42μgg for vanadium.

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Simplex optimization: A tutorial approach and recent applications in analytical chemistry

Cited by 64 publications

References 40 publications

Mixture Design and Doehlert Matrix for the Optimization of the Extraction of Phenolic Compounds from Spondias mombin L Apple Bagasse Agroindustrial Residues

Mixture Design and Doehlert Matrix for the Optimization of the Extraction of Phenolic Compounds from Spondias mombin L Apple Bagasse Agroindustrial Residues

Application of bar adsorptive microextraction (BAµE) for the determination of pesticides and emerging contaminants in water used for rice cultivation in southern Brazil

Multivariate optimization of a procedure employing microwave-assisted digestion for the determination of nickel and vanadium in crude oil by ICP OES

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