scholarly journals Development of multivariate calibration method for simultaneous determination of nickel, lead and zinc in tap water

2015 ◽  
Vol 18 (2) ◽  
pp. 145-151
Author(s):  
Chau Minh Huynh ◽  
Thu Du Ly ◽  
Thach Thai Pham ◽  
Tran Thi Bao Pham ◽  
Minh Khanh Duong ◽  
...  

Conventional spectrophotometric methods for simultaneous determination of nickel, lead and zinc in forms of complexes with a reagent is not feasible due to the overlap of their absorption spectra. A multivariate calibration method was used to overcome this problem. In this study, the calibration model was constructed based on absorption spectra of 30 mixture standards in the range from 490 to 600 nm. Factors influencing experimental results such as amount of reagents, pH, and color development time were optimized. The standard calibration ranges for determination of nickel, lead and zinc were found at 0.5-5 ppm. The method was applied for determination of these ions in tap water samples at ppm level, with recoveries (and RSD) of nickel, lead and zinc were 103.3 % (3.0 %), 74.9 % (11.5 %) and 104.6 % (4.6 %), respectively.

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2497 ◽  
Author(s):  
José Luis Fernández ◽  
Felicia Sáez ◽  
Eulogio Castro ◽  
Paloma Manzanares ◽  
Mercedes Ballesteros ◽  
...  

The determination of chemical composition of lignocellulose biomass by wet chemistry analysis is labor-intensive, expensive, and time consuming. Near infrared (NIR) spectroscopy coupled with multivariate calibration offers a rapid and no-destructive alternative method. The objective of this work is to develop a NIR calibration model for olive tree lignocellulosic biomass as a rapid tool and alternative method for chemical characterization of olive tree pruning over current wet methods. In this study, 79 milled olive tree pruning samples were analyzed for extractives, lignin, cellulose, hemicellulose, and ash content. These samples were scanned by reflectance diffuse near infrared techniques and a predictive model based on partial least squares (PLS) multivariate calibration method was developed. Five parameters were calibrated: Lignin, cellulose, hemicellulose, ash, and extractives. NIR models obtained were able to predict main components composition with R2cv values over 0.5, except for lignin which showed lowest prediction accuracy.


2013 ◽  
Vol 785-786 ◽  
pp. 1353-1358 ◽  
Author(s):  
Chan Gai Deng ◽  
Li Fu Liao ◽  
Wei Long

A new potentiometric titration method coupled with multivariate calibration using a flow injection technique for the simultaneous determination of multi-components in alloy has been developed. the titrant is a mixture of EDTA and sodium fluoride, both mercury film electrode and fluorinion selective electrode are inserted in the flow cell. In a process of titration, both the potentiometric of mercury ion and the mixed proportion of reactants at each titration point can be obtained simultaneously from the two electrodes, and then the concentration of each component in the mixture can be obtained from the titration curves by multivariate calibration method. The method is free of volumetric and time measurements, and reduces the consumption of reagents and samples. The method is also very quick in analysis rapidity. The method has been applied for the simultaneous determination of copper, lead and zinc in alloy samples with the relative standard deviation of 0.18%~0.45% and the recovery of 99.5%~101.6%.


2013 ◽  
Vol 78 (4) ◽  
pp. 555-564 ◽  
Author(s):  
Hadi Givianrad ◽  
Mohammad Saber-Tehrani ◽  
Saber Zarin

The simultaneous determination of sulfamethoxazole (SMX) and trimethoprim (TMP) mixtures in bovine milk by spectrophotometric method is a difficult problem in analytical chemistry, due to spectral interferences. By means of multivariate calibration methods, such as partial least square (PLS) regression, it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range. Genetic algorithm (GA) is a suitable method for selecting wavelengths for PLS calibration of mixtures with almost identical spectra without loss of prediction capacity using the spectrophotometric method. In this study, the calibration model based on absorption spectra in the 200-400 nm range for 25 different mixtures of SMX and TMP Calibration matrices were formed form samples containing 0.25-20 and 0.3-21 ?g mL-1 for SMX and TMP, at pH=10, respectively. The root mean squared error of deviation (RMSED) for SMX and TMP with PLS and genetic algorithm partial least square (GAPLS) were 0.242, 0.066 ?gmL-1 and 0.074, 0.027 ?g mL-1, respectively. This procedure was allowed the simultaneous determination of SMX and TMP in synthetic and real samples and good reliability of the determination was proved.


Chemosensors ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 88
Author(s):  
Samuel Piña ◽  
Christian Candia-Onfray ◽  
Natalia Hassan ◽  
Paola Jara-Ulloa ◽  
David Contreras ◽  
...  

The simultaneous determination of hydroquinone and catechol was conducted in aqueous and real samples by means of differential pulse voltammetry (DPV) using a glassy carbon electrode modified with Gold Nanoparticles (AuNP) and functionalized multiwalled carbon nanotubes by drop coating. A good response was obtained in the simultaneous determination of both isomers through standard addition to samples prepared with analytical grade water and multivariate calibration by partial least squares (PLS) in winery wastewater fortified with HQ and CT from 4.0 to 150.00 µM. A sensitivity of 0.154 µA µM−1 and 0.107 µA µM−1, and detection limits of 4.3 and 3.9 µM were found for hydroquinone and catechol, respectively. We verified the reliability of the developed method by simultaneously screening analytes in spiked tap water and industrial wastewater, achieving recoveries over 80%. In addition, this paper demonstrates the applicability of chemometric tools for the simultaneous quantification of both isomers in real matrices, obtaining prediction errors of lower than 10% in fortified wastewater.


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