The BEAC4ND4 ionophore has been successfully synthesized from p-t-butylcalix[4]arene carboxylic acid. The BEAC4ND4 ionophore was obtained in two steps of the synthesis reaction. The first step is the chlorination reaction of p-t-butylcalix[4]arene carboxylic acid with thionyl chloride in dry benzene solvent. The chlorination reaction product is p-t-butylcalix[4]arene acyl chloride in the form of the light brown viscous liquid with a yield of 78.25% and TLC (SiO2, CH3OH: CH2Cl2 = 1: 1 v/v, Rf = 0.65). The second step is the amidation reaction of ethyl 2-aminoacetate with p-t-butylcalix[4]arene acyl chloride in dry tetrahydrofuran solvent. The product of the amidation reaction is p-t-butylcalix[4]arene ethylesteramide or the BEAC4ND4 ionophore in the form of a white solid with the yield of 75.22%, a melting point of 314-316°C, and TLC (SiO2, CH3OH: CH2Cl2 = 1: 1 v/v, Rf = 0.75).
<p>The research on the highly selective and sensitive determination of Hg(II) ions using ion-selective electrodes (ISE) coated with the BEC4ND1 ionophore as a membrane has been successfully carried out. ISE was designed using the membrane composition of the [(BEC4ND1 ionophore : PTCPB : DOS : PVC) (3 : 2 : 60 : 35 % w/w)]. The ESI-BEC4ND1 ionophore has good characteristics where it shows a sensitivity value of 29.933 mV/decade in the Hg(II) ion concentration range of 10<sup>-9</sup> - 10<sup>-1</sup> M with a limit of detection (LoD) of 10<sup>-7</sup> M. The response time obtained is in the range of 4 - 8 minutes with a relative standard deviation (RSD) of 0.548. The ESI-BEC4ND1 ionophore also shows the average value of selectivity coefficient (K<sub>ij</sub>) < 1. These results indicate that the presence of Zn(II), Cd(II), and Pb(II) ions as interfering ions in the analyte solution does not affect the performance of the ESI-BEC4ND1 ionophore in detecting Hg(II) ions. The ESI-BEC4ND1 ionophore that has been developed shows good selectivity, sensitivity, stability, and reproducibility, so the ESI-BEC4ND1 ionophore is promising to be used as a Hg(II) ion detector in the environment.</p>
Research on the extraction of chemical components of Dengen (Dillenia serrata Thumb) leaves using the MAE (microwave-assisted extraction) method and activity as an antioxidant and toxicity test has been carried out. This study aimed to extract the chemical components of Dengen leaves using the MAE method and to test the antioxidant activity and toxicity of the ethanol extract of Dengen leaves. The chemical components of Dengen leaves were extracted by the MAE method and obtained ethanol extract with a yield of 47%. Dengen leaves ethanol extract was partitioned with n-hexane and ethanol as solvents and obtained yields of 5% (n-hexane) and 65% (ethanol). The chemical components of Dengen leave ethanol extract were identified by phytochemical screening. The results of phytochemical screening showed the presence of secondary metabolites of alkaloids, flavonoids, saponins, polyphenols, terpenoids, and steroids. The antioxidant activity test of the ethanol extract of Dengen leaves was carried out using the DPPH (2,2-diphenyl-1-picrihydrazil) method and obtained the value of IC50 = 100,363 ppm (strong antioxidant). A toxicity test of the ethanol extract of Dengen leaves was carried out using the BSLT (Brine Shrimp Lethality Test) method and obtained the value of LC50 = 18.3443 ppm (very toxic).
Heavy metal concentration exceeding the threshold amount is hazardous to the environment, so it needs some treatment. The study aimed to know the capacity and kinetics of adsorption. This study used the adsorption method to remove the heavy metal ion Ni(II) using persimmon tannin gel. Influences of time contact, pH, and ion concentration in the adsorption process were also investigated. Results showed optimum adsorption at 60 minutes of time contact and pH 5. Variation of concentration made the adsorption decrease as metal ion Ni(II) concentration increased. The maximum adsorption capacity was 23.14 mg/g by using pseudo-second-order adsorption kinetic model.
Synthesis of glucopyranosyl acetic from sago flour as raw material for the synthetic polymers has been successfully carried out. The synthesis product is obtained through two reaction stages, namely the hydrolysis and esterification reactions. Sago flour is hydrolyzed with 25% HCl and neutralized with 45% NaOH. Glucose hydrolysis of sago starch and acetic anhydride was esterified using a zinc chloride catalyst. Synthesis product was obtained as a white solid substance (57.31% recovery), a melting point of 110 - 111oC, and Rf 0.79 on TLC (SiO2, n-hexane: ethyl acetate = 9:1 v/v). The results of the analysis of synthesis products with FTIR and GC-MS spectrometers showed that the synthesis product was glucopyranosyl acetic or 2,3,4,6-tetra-O-acetyl glucopyranose.
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