Preliminary Evaluation of Gunshot Residue (GSR) Using 3-Aminophenol as a Substitute in Modified Griess Test

In forensic ballistics, gunshot residue (GSR) particles can be detected using screening or presumptive tests which are mainly focused on the chromophoric reaction. Most tests serve as an initial indication for a forensic investigator at the crime scene before instrumental analysis for definitive identification. The screening methods are known to be convenient, have fast analysis, and minimal preparation. In GSR analysis, the well-known method of detecting GSR known as the Modified Griess Test (MGT) requires acid and heat for the reaction. Therefore, this study demonstrated a new and rapid screening test named the Rapid Griess Test (RGT) for the detection of GSR. This study intends to improve the functionality of previous screening reagents in determining nitrite (NO2–), the composition present after shooting activity. To do this, chemical reagents with an amino group, 3-aminophenol, were substituted with alpha-naphthol. The experiment showed that the reactions were positive color changes using standard NO2– and real GSR samples. The diazotization reactions involving sulfanilic acid and 3-aminophenol produced azo dyes that changed the solution from colorless to orange in the presence of NO2–. The RGT reagent will make it possible to avoid using heat and the addition of acetic acids in a sample to form chromophoric reactions. Moreover, the colorimetric method using Video Spectral Comparator (VSC) showed that RGT had higher intensity of the orange color when compared to MGT.

Sesquiterpenoids from the Stem Bark of Aglaia simplicifolia and Their Cytotoxic Activity against B16-F10 Melanoma Skin Cancer Cell

Four sesquiterpenoid derivatives, i.e., 4β,10α-dihydroxyaromadendrane (1), caryophyllenol-II (2), senecrassidiol (3), and clovane-2β,9α-diol (4) have been isolated from the stem bark of Aglaia simplicifolia. The chemical structures of compounds 1-4 were determined based on spectroscopic data, including one and two-dimensional NMR and mass spectroscopy. In addition, these sesquiterpenoids 1-4, were also tested for their cytotoxic activity against B16-F10 melanoma skin cancer cell lines through in vitro assay. Among the isolated compounds 1-4, compound 1 showed the highest activity with an IC50 value of 44.8 μg/mL, suggesting the presence of a cyclopropane ring that plays an essential role in cytotoxic activity against B16-F10 melanoma skin cancer cell lines.

Synthesis, Spectroscopic, and Photophysical Studies of Phosphorescent Bis(2-(2,4-difluorophenyl)pyridine)Iridium(III) Complex Containing Derivative of 1H-1,2,4-Triazole Anchillary Ligand

A cationic complex of iridium(III), [Ir(2,4-F2ppy)2(F2bpyta)]PF6 utilizing 1,2,4-triazolepyridyl as an anchillary ligand modified with a 2,6-difluorobenzyl substituent was synthesized and characterized. The aromatic signals of pyridyltriazole and phenylpyridine proton were detected in the 1H-NMR spectrum between 10.00 and 7.00 ppm. Only one singlet peak was detected at 8.46 ppm H(8) shifted to the upfield, demonstrating that C5 was coordinated to the central iridium metal. The bands exhibited in the range of 1555–1431 cm–1 in the IR spectrum because of the C=C and C=N aromatic rings stretching pyridine, phenyl, and triazole vibrations. The UV-Vis absorption spectrum showed a slight and broad absorbance peak at lower energy at a lmax = 371 nm (e = 6129 M−1 cm−1) in the visible range due to 1MLCT and 3MLCT transitions. Blue emission was observed in the steady-state emission spectral of [Ir(2,4-F2ppy)2(F2bpyta)]PF6 and the other two previously synthesized iridium(III) complexes in CH2Cl2 solutions (air-equilibrated) at room temperature. The spectrum of luminescence for the [Ir(2,4-F2ppy)2(F2bpyta)]PF6 (lem = 461 nm) is blue-shifted when compared to the [Ir(2,4-F2ppy)2(hpyta)]PF6 (lem = 469 nm), but red-shifted when related to the [Ir(2,4-F2ppy)2(mbpyta)]PF6 (lem = 454 nm).

Utilization of Corn Oil through Water Degumming Process for Lecithin Emulsifier Production

Lecithin is an emulsifier that plays an active role in reducing surface tension in making emulsions. The production of lecithin from other vegetable oils allows the use of other types of vegetable oil as a source of lecithin production to replace soy-based oil, which has begun to be used as a bioenergy raw material. This study aims to find an alternative source of new lecithin derived from corn oil by knowing the characteristics of lecithin and applied to mayonnaise. The resulting lecithin was used in mayonnaise with a 2 factorial randomized block design method consisting of 3 levels. Based on the results obtained, the characteristic of corn oil lecithin is that the largest content is hexadecanoic acid which is 44.79%, and the strongest vibration band is CH2 vibration with stretching modes of symmetry and asymmetry at 2922 and 2853 cm–1 and the terminal CH3 group in the 1374 cm–1. L3C3 treatment was the best result with 60% fat content, 4% emulsion stability, 2.12 cP viscosity, and 1.42 × 10–3 N/m surface tension and organoleptic showed a preference value, namely color 4.4 (like), taste 3.2 (sufficient like), smell 4 (like), and texture 3.80 (like it).

An Electrochemical Aptasensor for the Detection of HER2 as a Breast Cancer Biomarker Based on Gold Nanoparticles-Aptamer Bioconjugates

Inaccurate diagnoses contributes to the high mortality rate of breast cancer. Human epidermal growth factor receptor 2 (HER2) is overexpressed in breast cancer tumors at around 20–30%. This study aims to develop an electrochemical biosensor for HER2 based on a gold nanoparticle-aptamer bioconjugate (AuNP@HER2 aptamer) and investigate the interaction between DNA aptamer and HER2 using computational methods. The bioconjugate was synthesized using maleimide and polyethylene glycol as a linker. The –NH2 group of cysteamine that modified the gold electrode can form a covalent bond with the bioconjugate maleimide. The interaction of the bioconjugated aptamer with HER2 was measured electrochemically based on the [Fe(CN)6]3−/4− redox system. The limit of detection, the linear range of HER2, precision, and accuracy in this study were 1.52 ng mL–1, 0.01 to 15.0 ng mL–1, 0.1298, and 94.06%, respectively. The structure of the DNA aptamer was modeled using mFold, Assemble2, and Chimera, with the interaction between the DNA aptamer and HER2 explored by NPDock. The modeling of the aptamer with HER2 showed that electrostatic interactions dominated the attractive forces. The resulting interaction pattern can be used as a template to improve the binding energy of the aptamer, thus providing insight into the development of aptamer-based biosensors.

Ferrate(VI) Synthesis Using Fe(OH)3 from Waste Iron Electrolysis and Its Application for the Removal of Metal Ions and Anions in Water

Ferrate(VI) salt is an effective oxidant and coagulant for water treatment and removal of metal ions. This study demonstrates a new approach to processing metal ions and anions in water by Fe(VI) through Fe(III) obtained from the electrolysis of waste iron transformer. The electrolysis was successfully carried out in the Na2SO4 electrolyte using waste iron and zinc plates as anode and cathode, respectively. Fe(III) electrolysis results through the characterization of FTIR and XRD indicate compliance with Fe(OH)3 standards. Synthesis of ferrate was carried out by adding Fe(III) from electrolysis with NaOCl in alkaline conditions. The formed ferrate solution shows a purple color with a typical maximum wavelength of 505 nm. Furthermore, the ferrate obtained is used to remove metal ions (Fe(III), Cu(II), Zn(II), Mg(II), Pb(II)) and anions (sulfate, nitrate, and carbonate) in water with pH variations. Ferrate treatment filtrate was analyzed using AAS for metal ions, while sulfate, nitrate, and carbonate anions used UV-Vis spectrophotometry, turbidimetry, and titration methods. The results showed that ferrate effectively eliminates metal ions and anions in water with optimum pH 6. The mechanism of heavy metal removal by ferrate(VI) can be explained by ionic bonding and adsorption.

Synthesis of Symmetrical Acetophenone Azine Derivatives as Colorimetric and Fluorescent Cyanide Chemosensors

Cyanide is a highly toxic anion and poison to the environment. Therefore, fast, effective, and efficient analysis methods to detect cyanide are needed. Herein, symmetrical chemosensor of 2’-hydroxy acetophenone azine (1) and 2’,4’-dihydroxy acetophenone azine (2) has been synthesized tested as colorimetric and fluorescent cyanide chemosensor. The azines were produced from the condensation of acetophenone derivatives with hydrazine hydrate in ethanol under reflux or ultrasonic irradiation methods. Colorimetric and fluorescent chemosensor tests showed selectivity to acetate and cyanide anions in DMSO. The limit of detection (LOD) for colorimetric measurement of cyanide anion was 9.68×10–4 M for compound (1) and 9.63×10–5 M for compound (2), while the fluorescent method showed 15.90×10–4 M for compound (1) and 8.95×10–5 M for compound (2), respectively. In addition, test paper-strips containing sensor 2 indicated noticeable results for 'naked eye' detection of cyanide in an aqueous medium.

Modification of Fishbone-Based Hydroxyapatite with MnFe2O4 for Efficient Adsorption of Cd(II) and Ni(II) from Aqueous Solution

Due to their toxicity, Cd(II) and Ni(II) ions in the environment are severe. The hydroxyapatite composite was improved with magnetic MnFe2O4 to remove Cd(II) and Ni(II) ions from an aqueous solution. Hydroxyapatite was extracted from Snakehead (Channa striata) fish bones via alkaline-heat treatment. The hydroxyapatite/MnFe2O4 composite performance was analyzed through XRD, FTIR, SEM-EDS, BET analysis, and VSM, and the results reveal that the hydroxyapatite/MnFe2O4 composite shows good magnetic properties of 21.95 emu/g. The kinetics evaluation confirmed that the pseudo-second-order kinetics model was more suitable to describe the adsorption of Cd(II) and Ni(II) ions by hydroxyapatite/MnFe2O4 composite from the solution. The Langmuir isotherm model was suitable to describe the adsorption process of the Cd(II) and Ni(II) ions, where the adsorption capacities for Cd(II) and Ni(II) are 54.3 and 47.4 mg/g, respectively. Desorption of Cd(II) and Ni(II) ions from hydroxyapatite/MnFe2O4 composite using NaCl as the eluent was more effective than EDTA. The findings of this study indicate that hydroxyapatite/MnFe2O4 can reduce Cd(II) and Ni(II) ions in wastewater so that it can recover natural resources.

Computational Evaluation of Intermolecular Interaction in Poly(Styrene-Maleic Acid)-Water Complexes Using Density Functional Theory

The high application of Poly(styrene-maleic acid) (PSMA) in an aqueous environment, such as biomedical purposes, makes the interaction between PSMA and water molecules interesting to be investigated. This study evaluated the conformation, the hydrogen bond network, and the stabilities of all the possible intermolecular interactions between PSMA with water (PSMA−(H2O)n, n = 1–5). All calculations were executed using the density functional theory (DFT) method at B3LYP functional and the 6–311G** basis set. The energy interaction of PSMA–(H2O)5 complex was –56.66 kcal/mol, which is classified as high hydrogen bond interaction. The Highest Occupied Molecular Orbital (HOMO) – Lowest Unoccupied Molecular Orbital (LUMO) energy gap decreased with the rise in the number of H2O molecules, representing a more reactive complex. The strongest hydrogen bonding in PSMA–(H2O)5 wasformed through the interaction on O72···O17–H49 with stabilizing energy of 50.32 kcal/mol, that analyzed by natural bond orbital (NBO) theory. The quantum theory atoms in molecules (QTAIM) analysis showed that the hydrogen bonding (EHB) value on O72···O17–H49 was –14.95 kcal/mol. All computational data revealed that PSMA had moderate to high interaction with water molecules that indicated the water molecules were easily transported and kept in the PSMA matrix.

Preparation of Biodegradable and Low-Cost Lignin-Based PVOH Carbon Fibers Prepared by Electrospinning

A polyvinyl alcohol (PVOH)/lignin nanofiber was prepared by the electrospinning method as a precursor for biodegradable and low-cost carbon fibers. PVOH 15% was dissolved in water, and various concentration of lignin (5, 10, 15, 20, and 25%) was added. The presence of lignin in PVOH solution increased the viscosity and conductivity. From SEM analysis, PVOH solution produced smooth fiber, whereas the addition of lignin produced fibers in bead forms. The presence of lignin above 20% in PVOH did not produce spun-fiber. FTIR analysis confirmed that lignin was able to form hydrogen bonds with PVOH. TGA analysis showed that PVOH/lignin nanofibers had the highest residual mass, i.e., 40% at 600 °C. The morphology of the carbon fibers showed flake forms with many pores and had 58.07% carbon content.