• Restorative Dentistry and Endodontics
• /
• v.47 no.1
• /
• pp.8.1-8.9
• /
• 2022

Objectives: The aim of this study was to compare the color change of the Giomer resin composite (Beautifil-Bulk) by using photographs obtained with a smartphone (iPhone 6S) associated with Adobe Photoshop software (digital method), with the spectrophotometric method (Vita Easyshade) after immersion in different pigment solutions. Materials and Methods: Twenty resin composite samples with a diameter of 15.0 mm and thickness of 1.0 mm were confectioned in A2 color (n = 5). Photographs and initial color readings were performed with a smartphone and spectrophotometer, respectively. Then, samples were randomly divided and subjected to cycles of immersion in distilled water (control), açai, Coke, and tomato sauce, 3 times a day, 20 minutes for 7 days. Later, new photographs and color readings were taken. Results: The analysis (2-way analysis of variance, Holm-Sidak, p < 0.05) demonstrated no statistical difference (p < 0.005) between the methods in all groups. Similar color changes were observed for all pigment solutions when using the spectrophotometric method. For the digital method, all color changes were clinically unacceptable, with distilled water and tomato sauce similar to each other and with statistical differences (p < 0.005) for Coke and açai. Conclusions: Only the tomato sauce produced a color change above the acceptability threshold using both methods of color assessment. The spectrophotometric and digital methods produce different patterns of color change. According to our results, the spectrophotometric method is more recommended in color change assessment.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.6
• /
• pp.863-868
• /
• 2006

The partial least squares (PLS-1) calibration model based on spectrophotometric measurement, for the simultaneous determination of sulfite and sulfide is described. This method is based on the difference between the rate of the reaction of sulfide and sulfite with Malachite Green in pH 7.0 buffer solution and at 25 ${^{\circ}C}$. The absorption kinetic profiles of the solutions were monitored by measuring the decrease in the absorbance of Malachite Green at 617 nm in the time range 10-180 s after initiation of the reactions with 2 s intervals. The experimental calibration matrix for partial least squares (PLS-1) calibration was designed with 24 samples. The cross-validation method was used for selecting the number of factors. The results showed that simultaneous determination could be performed in the range 0.030-1.5 and 0.030-1.2 $\mu$g m$L ^{-1}$ for sulfite and sulfide, respectively. The proposed method was successfully applied to simultaneous determination of sulfite and sulfide in water samples and whole human blood.

• Korean Journal of Pharmacognosy
• /
• v.33 no.3 s.130
• /
• pp.182-186
• /
• 2002

The Coptidis rhizoma is known for containing protoberberine alkaloids. Berberine, coptisine and palmatine are the major constituents of protoberberine alkaloids. The alkaloids were isolated and determined by forming complex compounds from Coptidis rhizoma in preparation I(Sam-Hwang-Sa-Sim-Tang) and II(Hwang-Ryen-Tang). For the determination of these alkaloids, a new spectrophotometric method was developed with a simple and selective sample clean-up using thiocyanatocobaltate[II] complex compound ion. The absorbance of alkaloidal complex compounds in l.2-dichloroethane solution was measured at 625 nm. Calibration curve for the alkaloids isolated from Coptidis rhizoma was linear over the concentration range of 0.2-0.3 mg/ml. The method was proved to be rapid, simple and reliable for the isolation and the determination of the alkaloids in Coptidis rhizoma preparation I and II.

• YAKHAK HOEJI
• /
• v.28 no.2
• /
• pp.61-67
• /
• 1984

A method is described for the spectrophotometric determination of platinum (IV) with 2-oximino-1-indanone based on solvent extraction of Pt:2-oximino-1-indanone complex. The 2-oximino-1-indanone reacted with Pt(IV) to form a dark-orange complex which shows a characterisic maximum absorption at 342nm. The optimum PH for the platinum extraction lies between 5.4~8.0. Beer's law obeys up to 0.98-16.3ppm of platinum (IV) and the molar absorption coefficient is $1.06{\times}10^{-4}L.mol^{-1}.cm^{-1}$. The relative standard deviation of the method was $\times2.1%$. The composition of the complex is estimated to be Pt : In= 1 : 1, by the mole ratio method and ion exchange resin experiment. The optimum condition for the determination of platinum has been studied in detail. The 2-oximin-1-indanone is found to be a selectivereagent for the determination of platinum, since the synthesixed 2-oximino-1-indanone did not react with other metals such as cobalt, cadmium, copper, manganese nickel, iron, lead and zinc, to form the complex. In this studies, we have also clarified Sindhwani and Singh's spectrophotometric determination data of various metals with acenaphthenequinone monooxime (Talanta 20,248, 1973), whose results were not correct.

• YAKHAK HOEJI
• /
• v.34 no.1
• /
• pp.22-33
• /
• 1990

Aqueous solution of bis(2,4-diaminophenyl)phosphonate(APP) was very stable, especially below pH 2.0 and the red-color compound formed by the reaction of APP and $IO_3-$ was stable at room temperature. A simple and rapid spectrophotometric method for the determination of ascorbic acid, potassium antimonyl tartrate (PAT), and isonicotinic acid hydrazide (INAH) was established by the reaction of $IO_3-$ and these reducing drugs, and the absorbance measurements were made at 500 nm. In the reaction of $IO_3-$ and each of the reducing drugs, the conditions of pH were suitable below 2.5 for ascorbic acid, below 2.0 for PAT, and below 1.5 for INAH. Beer's law did hold in the range of $17.6{\sim}1549.9\;ug$ for ascorbic acid, $33.4{\sim}2871.8{\mu}g$ for PAT,and $6.9{\sim}548.6\;{\mu}g$ for INAH. Many common ingredients present in pharmaceutical dosage forms did not interfere. The average recoveries for ascorbic acid and INAH in pharmaceutical formulations were 99.8 $-100.3\;{\pm}\;0.2{\sim}0.4%$, $99.8\;{\pm}\;0.3%$, respectively.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.8
• /
• pp.1137-1142
• /
• 2004

A spectrophotometric and first derivative spectrophotometric method was developed in aquatic Tween 80 micellar solutions for selective determination of nickel without using any pre-separation step. 1-(2-Pyridylazo)-2-naphthol (PAN), as a sensitive chromogenic complexing agent formed a red-colored Ni(II)-PAN complex in Tween 80 media with satisfactory solubility and stability. Conditions such as pH, PAN concentration, type and concentration of micellizing agent were optimized. Molar absorptivity of Ni-PAN complex was found $4.62\;{\times}\;10^4L\;cm^{?1}\;mol^{?1}$ at 569 nm, under the optimum condition. Calibration graphs were derived by zero, first and second derivative spectrophotometry at maximum wavelengths of 569, 578 and 571 nm with linear ranges of 30-1800, 20-2500 and 30-2000 ng $mL^{?1}$ , respectively. Precision as standard deviation as well as accuracy as recovery percent were in the range of 1-20 ng $mL^{?1}$, and 93.3-103.3%, respectively, for the entire of the linear ranges. Spectrophotometric detection limit was 3 ng $mL^{?1}$ and effects of diverse ions on the first derivative determination of nickel were studied to investigate selectivity of the method. Interferences of cobalt and copper on the nickel determination were prevented using o-phenanthroline as masking agent. The recommended procedures were applied to the various synthetic and stainless steel alloys, tea leaves and human hair, with satisfactory results.

• Analytical Science and Technology
• /
• v.13 no.1
• /
• pp.22-26
• /
• 2000

2-Hydroxybenzaldehyde-5-Nitro-pyridylhydrazone (2HB-5NPH) was synthesized and its application in the spectrophotometric determination of vanadium ion(IV) was studied in the presence of surfactant. The optimum conditions of pH, solvent effect, concentration of ligand and surfactant were evaluated. The procedure was applied to determination of vanadium (IV) in mixture sample and real sample with satisfactory results (recovery ${\geq}$ 97% ; relative standard deviation ${\leq}$ 3.0% in the concentration range of $0{\sim}1.5{\mu}g/mL$ ; detection limit, $0.02{\mu}g/mL$ in solution).

• Bulletin of the Korean Chemical Society
• /
• v.14 no.1
• /
• pp.59-62
• /
• 1993

Spectrophotometric determination of some heavy lanthanide ions by flow injection method is described. Xylenol Orange forms water soluble chelates with lanthanide ions in a tris[hydroxymethyl]-aminomethane-buffered medium having pH 8.3 and containing cetyltrimethylammonium bromide. The molar absorptivities of Ln(III)-XO complexes were increased by the ternary system with cetyltrimethylammonium bromide with the concomitant bathochromic shift of absorption maxium compared to those of the binary system without cetyltrimethylammonium bromide. The calibration curves are linear in the range 0.25-1.00 ppm for Gd(III), Dy(III), Er(III), Tm(III) and Yb(III) and the dynamic range are very wide. The detection limits (S/N=2) are from 2 ppb for Gd(III) to 30 ppb for Yb(III) and the relative standard deviations are from 1.2% for 0.5 ppm Gd(III) to 1.8% for 0.5 ppm Yb(III). The sample throughput was ca. 50 $h^{-1}$.

• 월간산업보건
• /
• s.49
• /
• pp.4-10
• /
• 1992

• Bulletin of the Korean Chemical Society
• /
• v.25 no.1
• /
• pp.127-129
• /
• 2004