• Analytical Science and Technology
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• v.15 no.4
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• pp.335-340
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• 2002

An analytical method has been developed to determine multi-elements in human hair samples by inductively coupled plasma mass spectrometry (ICP-MS). 0.05 g of hair sample was added to the Teflon digestion bomb together with 1.5 mL of nitric acid and an appropriate amount of In as an internal standard. The sample was then decomposed in the microwave digestion system. The hair certified reference material, GBW 09101, was analyzed for the validation of the analytical method. The determined values were in good agreement with the certified values within the uncertainty range.

• Analytical Science and Technology
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• v.33 no.2
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• pp.76-85
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• 2020

A stainless-steel needle (Hamilton 90022, 22 gauge, 718-㎛ o.d., 413-㎛ i.d., 51-mm length, bevel tip) with an electrochemically coated polyaniline layer having a microbore tunnel was newly prepared as a device for headspace in-needle microextraction. For designing the needle, the polyaniline layer length was optimized, and to evaluate the extraction efficiency for polycyclic aromatic hydrocarbons, numerous cyclic voltammetry scans were conducted. In addition, the optimization of the analytical conditions (including the adsorption and desorption parameters) and the validation of the analytical method were conducted. The optimized adsorption and desorption conditions were 40 ℃ for 30 min and 230 ℃ for 60 s, respectively. Finally, in this study, a polyaniline layer was electrochemically deposited on the in-needle surface, and it exhibited good thermal stability. The needle with the polyaniline layer was repeatedly used more than 200 times during this study. This method has some advantages in terms of the extraction time, extraction efficiency, and analysis cost.

• Analytical Science and Technology
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• v.36 no.2
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• pp.89-98
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• 2023

Analytical methods for detecting atranol, chloroatranol, evernic acid, (+)-usnic acid, and atranorin in sanitary napkins and mouthwashes were developed using ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). UHPLC-MS/MS conditions were optimized for rapid, sensitive, and simultaneous analysis of the five allergenic compounds. The methods were validated by assessing their specificity, matrix effects, limit of detection (LOD), limit of quantification (LOQ), linearity, accuracy, and precision. Good linearity was achieved with a determination coefficient of ≥0.99. The LOD and LOQ were 2.1-9.8 and 6.4-29.6 ng/g for sanitary napkins and 0.29-0.48 and 0.87-1.45 ng/mL for mouthwashes, respectively. The accuracy and precision were within an acceptable range according to the criteria reported in the European SANTE/11813/2017 guidelines (70-120 % recovery, <20 % relative standard deviation). Therefore, these methods can be used to analyze atranol, chloroatranol, evernic acid, (+)-usnic acid, and atranorin in sanitary napkins and mouthwashes.

• Analytical Science and Technology
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• v.36 no.6
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• pp.281-290
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• 2023

Zidovudine is an antiretroviral agent prescribed for the prevention and treatment of human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS). It is typically recommended to be used in combination with other antiretroviral drugs. Zidovudine has the potential to generate N-nitrosodimethylamine (NDMA) in the presence of dimethylamine and nitrite salt under acidic reaction conditions during the drug manufacturing process. NDMA is a potent human carcinogen that may be detected in drug substances or drug products. An analytical method was developed to determine NDMA in pharmaceuticals including zidovudine using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The analysis involved reversed-phase chromatography on a Kinetex F5 column with a mobile phase comprising water-acetonitrile mixtures. The detection of positively charged ions was conducted using atmospheric pressure chemical ionization (APCI). The calibration curve demonstrated excellent linearity (r = 0.9997) across the range of 1-50 ng/mL with a highly sensitive limit of detection (LOD) at 0.3 ng/mL. The developed method underwent thorough validation for specificity, linearity, accuracy, precision, robustness, and system suitability. This sensitive and specific analytical method was applied for detecting NDMA in zidovudine drug substance and its formulation currently available in the market, indicating its suitability for drug quality management purposes.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.172-187
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• 2024

In good laboratory practice (GLP), analytical method validation prior to toxicity testing is important in terms of concentration setting and sample preparation. The testing agency performed validation of the two requested test substances using high-performance liquid chromatography (HPLC), and as a result, the analysis satisfied the criteria for specificity, system suitability, linearity, intra-day reproducibility, homogeneity, stability, concentration analysis, and quality control. The method was established and validated. However, the content of standard substances in the test report of the requesting institution was found to be 1.34 and 1.17 times higher than the results of the testing institution, confirming that deriving results through validation of analysis methods suitable for GLP is important in terms of securing reliability and stability.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.2
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• pp.205-214
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• 2004

This paper presents design concepts, specifications and performances of a newly developed Black Box, the reconstruction analysis tool with the records, and results of validation tests. The Black Box can detect crash accidents automatically, and record the vehicle's motion and driver's maneuvers during a pre-defined time period before and after the accident. The items of the Black Box included the acceleration, yaw-rate, vehicle speed, engine RPM, braking application, steering and several digital inputs for recording driver's maneuvers. To detect the accident-related-crash, it is important to understand characteristics of the crash signal, which are much different from those of normal driving. Therefore, analytical considerations should be taken in designing pre-filtering circuits and selecting appropriate parameters for identifying crash accidents. And, it is necessary to select proper combination of motion sensors and design proper pre-filtering circuits in order to describe the vehicle's motion. The analysis algorithms were developed and implemented which can perform accurate detection of crash accidents, simulating pre-crash trajectories, and calculating parameters for reconstruction analysis of crash accidents. The developed Black Box was installed on passenger cars and several types of validation tests were conducted. Through the tests, the accuracy of the recorded data and usefulness of the analysis tool for reconstruction have been validated.

• Food Science of Animal Resources
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• v.43 no.6
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• pp.949-960
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• 2023

This research aimed to validate a high-performance liquid chromatography method for the quantitative determination of bixin and norbixin in various foods. The Diode Array Detector (495 nm) technique was used. Method was validated for specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy, and the measurement uncertainty was assessed. The calibration curve showed excellent linearity (r²≥0.9999) over the tested concentration range of 0.2-25 mg/L. The LOD and LOQ were 0.03-0.11 and 0.02-0.05 mg/L for bixin and norbixin, respectively. The intra-and inter-day accuracies and precisions were 88.0±1.3-97.0±0.5% and 0.2%-2.6% relative SD (RSD) for bixin and 88.2±0.8-105.8±0.8% and 0.3%-2.7% RSD for norbixin, respectively. Inter-laboratory validation for accuracy and precision was conducted in three laboratories, and these results all met the AOAC guidelines. In addition, the relative expanded uncertainty (<22%) satisfied the CODEX recommendation. Furthermore, products distributed in Korea were monitored for annatto extracts using the proposed method to demonstrate its application. The developed analytical method is reliable for quantifying bixin and norbixin in various foods.

• Natural Product Sciences
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• v.10 no.6
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• pp.262-267
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• 2004

A reversed-phase liquid chromatographic method for decursin and decursinol angelate of Angelicae gigantis Radix, an important crude drug in Korean traditional medicine, was developed and validated. Decursin and decursinol angelate, the structure isomer (pyranocoumarin) each other, are the main organic constituents in Angelicae gigantis Radix. This method was developed using a RP-18 column, UV detector at 280 nm and 50% acetonitrile solution containing 0.01 M sodium dodecyl sulfate and 25 mM sodium dihydrogen phosphate (pH 5.0) as the mobile phase. Various validation parameters were included and evaluated satisfactorily. Linearity was established in range 2-75 mg/ml of decursin and decursinol angelate (correlation coefficient = 0.9997 and 0.9995, respectively). This analytical method showed good accuracy (98.1% and 99.5%, respectively). Precision (repeatability) revealed a relative standard deviation value of 1.71% (decursin) and 3.19% (decursinol angelate). For intermediate precision measure the considered variables were equipment and days. A robustness test showing the influence of deferent counter-ion concentration in mobile phase was also performed.

• Nuclear Engineering and Technology
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• v.51 no.2
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• pp.579-587
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• 2019

This paper provides further validation of the burst pressure estimation equations for multiple axial surface cracked steam generator tubes, recently proposed by the authors based on analytical local collapse load approach against systematic FE damage analysis results of Alloy 690 tubes with twin axial surface cracks. Wide ranges of the relative crack depth and multiple crack configurations are considered. Comparison shows good agreements, giving sufficient confidence of the proposed equations.

• Journal of Power Electronics
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• v.19 no.2
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• pp.591-601
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• 2019

With the development of renewable energy, grid-connected inverter technology has become an important research area. When compared with traditional silicon IGBT power devices, the silicon carbide (SiC) MOSFET shows obvious advantages in terms of its high-power density, low power loss and high-efficiency power supply system. It is suggested that this technology is highly suitable for three-phase AC motors, renewable energy vehicles, aerospace and military power supplies, etc. This paper focuses on the SiC MOSFET behaviors that concern the parasitic component influence throughout the whole working process, which is based on a three-phase grid-connected inverter. A high-speed model of power switch devices is built and theoretically analyzed. Then the power loss is determined through experimental validation.