• 분석과학
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• 제36권1호
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• pp.1-11
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• 2023

A new, sensitive, and reliable flow injection methodology was investigated for the determination of lead ion (II) in vegetables' samples using a laboratory-prepared reagent 2-[(6-methoxy-2-benzothiazoly)azo]-4-methoxy phenol (6-MBTAMP). Infrared spectroscopy, UV-visible spectrophotometry, Energy dispersive X-ray spectroscopy (EDX), Elemental Analysis (CHN), nuclear magnetic resonance spectroscopy ¹HNMR, and ¹³CNMR techniques were used to characterize the reagent and lead (II) complex. The method is based on lead ion (II) reacting with the reagent (6-MBTAMP) in a neutral solution to produce a green-red complex with a maximum absorbance at 670 nm. The optimum conditions, such as flow rate, lead ion (II) volume, reagent volume, medium pH, reagent concentration, and reaction coil length were thoroughly examined. The limits of detection (LOD) and quantification (LOQ) were determined to be 0.621 mg·L^-1 and 2.069 mg·L^-1 , respectively, while Sandell's sensitivity was determined to be 0.345 ㎍·cm^-2.

• 한국산업보건학회지
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• 제9권2호
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• pp.167-176
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• 1999

A new analytical procedure for the measurement of monomeric isocyanates and total isocyanate group in workplaces has been investigated. The method described herd involves derivatization of the isocyanate sample upon collection with the reagent 9-anthracenylmethyl 1-piperazinecarboxylate (PAC). Laboratory investigations have demonstrated that excess PAC reagent can be satisfactorily removed from PAC-derivatized monomeric isocyanates-a requirement for the success f the analytical procedure. After removal of excess PAC reagent, the PAC derivatives of butyl isocyanate, phenyl isocyanate, HDI, MDI, and TDI were reacted with sodium thiomethoxide to convert them all to 9-anthracenylmethyl methyl sulfide (AMMS). Total isocyanate group was determined by HPLC analysis and quantification of the single AMMS peak. This circumvents many of the disadvantages associated with current HPLC methods. There were no longer problems associated with quantifying late-eluting peaks and analysis times were very short. A single detector was used for quantification because a standard of the analyte existed and the retention time could be determined. Because all species were converted to a single analyte, the problem of variability of response factors among different species was averted. Finally, there were no complex chromatograms to interpret. Monomers of other individual species were measured by analysis of the sample before the individual species were converted to AMMS. The favorable performance of PAC warrants its further study as a reagent for the determination of total isocyanate group in air.

• 센서학회지
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• 제32권2호
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• pp.67-74
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• 2023

A microfluidic paper-based analytical device (µPAD) is proposed for the selective detection of ammonia in water by using the modified Berthelot reagent and a fluidic channel consisting of hollow paper. The modified Berthelot reagents were uniformly dispersed in cyclohexane and then immobilized in a detection zone of the µPAD. The loading position of the reagents and the type of a sample flow channel were optimized to achieve a sensitive ammonia detection within a short analytical time. The NH₃ µPAD exhibits a linear colorimetric response to the concentration of ammonia dissolved in water in the range of 1-100 mg L^-1, and its limit-of-detection is 1.75 mg L^-1. In addition, the colorimetric response was not influenced by the addition of 100 mg L^-1 nitrogen containing compounds (sodium nitrate, sodium nitrite, uric acid, hydroxylamine, butylamine, diethylamine) or inorganic salts (NaCl, Na₂HPO₄), presenting the enough selectivity in the detection of water-dissolved ammonia against possible interferents.

• 분석과학
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• 제22권2호
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• pp.166-171
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• 2009

잠재지문 현출방법 중 분말법을 이용한 현출법은 현장에서 간편하게 감식하여 개인식별이 가능한 장점으로 선호하는 현출법이다. 따라서 분말형태로의 현출제 개발은 지속적으로 연구되고 있으며 개발분말의 평가법으로는 유류된 지문이나 장문에 비교되는 현출제와 비교하고자 하는 현출제를 1/2씩 현출한 후 대조화면으로 제시하여 저자의 주관적인 방법으로 표현하는 것이 일반적이다. 이에 본 연구에서는 잠재지문 분말현출제의 효율 평가법을 객관화하기 위한 방법을 제시하고자 하였으며 (1) 지문의 동일한 영역에서의 특징점 수 확인 (2) 현출제와 흡착정도(scattering) (3) 현출지문의 contrast 등을 제안하여 현 출효율을 보다 객관적으로 평가할 수 있는 방법임을 확인하였다.

• 대한화학회지
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• 제68권1호
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• pp.20-24
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• 2024

This article presents the advantages of utilizing gossypol and its derivatives as reagents for iron (III) (Fe (III)) ions. A novel spectrophotometric method has been developed for the determination of Fe (III) using gossypol derivatives in the presence of a universal buffer solution. Optimal conditions have been identified, and the composition and stability constants of the Fe (III) complex with gossypolacetic acid have been determined.

• 분석과학
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• 제26권6호
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• pp.357-363
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• 2013

Selenium-containing proteins were separated from selenium-enriched yeast (SEY) using Trizol$^{(R)}$ reagent followed by anion exchange (AE) chromatography. This method is simpler and less time consuming than electrophoresis. Five selenium containing proteins were identified by on-line AE HPLC-ICP/MS (high performance liquid chromatography-inductively coupled plasma/mass spectrometry). Each protein was enzymatically hydrolyzed to seleno-amino acids and separated with RP (reverse phase) HPLC for the identification of selenoproteins.

• 분석과학
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• 제6권4호
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• pp.405-409
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• 1993

Memantine HCl을 자외부 유도화제인 MPCN과 반응시켜 흡광광도법으로 정량하였다. 유도화반응은 pH 5, $50^{\circ}C$에서 MPCN을 1:20배 몰비로 사용하여 30분간 반응시켰으며 dichloromethane으로 추출한 후 324.5nm에서 흡광도를 측정하였다. 그 결과 memantine HCl의 최종 농도로써 $5.0{\times}10^{-6}{\sim}6.5{\times}10^{-5}M$ 사이에서 직선성을 나타냈으며 detection limit는 $0.43{\mu}g/ml$이었다. 본 분석법을 제제에 적용하였을 때 주사제는 $100.08{\pm}0.72%$였고 정제는 $99.75{\pm}0.77%$로, 부형제에 의한 영향 없이 간편하고 신속하게 재현성 있는 결과를 나타내므로 의약품의 품질관리에 효과적으로 응용될 수 있으리라 사료된다.

• 분석과학
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• 제30권2호
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• pp.75-81
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• 2017

5-methylthioninhydrin (5-MTN) is an amino acid sensitive reagent used for the development of latent fingermarks deposited on porous surfaces such as paper and wood. The present study demonstrates that the 5-MTN can be used as a latent footwear impression enhancement reagent, by reacting with trace multivalent metal ions, which are the main components of the latent footwear impression. 5-MTN and L-alanine complex (MTN-ALA) used for the latent footwear impression development was prepared, by mixing $4.5{\times}10^{-3}M$ 5-MTN (in methanol) and $4.5{\times}10^{-3}M$ L-alanine (in methanol) in 1:1 ratio, and keeping undisturbed at room temperature for 24 h. The latent footwear impressions were deposited on white and black non-porous surfaces (glass plate, polyethylene panel, polypropylene panel, acryl panel, polyvinyl chloride (PVC) panel, poly(methyl methacrylate) (PMMA) panel, acrylonitrile-butadiene-styrene (ABS) panel, tile), and a semi-porous surfaces (painted wood). The latent footwear impressions on these surfaces were treated with MTN-ALA complex by spraying. The fluorescence of footwear impressions (occurred due to the reaction between MTN-ALA and metal complexes) was observed under a 505 nm forensic light source and an orange barrier filter. The enhancement of latent footwear impression was achieved from black surfaces without any blurring. However, the fluorescence (enhancement) of footwear impression was not observed on the white PVC, PMMA, and ABS surfaces, because the incident light interfered and reflected on the surface. The sensitivity of MTN-ALA was superior to 2,2'-dipyridil, which is a representative non-fluorescing footwear impression enhancement reagent, and similar to 8-hydroxyquinoline, which is a representative fluorescing footwear impression enhancement reagent.

• Bulletin of the Korean Chemical Society
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• 제27권6호
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• pp.875-880
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• 2006

A new, simple and fast flow injection analysis (FIA) method has been developed for the indirect determination of nitrite. The proposed indirect automatic method is based on the oxidation of nitrite to nitrate using a lead(IV) dioxide oxidant microcolumn where the flow of the sample through the microcolumn reduces the $PbO_2$ solid phase reagent to Pb(II), which is measured by flame atomic absorption spectrometry. The absorbance of Pb(II) are proportional to the concentration of nitrite in the samples. The calibration curve was linear up to 30 mg $L ^{-1}$, with a detection limit of 0.11 mg $L ^{-1}$ for a 400 mL injected sample volume and a sampling rate of about 80 $h ^{-1}$. The results exhibit no interference from the presence of large amounts of ions. The developed procedure was found to be suitable for the determination of nitrite in foodstuffs and wastewaters. A relative standard deviation better than 0.9% was obtained in a repeatability study. The reliability of the method was established by parallel determination against the standard method.

• 분석과학
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• 제7권4호
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• pp.441-453
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• 1994

수질에서 유해물질을 농축하는 방법으로 액체 추출법과 고체상 추출법을 GC/MS를 검출기로 사용하여 비교하였다. 비휘발성 유해물질 중 11종의 산과 44종의 염기/중성 화합물들을 reagent water에 첨가하여 분석한 결과, 액체추출법은 54종의 화합물에 대해 91%의 평균회수율과 4.6%의 평균상대표준편차를 나타내었으며, 고체상 추출법은 52종의 화합물에 대해 63%의 평균회수율과 8.9%의 평균상대표준편차를 보였다. 두 방법의 검출한계는 $1{\sim}5{\mu}g/l$였다.