• Title/Summary/Keyword: Chemometrics

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Template Synthesis of Nitrogen-Doped Short Tubular Carbons with Big Inner Diameter and their Application in Electrochemical Sensing

  • Cheng, Rui;Zou, Qiong;Zhang, Xiaohua;Xiao, Chunhui;Sun, Longfei;Chen, Jinhua
    • Bulletin of the Korean Chemical Society
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    • v.35 no.8
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    • pp.2423-2430
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    • 2014
  • Nitrogen-doped short tubular carbons (N-STCs) with big inner diameter have been successfully synthesized via carbonization of polydopamine (PDA) wrapped halloysite nanotubes (HNTs). The obtained N-STCs have average length of $0.3{\mu}m$ with big inner diameter (50 nm), thin wall (2-3 nm) and large surface area ($776m^2g^{-1}$), and show excellent electrochemical properties. As an example in electrochemical applications, N-STCs were used to electrochemically detect hydrogen peroxide ($H_2O_2$) and glucose. The results showed that the N-STCs modified glassy carbon (N-STCs/GC) electrode had much better analytical performance (lower detection limit and wider linear range) compared to the acid-treated carbon nanotubes (AO-CNTs) based GC electrode. The unique structure endows N-STCs the enhanced electrochemical performance and promising applications in electrochemical sensing.

Simultaneous Electrochemical Determination of Hydroquinone, Catechol and Resorcinol at Nitrogen Doped Porous Carbon Nanopolyhedrons-multiwall Carbon Nanotubes Hybrid Materials Modified Glassy Carbon Electrode

  • Liu, Wei;Wu, Liang;Zhang, Xiaohua;Chen, Jinhua
    • Bulletin of the Korean Chemical Society
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    • v.35 no.1
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    • pp.204-210
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    • 2014
  • The nitrogen doped porous carbon nanopolyhedrons (N-PCNPs)-multi-walled carbon nanotubes (MWCNTs) hybrid materials were prepared for the first time. Combining the excellent catalytic activities, good electrical conductivities and high surface areas of N-PCNPs and MWCNTs, the simultaneous determination of hydroquinone (HQ), catechol (CC) and resorcinol (RE) with good analytical performance was achieved at the N-PCNPs-MWCNTs modified electrode. The linear response ranges for HQ, CC and RE are 0.2-455 ${\mu}M$, 0.7-440 ${\mu}M$ and 3.0-365 ${\mu}M$, respectively, and the detection limits (S/N = 3) are $0.03{\mu}M$, $0.11{\mu}M$ and $0.38{\mu}M$, respectively. These results are much better than that obtained on some graphene or CNTs-based materials modified electrodes. Furthermore, the developed sensor was successfully applied to simultaneously detect HQ, CC and RE in the local river water samples.

Optimization red emission of SrMoO4: Eu3+ via hydro-thermal co-precipitation synthesis using orthogonal experiment

  • Tan, Yongjun;Luo, Xuedan;Mao, Mingfu;Shu, Dehua;Shan, Wenfei;Li, Guizhi;Guo, Dongcai
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1403-1409
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    • 2018
  • In the present study, the $SrMoO_4:Eu^{3+}$ phosphors has been synthesized through hydro-thermal co-precipitation method, and single factor and orthogonal experiment method was adopted to find optimal synthesis condition. It is interesting to note that hydro-thermal temperature is a prominent effect on the luminescent intensity of $SrMoO_4:Eu^{3+}$ red phosphor, followed by co-precipitation temperature, calcining time, and the doping amount of $Eu^{3+}$. The optimal synthesis conditions were obtained: hydro-thermal temperature is $145^{\circ}C$, co-precipitation temperature is $35^{\circ}C$, the calcining time is 2.5 h, and the doping amount of activator $Eu^{3+}$ is 25%. Subsequently, the crystalline particle size, phase composition and morphology of the synthesized phosphors were evaluated by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results show that these phosphors possess a scheelite-type tetragonal structure, and the particle size is about $0.2{\mu}m$. Spectroscopic investigations of the synthesized phosphors are carried out with the help of photo-luminescence excitation and emission analysis. The studies reveal that $SrMoO_4:Eu^{3+}$ phosphor efficiently convert radiation of 394 nm-592 and 616 nm for red light, and the luminescence intensity of $SrMoO_4:Eu^{3+}$ phosphors is improved. $SrMoO_4:Eu^{3+}$ phosphors may be a potential application for enhancing the efficiency of white LEDs.

A Study on the Several Robust Regression Estimators

  • Kim, Jee-Yun;Roh, Kyung-Mi;Hwang, Jin-Soo
    • Journal of the Korean Data and Information Science Society
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    • v.15 no.2
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    • pp.307-316
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    • 2004
  • Principal Component Regression(PCR) and Partial Least Squares Regression(PLSR) are the two most popular regression techniques in chemometrics. In the field of chemometrics usually the number of regressor variables greatly exceeds the number of observation. So we have to reduce the number of regressors to avoid the identifiability problem. In this paper we compare PCR and PLSR techniques combined with various robust regression methods including regression depth estimation. We compare the efficiency, goodness-of-fit and robustness of each estimators under several contamination schemes.

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Evaluation of Larynx Cancer via Chemometrics Assisted Raman Spectroscopy

  • Senol, Onur;Albayrak, Mevlut
    • Current Optics and Photonics
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    • v.3 no.2
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    • pp.150-153
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    • 2019
  • Larynx cancer is a potentially terminal and severe type of neck and head cancer in which malignant cells start to grow and spread upwards in the larynx, or voice box. Smoking tobacco, drinking hot beverages and drinking alcohol are the main risk factors for these tumors. In this study, we aimed to develop a precise, accurate and rapid chemometrics assisted Raman spectroscopy method for diagnosis of larynx cancer in deparaffinized tissue samples. In the proposed method, samples were deparaffinized and 20 microns of each tissue were located on a coverslip. Both healthy (n = 13) and cancerous tissues (n = 13) were exposed to a Raman laser (785 nm) and excitations were recorded between wavenumbers of $50{\sim}1500cm^{-1}$. An Orthogonal Partial Least Square algorithm was applied to evaluate the Raman spectrum obtained. Sensitivity and specificity of the proposed method is high enough with the aid of Principal Component Analysis (PCA) to test the whole model. Healthy and cancerous tissues were accurately and precisely clustered. A rapid, easy and precise diagnosis algorithm was developed for larynx cancer. By this method, some useful data about differences in biomolecules of each group (phospholipids, amides, tyrosine, phenylalanine collagen etc.) was also obtained from the spectra. It is claimed that the optimized method has a great potential for clustering and separating tumor tissues from healthy ones. This novel, rapid, precise and objective diagnosis method may be an alternative for the conventional methods in literature for diagnosis of larynx cancer.

Elemental Analysis in Astragali Radix by Using ICP-AES and Determination of the Original Agricultural Place of Oriental Medicine by Using a Chemometrics (ICP-AES를 이용한 황기 속에 함유된 원소의 성분 분석과 Chemometrics를 이용한 한약재의 원산지 규명)

  • Kang, Mi Ra;Lee, Ick Hee;Jun, Hyuong;Kim, Yongseong;Lee, Sang Chun
    • Analytical Science and Technology
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    • v.14 no.4
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    • pp.311-316
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    • 2001
  • We have investigated the trace amount in an oriental medicine in oder to determine the geographical origin by using inductively coupled plasma-atomic emission spectrometry(ICP-AES) and chemometric anlysis with principal component analysis(PCA) and pattern recognition. Astragali Radix from several agricultural places in Korea was selected as an example of the oriental medicine and analyzed by ICP-AES. The dried Astragali Radix sample was treated with $HNO_3$ and $H_2O_2$, then digested using microwave oven. Elements such as Mg, Al, K, Ca, Ti, Mn, Fe, Cu, Zn, and Ba with different concentrations were found an used for the identification of the origin of agriculture places. Especially, the concentration of Al, Fe, Zn and Ti were employed to investigate the relationship between. Astragali Radix and the agricultural places by PCA and pattern recognition. We have made a program that is based on chemometrics in analytical spectroscopy. The results of the chemometrics analysis indicated that a distinction among Yechon and Chechon, Chungson, Kurye and Chinese Astragali Radix could be made. We believe that principal component analysis(PCA) and pattern recognition is a valuable tool to identify the origin of Astragali Radix in terms of the agricultural place.

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A Review of the Applications of Spectroscopy for the Detection of Microbial Contaminations and Defects in Agro Foods

  • Kandpal, Lalit Mohan;Cho, Byoung-Kwan
    • Journal of Biosystems Engineering
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    • v.39 no.3
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    • pp.215-226
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    • 2014
  • Recently, spectroscopy has emerged as a potential tool for quality evaluation of numerous food and agricultural products because it provides information regarding both spectral distribution and image features of the sample (i.e., hyperspectral imaging). Spectroscopic techniques reveal hidden information regarding the sample and do so in a non-destructive manner. This review describes the various approaches of spectroscopic modalities, especially hyperspectroscopy and vibrational spectroscopies (i.e., Raman spectroscopy and Fourier transform near infrared spectroscopy) combined with chemometrics for the non-destructive assessment of contaminations and defects in agro-food products.

Trends in non- destructive analysis using near infrared spectroscopy in food industry (식품 산업에서의 근적외선 분광법을 이용한 비파괴 분석법 동향)

  • Park, Jong-Rak
    • Food Science and Industry
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    • v.55 no.1
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    • pp.2-22
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    • 2022
  • Near-infrared spectroscopy (NIRS) is one of the representative non-destructive and eco-friendly analysis methods used for rapid analysis of various ingredients in the food industry. To develop analysis model with NIRS, Chemometrics are applied after pre-treatment of spectrum. Many studies have been reviewed on the analysis of general and functional components for agricultural and livestock products. In the case of livestock products, some studies have been conducted for on-line analysis. This study investigated results on various samples and component applying near-infrared spectroscopy. Furthermore, the results according to sample condition were compared. It was confirmed that NIRS is applied to various fields in the food industry.

Development of On-line Quantitative Analysis for Bioethanol Using Infrared Spectroscopy (적외선 분광분석을 이용한 바이오 에탄올 on-line용 정량분석법 개발)

  • Kim, Hyeonguk;Ryu, Jun-Hyung;Liu, J. Jay
    • Applied Chemistry for Engineering
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    • v.23 no.1
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    • pp.35-41
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    • 2012
  • This paper proposes a new methodology for the real-time on-line quality monitoring of biofuel processes through the integration of infrared spectroscopy and chemometrics. A method of Partial Least Squares (PLS) in Chemometrics is employed for quantitative analysis of key components in bioethanol products. After a number of preprocessing methods and variable importance in projection (VIP) are used, Savitzky-Golay method showed the best performance in terms of spectrum correction, noise reduction, and model maintenance. The proposed method allows us to economically forecast the concentration of multiple impurities encountered with the production of bioethanol. The proposed system is also accurate enough ($R^2$ > 0.99) to replace the laboratory analysis.