Peter Harrington | Ohio University (original) (raw)

Papers by Peter Harrington

Journal of AOAC INTERNATIONAL, 2011

This study describes the use of spectral fingerprints acquired by flow injection (FI)-MS and mult... more This study describes the use of spectral fingerprints acquired by flow injection (FI)-MS and multivariate analysis to differentiate three Panax species: P. ginseng, P. quinquefolius, and P. notoginseng. Data were acquired using both high resolution and unit resolution MS, and were processed using principal component analysis (PCA), soft independent modeling of class analogy (SIMCA), partial least squares-discriminant analysis (PLS-DA), and a fuzzy rule-building expert system (FuRES). Both high and unit resolution MS allowed discrimination among the three Panax species. PLS-DA and FuRES provided classification with 100% accuracy while SIMCA provided classification accuracies of 77 and 88% by high- and low-resolution MS, respectively. The method does not quantify any of the sample components. With FI-MS, the analysis time was less than 2 min.

2008 Fourth International Conference on Natural Computation, 2008

ABSTRACT Support victor machine (SVM) and artificial neural networks (ANNs) including back-propag... more ABSTRACT Support victor machine (SVM) and artificial neural networks (ANNs) including back-propagation network (BPNN) and radial basis function network (RBFNN) were used to investigate toxic effect of phenols on fathead minnows. Molecular connectivity index was used as structural descriptor. The applicability of established BPNNs, RBFNNs and SVM models based on optimized parameters was compared using leave-one-out (LOO) cross-validation method. Results showed that all the models investigated were applicable for the quantitative structure-activity relationship (QSAR) studies and the SVM model is slightly better than others. The correlation coefficients between measured toxicities and predicted values of SVM, BPNN and RBFNN models are 0.959, 0.94, and 0.945, respectively.

2012 9th International Conference on Fuzzy Systems and Knowledge Discovery, 2012

ABSTRACT The feasibility of early diagnosis of endometrial carcinoma was studied by high dimensio... more ABSTRACT The feasibility of early diagnosis of endometrial carcinoma was studied by high dimensional data analysis (HDDA) that classified near infrared (NIR) spectra of tissues. NIR spectra of 77 specimens of endometrium were collected. The spectra were pretreated by principal component orthogonal signal correction (PC-OSC) and emphatic orthogonal signal correction (EOSC) methods to improve the signal-to-noise ratio (SNR) and remove the influences of background and baseline. The effects of modeling parameters were investigated using bootstrapped Latin-partition methods. The optimal HDDA model of the PC-OSC pretreatment method successfully classified the samples with prediction accuracies of 95.2 ± 1.9%. The proposed procedure proved to be rapid and convenient, which is suitable to be developed as a non-invasive diagnosis method for cancer tissue.

Talanta, 2015

Gold nanoparticles (AuNPs) and reduced graphene oxide (graphene) composites were synthesized via ... more Gold nanoparticles (AuNPs) and reduced graphene oxide (graphene) composites were synthesized via a simple one-pot approach in the presence of polyvinylpyrrolidone (PVP). Further, the Au-PVP-graphene nanocomposite was used as a new sensing material for the electrochemical detection of butylated hydroxyanisole (BHA). Because of the greatly enlarged surface area, the enhanced electron transfer rate, and a stronger enrichment of BHA, the sensor based on Au-PVP-graphene modified glassy carbon electrode (GCE) displayed highly sensitive electrochemical responses to BHA. Applying linear sweep voltammetry, a good linear relationship of the oxidation peak current with respect to concentrations of BHA across the range of 0.2 ~ 100.0 µM and a detection limit of 0.04 µM were achieved. The practical analytical performance of the Au-PVP-graphene/GCE was examined by evaluating detection of BHA in soybean oil and the flour samples. Satisfactory results revealed that this work offered a new way for the sensitive and simple determination of BHA in complex samples. Highlights • The Au-PVP-graphene (GR) nanocomposite was synthesized via a simple approach. • The enlarged surface area and the enhanced electron rate of composite were discussed. • A sensitive electrochemical sensor of butylated hydroxyanisole (BHA) was built. • The electrochemical reaction mechanism of BHA was proposed. • The saturating absorption capacity at Au-PVP-graphene/GCE was calculated.

Talanta, 1998

A tubular silicone membrane interface has been developed for trace detection of benzene, toluene,... more A tubular silicone membrane interface has been developed for trace detection of benzene, toluene, ethyl benzene, and xylene (BTEX) compounds in water with a portable ion mobility spectrometer. Effects of flow rate, membrane length and stirring conditions on the IMS signals have been systematically investigated. Besides conventional dynamic mode operation, static mode sampling has been demonstrated for the first time and high sensitivities were achieved by sampling of BTEX contaminated water with static mode operation. A toluene concentration of 0.101 mg l − 1 in purified water, corresponding to a headspace concentration of 2.75 (mg m − 3), was determined by static mode sampling. Headspace sampling without the membrane interface could not detect toluene at this concentration. This method has high sensitivity for trace concentrations of gasoline components in river water with a response time of several seconds. The apparatus developed is portable and can be used for sensitive detection of organic contaminants in water, with improved performance compared to conventional modes of IMS sampling.

Luminescence, 2013

Acetaminophen, also called paracetamol, is found in Tylenol, Excedrin and other products as over-... more Acetaminophen, also called paracetamol, is found in Tylenol, Excedrin and other products as over-the-counter medicines. In this study, acetaminophen as a luminol signal enhancer was used in the chemiluminescence (CL) substrate solution of horseradish peroxidase (HRP) for the first time. The use of acetaminophen in the luminol-HRP-H 2 O 2 system affected not only the intensity of the obtained signal, but also its kinetics. It was shown that acetaminophen was to be a potent enhancer of the luminol-HRP-H 2 O 2 system. A putative enhancement mechanism for the luminol-H 2 O 2-HRP-acetaminophen system is presented. The resonance of the nucleophilic amide group and the benzene ring of acetaminophen structure have a great effect on O-H bond dissociation energy of the phenol group and therefore on phenoxyl radical stabilization. These radicals act as mediators between HRP and luminol in an electron transfer reaction that generates luminol radicals and subsequently light emission, in which the intensity of CL is enhanced in the presence of acetaminophen. In addition, a simple method was developed to detect acetaminophen by static injection CL based on the enhanced CL system of luminol-H 2 O 2-HRP by acetaminophen. Experimental conditions, such as pH and concentrations of substrates, have been examined and optimized. The proposed method exhibited good performance, the linear range was from 0.30 to 7.5 mM, the relative standard deviation was 1.86% (n = 10), limit of detection was 0.16 mM and recovery was 99 AE 4%. Copyright

The Journal of Supercritical Fluids, 2004

Complex formation reactions of praseodymium nitrate hexahydrate, and neodymium nitrate hexahydrat... more Complex formation reactions of praseodymium nitrate hexahydrate, and neodymium nitrate hexahydrate salts with tri-n-butyl phosphate (TBP) and several other neutral organophosphorus reagents were investigated in supercritical carbon dioxide. The concentration of the metal complexes in the supercritical fluid (SCF) phase was determined using UV-Vis and luminescence spectroscopies. The stoichiometry of the complexes was determined using the mole-ratio method. Extraction equilibrium constants were calculated from the spectral data using least-squares regression and hard-equilibria models. UV-Vis absorbance data indicate that praseodymium nitrate and neodymium nitrate both form 1:4 lanthanide-tributyl phosphate complexes in supercritical carbon dioxide at 308 K. The conditional extraction coefficients for those two systems were calculated to be log K ex = 7.45 ± 0.06 for the praseodymium system and log K ex = 7.52 ± 0.03 for the neodymium system. For comparison, neodymium nitrate complexation reactions with tri-n-butyl phosphate and tributyl phosphite (TBPO 3) were studied in hexane under ambient conditions. UV-Vis data indicate that a 1:4 neodymium-tributyl phosphate complex is formed in hexane with a conditional extraction coefficient of log K ex = 3.4±0.2. Tributyl phosphite forms a 1:8 complex with neodymium in hexane with a conditional extraction coefficient of log K ex = 11.0 ± 0.1. Neodymium nitrate was titrated with other organophosphorus reagents, tributyl phosphite and tributyl phosphine oxide (TBPO), in supercritical carbon dioxide to investigate differences between neutral oxygen donor ligands and neutral phosphorus donor ligands. UV-Vis and luminescence data indicate that neodymium nitrate forms a 1:8 complex with tributyl phosphite and a 1:5 complex with tributyl phosphine oxide, compared to a 1:4 complex with tri-n-butyl phosphate. The conditional extraction coefficient for the 1:8 neodymium-tributyl phosphite system was calculated as log K ex = 21.4±0.2 from UV-Vis data, and log K ex = 19.8±0.2 from luminescence data. The conditional extraction coefficient for the 1:5 neodymium-tributyl phosphine oxide complex was calculated as log K ex = 7.83±0.05.

Food Chemistry, 2014

In the present study, poly(sodium 4-styrenesulfonate) (PSS) functionalized graphene (GR) was synt... more In the present study, poly(sodium 4-styrenesulfonate) (PSS) functionalized graphene (GR) was synthesized via a simple one-step chemical reduction of exfoliated graphite oxides in the presence of PSS. Characterization of as-made nanocomposite using Fourier transform infrared spectroscopy (FT-IR) and ultraviolet and visible spectroscopy (UV-vis) clearly demonstrate the successful attachment of PSS to graphene sheets. A novel clenbuterol (CLB) electrochemical sensor was fabricated based on isopropanol-Nafion-PSS-GR composite film modified glassy carbon electrode. In the Britton-Robinson buffer (pH 1.2), the sensor exhibited superior electrocatalytic activity towards the oxidation of CLB. Applying linear sweep voltammetry, a good linear relationship of the oxidation peak current with respect to concentrations of CLB cross the range of 7.5×10 −8-2.5×10 −5 mol L −1 and a detection limit of 2.2×10-8 mol L −1 were achieved. The proposed method was successfully applied for the determination of CLB in pork.

Electrochimica Acta, 2014

Poly(sodium 4-styrenesulfonate) (PSS) intercalated graphene (PSS-GN) was prepared via in situ red... more Poly(sodium 4-styrenesulfonate) (PSS) intercalated graphene (PSS-GN) was prepared via in situ reduction of exfoliated graphite oxides in the presence of PSS, and then mixed with CTAB to form a stable PSS-GN-CTAB nanocomposite through electrostatic self-assembly. The prepared composites were characterized by Fourier transform infrared spectrometry (FT-IR), ultraviolet and visible spectrometry (UV-vis) and Xray diffraction (XRD). A novel 2,4-dichlorophenol (2,4-DCP) electrochemical sensor was fabricated based on a PSS-GN-CTAB modified glassy carbon electrode. It was found that the composite of PSS-GN-CTAB exhibited excellent electrocatalytic activity towards the oxidation of 2,4-DCP. Linear sweep voltammetry (LSV) was used for the quantitative determination of 2,4-DCP. Under the optimum conditions, the peak current of 2,4-DCP was proportional to its concentration at the range of 1.0 × 10 −8 to 2.0 × 10 −6 mol L −1 with a detection limit 2.0 × 10 −9 mol L −1. The newly developed method was successfully applied for the determination of 2,4-DCP in the waste water with good recoveries. The proposed electrode system represents a new platform for designing excellent electrochemical sensors with water-dispersed graphene.

Int J Ion Mobil Spectrom, 2004

Received for review January 1, 2004, Accepted June 20, 2004 ALS TO MODELING OF ION MOBILITY SPECT... more Received for review January 1, 2004, Accepted June 20, 2004 ALS TO MODELING OF ION MOBILITY SPECTRA Libo Cao and Peter de B. Harrington ... Figure 1 gives a positive mode collection with a Smiths Detection Chemical Agent Monitor (CAM) from a methanol cap sniff. ...

ED293726 - Using Microcomputer Spreadsheet Programs To Teach Statistical Concepts.

Applied Spectroscopy, 1998

A discrete sine transform (DST) method has been devised for the Fourier compression of ion mobili... more A discrete sine transform (DST) method has been devised for the Fourier compression of ion mobility spectra. The DST allows the calculation of eigenvalues with correct scale directly from the compressed data. A novel procedure for transforming the variable loadings from Fourier to native domains has been devised. For the first time, data may be interpreted in their native domain without decompression of the entire data set. This achievement is significant because results generated from the analysis of compressed data had been restricted to an abstract mathematical form. Methodology to convert these abstract results to a form that is understandable by analytical chemists is presented. This capability has important applications to the analysis of large data sets and embedded data processing under the constraints of miniaturized instrumentation. Five sets of evaluation data were obtained from vapor samples of formamide, 1-pentanol, and a mixture of two chemical warfare simulants (DIMP ...

Analytical Chemistry, 1993

Page 1. Anal. Chem. 1993, 65, 2167-2168 2167 Sigmoid Transfer Functions in Backpropagation Neural... more Page 1. Anal. Chem. 1993, 65, 2167-2168 2167 Sigmoid Transfer Functions in Backpropagation Neural Networks Peter de B. Harrington Center for Intelligent Chemical Instrumentation, Department of Chemistry, Clippinger Laboratories ...

Analytical Chemistry, 1994

Page 1. Anal. Chem. 1994,66, 2047-2051 Optimal Associative Memory for Background Correction of Sp... more Page 1. Anal. Chem. 1994,66, 2047-2051 Optimal Associative Memory for Background Correction of Spectra Bus010 Wa Wabuyele and Peter de B. Harrlngton' Clippinger Laboratories, Center for Intelligent Chemical Instrumentation ...

Analytical Chemistry, 2009

An approach for automating the determination of the number of components in orthogonal signal cor... more An approach for automating the determination of the number of components in orthogonal signal correction (OSC) has been devised. In addition, a novel principal component OSC (PC-OSC) is reported that builds softer models for removing background from signals and is much faster than the partial least-squares (PLS) based OSC algorithm. These signal correction methods were evaluated by classifying fused near-and mid-infrared spectra of French olive oils by geographic origin. Two classification methods, partial least-squares-discriminant analysis (PLS-DA) and a fuzzy rule-building expert system (FuRES), were used to evaluate the signal correction of the fused vibrational spectra from the olive oils. The number of components was determined by using bootstrap Latin partitions (BLPs) in the signal correction routine and maximizing the average projected difference resolution (PDR). The same approach was used to select the number of latent variables in the PLS-DA evaluation and perfect classification was obtained. Biased PLS-DA models were also evaluated that optimized the number of latent variables to yield the minimum prediction error. Fuzzy or soft classification systems benefit from background removal. The FuRES prediction results did not differ significantly from the results that were obtained using either the unbiased or biased PLS-DA methods, but was an order of magnitude faster in the evaluations when a sufficient number of PC-OSC components were selected. The importance of bootstrapping was demonstrated for the automated OSC and PC-OSC methods. In addition, the PLS-DA algorithms were also automated using BLPs and proved effective.

Analytical Chemistry, 2001

The multivariate curve resolution method SIMPLe to use Interactive Self-Modeling Mixture Analysis... more The multivariate curve resolution method SIMPLe to use Interactive Self-Modeling Mixture Analysis (SIMPLISMA) was applied to Fourier and wavelet compressed ionmobility spectra. The spectra obtained from the SIM-PLISMA model were transformed back to their original representation, that is, uncompressed format. SIMPLIS-MA was able to model the same pure variables for the partial wavelet transform, although for the Fourier and complete wavelet transforms, satisfactory pure variables and models were not obtained. Data were acquired from two samples and two different ion mobility spectrometry (IMS) sensors. The first sample was thermally desorbed sodium γ-hydroxybutyrate (GHB), and the second sample was a liquid mixture of dicyclohexylamine (DCHA) and diethylmethylphosphonate (DEMP). The spectra were compressed to 6.3% of their original size. SIMPLISMA was applied to the compressed data in the Fourier and wavelet domains. An alternative method of normalizing SIMPLISMA spectra was devised that removes variation in scale between SIMPLISMA results obtained from uncompressed and compressed data. SIMPLISMA was able to accurately extract the spectral features and concentration profiles directly from daublet compressed IMS data at a compression ratio of 93.7% with root-meansquare errors of reconstruction <3%. The daublet wavelet filters were selected, because they worked well when compared to coiflet and symmlet. The effects of the daublet filter width and compression ratio were evaluated with respect to reconstruction errors of the data sets and SIMPLISMA spectra. For these experiments, the daublet 14 filter performed well for the two data sets.

Analytical and Bioanalytical Chemistry, 2013

A bootstrapped fuzzy rule-building expert system (FuRES) and a bootstrapped t-statistical weight ... more A bootstrapped fuzzy rule-building expert system (FuRES) and a bootstrapped t-statistical weight feature selection method were individually used to select informative features from gas chromatography/mass spectrometry (GC/MS) chemical profiles of basil plants cultivated by organic and conventional farming practices. Feature subsets were selected from two-way GC/MS data objects, total ion chromatograms, and total mass spectra, separately. Four economic classifiers based on the bootstrapped FuRES approach, i.e., fuzzy optimal associative memory (e-FOAM), e-FuRES, partial least-squares-discriminant analysis (e-PLS-DA), and soft independent modeling by class analogy (e-SIMCA), and four economic classifiers based on the bootstrapped t-weight approach, i.e., e-PLS-DA-t, e-FOAM-t, e-FuRES-t, and e-SIMCA-t, were constructed thereafter to be compared with full-size classifiers obtained from the entire GC/MS data objects (i.e., FOAM, FuRES, PLS-DA, and SIMCA). By using three features selected from two-way data objects, the average classification rates with e-FOAM, e-FuRES, e-PLS-DA, and e-SIMCA were 95.3 ± 0.5%, 100%, 100%, and 91.8 ± 0.2%, respectively. The established economic classifiers were used to classify a new validation set collected 2.5 months later with no parametric change to experimental procedure. Classification rates with e-FOAM, e-FuRES, e-PLS-DA, and e-SIMCA were 96.7%, 100%, 100%, and 96.7%, respectively. Characteristic components in basil extracts corresponding to highest-ranked useful features were putatively identified. The feature subset may prove valuable as a rapid approach for organic basil authentication.

Analytica Chimica Acta, 2003

ABSTRACT

Analytica Chimica Acta, 1987

A quantitative measure of library search reliability has been developed. Applications of the quan... more A quantitative measure of library search reliability has been developed. Applications of the quantitative reliability metric (QRM) for evaluating the reliability of library searches for unknown target spectra and the use of this measure to detect the failure of a library search caused by noise, contaminant peaks and missing library spectra are discussed. The effects of noise and composite infrared spectra of mixtures on the QRM are examined for test sets of 561 infrared spectra. The QRM is also used to evaluate the performance of a search of an infrared library compressed by eigenvector projection.

Analytical Chemistry, 1990

Page 1. Anal. Chem. 1990, 62, 729-734 Multivariate Rule Building Expert System 729 Peter de B. Ha... more Page 1. Anal. Chem. 1990, 62, 729-734 Multivariate Rule Building Expert System 729 Peter de B. Harrington*pl and Kent J. Voorhees Department of Chemistry &amp; Geochemistry, Colorado School of Mines, Golden, Colorado 80401 ...