Young-Ah Woo

Discrimination of herbal medicines according to geographical origin with near infrared reflectance spectroscopy and pattern recognition techniques.

Herbal medicines have an important role in clinical therapy in Asian countries such as Korea, Japan, and China. The objective of this study is to develop a nondestructive and accurate analytical method to discriminate herbal medicines according to geographical origin. Even though they are the same species, their qualities are different by growing conditions such as climate and soil. Near infrared (NIR) reflectance spectroscopy and a pattern recognition technique were applied for discrimination of herbal medicines according to geographical origin (Korea and China). Astragali Radix (AR), Ganoderma, and Smilacis Rhizoma (SR) were examined. It is shown that the representative NIR reflectance spectra in each group are different according to geographical origin after second derivatization to enhance spectral features. Also, the NIR reflectance spectra of Chinese and Korean samples were differentiated using principal component (PC) score plots. To establish the discrimination rule, Mahalanobis distance and discriminant analysis with PLS2 were utilized.

Evaluation of open-air type electrolyte-as-cathode glow discharge-atomic emission spectrometry for determination of trace heavy metals in liquid samples

Abstract Electrolyte-as-cathode glow discharge-atomic emission spectrometry (ELCAD-AES) has been used for on-line determination of trace heavy metals in tap and drinking waters and fresh milk. The fundamental characteristics are: pH of electrolytes; discharge current; discharge gap shown influenced the plasma stability; and the intensity of emission lines emitted from different elements of solution. A stable discharge plasma which significantly improved the sensitivity was achieved when approximately 1.6 kV, several tens of milli-amperes current and a few millimeters discharge gap between the Pt rod anode and acidified electrolyte cathode in atmospheric air pressure were applied. Although the OH band dominates the solution spectra between wavelengths of 300 and 700 nm, nine elements including Pb and Cu have been determined from freshly collected unspiked tap and drinking waters and fresh milk. The limits of detection (LOD) of Hg, Pb, Cd, Cu, Na and K were obtained as 0.001–0.08 mg/l. The open-air ELCAD has used for the first time for Hg, Cd, Na and K detection and an improved LOD of Pb was found compared to reported values. The LOD values of Hg, Pb, Cd and Cu improved by more than one order of magnitude compared to closed-type ECLAD.

Classification of cultivation area of ginseng radix with NIR and Raman spectroscopy

A rapid and non-destructive method for the classification of ginseng radix according to cultivation area (Korea and China) was evaluated using near infrared (NIR) reflectance spectroscopy. Ginseng samples were collected from widely different growing areas of Korea and China to give more geographical variations. Although there were no obvious differences in the raw NIR spectra based on cultivation area, the spectral features were enhanced and differentiated by utilizing a second-derivative algorithm. Using principal component analysis the cultivation area was clearly differentiated in the principal component space. To develop a classification rule, partial least squares discriminant analysis was carried out. The origin of ginseng was successfully classified and predicted using NIR reflectance spectroscopy combined with discriminant analysis. Additionally, FT-Raman spectroscopy, which provides more qualitative information and easy sample measurement, was also investigated for the same purpose. The results showed that the classification performance using NIR reflectance spectroscopy was superior to that using Raman spectroscopy.

Determination of hydrogen peroxide concentration in antiseptic solutions using portable near-infrared system.

Hydrogen peroxide (H2O2) concentrations in antiseptic solutions (normally 3% H2O2) has been determined non-destructively using a portable near-infrared (NIR) analyzer. The spectral variation due to -OH band around 1400 nm in the second derivative spectra has been found as H2O2 concentration changes. Both multiple linear regression (MLR) and partial least squares (PLS) were employed to generate calibration models over the 1100-1720 nm range. The PLS calibration model showed the better calibration performance with a standard error of prediction (SEP) of 0.16%. In order to validate the developed PLS calibration model, H2O2 concentrations in commercial antiseptic solutions were predicted and compared with values from a conventional redox titration method. The results showed that NIR predictions had good correlation with conventional analysis values. The rapid and non-destructive determination of H2O2 in the antiseptic solution was successfully performed using portable NIR analyzer without any hazardous chemical solvents.

Classification of cultivation area of ginseng by near infrared spectroscopy and ICP-AES

A rapid and nondestructive near infrared (NIR) method using soft independent modeling of class analogy (SIMCA) for the classification of cultivation area (Korea and China) was evaluated and confirmed. Raw, first, and second derivative NIR spectra were compared to develop a robust classification rule. The chemical properties of ginseng samples were also investigated to find out the differences between Korean samples and Chinese samples. These differences make NIR spectroscopic method viable. The average value of each Korean and Chinese ginseng sample for crude fiber, crude protein, starch, and 10 inorganic constituents were measured and compared with F-test and t-test. The inorganic constituents were also measured by induced coupled plasma-atomic emission spectroscopy (ICP-AES). It could be found that the amount of starch and ten inorganic elements for example Na, Mg, P, K, Ca, Mn, Fe, Ni, Cu and Zn in ginseng samples are considerably different based on cultivation area. SIMCA has been applied to the inorganic data to investigate the possibility of ICP-AES as classification tool. However, it was observed that the result was not equal to than NIR spectra data. The overall results showed the availability of NIR method using SIMCA would be adequate for classification of cultivation of ginseng, since NIR spectra includes useful and various information on chemical properties in spite of broad and overlapped bands.

Determination of water content in skin by using a FT near infrared spectrometer.

The water content of skin was determined using a FT near infrared (NIR) spectrometer. NIR diffuse reflectance spectra were collected from hairless mouse,in vitro, and from human inner arm,in vivo. It was found that the variation of NIR absorbance band 1450 nm from OH vibration of water and 1940 nm from the combination involving OH stretching and OH deformation, depending on the absolute water content of separated hairless mouse skin,in vitro, using the FT NIR spectrometer. Partial least squares regression (PLSR) was applied to develop a calibration model. The PLS model showed good correlation. For practical use of the evaluation of human skin moisture, the PLS model for human skin moisture was developedin vivo on the basis of the relative water content of stratum corneum from the conventional capacitance method. The PLS model predicted human skin moisture with a standard errors of prediction (SEP) of 3.98 at 1130-1830 nm range. These studies showed the possibility of a rapid and nondestructive skin moisture measurement using FT NIR spectrometer.

Rapid qualitative and quantitative evaluation of deer antler (Cervus elaphus) using near-infrared reflectance spectroscopy

Abstract Near-infrared (NIR) spectroscopy has been applied for both the qualitative and quantitative evaluation of the velvet deer antler. The most important parameters of determining the quality of velvet antler are the habitat (the country of origin) and ash content. Conventionally, the habitat is determined by examining the appearance of samples (by human eye), which lacks objectivity. Ash content is measured by an ignition method (measurement ash residue), however, it is too slow (4–5 h) to be used for rapid at-site measurement. Velvet antlers from three different habitats (China, New Zealand, and Russia), albeit the same species of Cervus elaphus, were evaluated in this paper. Soft independence modeling of class analogies (SIMCA) and partial least squares (PLS) were used for classification of habitat and determination of ash content. The habitat was successfully identified with over 80% accuracy, and the ash content prediction result using PLS regression showed good correlation with the reference ignition method with a standard error of prediction (SEP) of 1.264%.

Quantification of CKD-501, lobeglitazone, in rat plasma using a liquid-chromatography/tandem mass spectrometry method and its applications to pharmacokinetic studies.

CKD-501 (i.e., lobeglitazone), a potent agonist for both PPARalpha/gamma, is a new drug that has potential clinical applications in the management of type-2 diabetes. The objective of this study was to develop a rapid and sensitive method for the determination of CKD-501 in rat plasma and to assess the applicability of the assay to pharmacokinetic studies. Rat plasma samples were processed using a fast flow protein precipitation (FF-PPT) method and then introduced onto an LC-MS/MS system for quantification. The analyte and rosiglitazone, an internal standard, were analyzed by multiple reactions monitoring (MRM) at m/z transitions of 482.0-->258.0 for CKD-501 and 358.0-->135.0 for the internal standard. The lower limit of quantification (LLOQ) was determined at 50 ng/mL, with an acceptable linearity in the range from 50 to 10,000 ng/mL (R>0.999). Validation parameters such as accuracy, precision, dilution, recovery, matrix effect and stability were found to be within the acceptance criteria of the assay validation guidelines, indicating that the assay is applicable to estimating the concentration in the range studied. The concentration of CKD-501 was readily quantifiable in plasma samples up to 24 h post-dose in rats that had received an oral dose of 1 mg/kg. These observations suggest, therefore, that the validated assay can be used in pharmacokinetic studies of CKD-501 in small animals such as the rat.

Simple transmission Raman measurements using a single multivariate model for analysis of pharmaceutical samples contained in capsules of different colors.

Direct transmission Raman measurements for analysis of pharmaceuticals in capsules are advantageous since they can be used to determine active pharmaceutical ingredient (API) concentrations in a non-destructive manner and with much less fluorescence background interference from the capsules themselves compared to conventional back-scattering measurements. If a single calibration model such as developed from spectra simply collected in glass vials could be used to determine API concentrations of samples contained in capsules of different colors rather than constructing individual models for each capsule color, the utility of transmission measurements would be further enhanced. To evaluate the feasibility, transmission Raman spectra of binary mixtures of ambroxol and lactose were collected in a glass vial and a partial least squares (PLS) model for the determination of ambroxol concentration was developed. Then, the model was directly applied to determine ambroxol concentrations of samples contained in capsules of 4 different colors (blue, green, white and yellow). Although the prediction performance was slightly degraded when the samples were placed in blue or green capsules, due to the presence of weak fluorescence, accurate determination of ambroxol was generally achieved in all cases. The prediction accuracy was also investigated when the thickness of the capsule was varied.

Near-infrared spectroscopy as a convenient analytical method for alkyl polyglycosides

Near infrared (NIR) spectroscopy is used for the rapid determination of decyl glucopyranoside (10G1) and alkyl polyglycoside (AG) mixtures having different alkyl chain length and the number of glucose unit in aqueous solution. NIR spectroscopy is a much simpler spectroscopic analysis method compared to three analytical methods for mixture of AGs such as thin layer chromatography (TLC), high performance liquid chromatography (HPLC), and photometry method. NIR spectra of AGs between 0.030 and 0.540 mg/ml in aqueous solutions were utilized to develop a calibration model. Both raw spectra and the second derivatives of AGs were tested for the best fit. The best calibration was built with second derivative spectra by using multiple linear regression (MLR). The standard error of calibration (SEC) and the standard error of prediction (SEP) were used for the evaluation of the model. The best calibration provides an SEP of 0.052 and 0.061 mg/ml for the prediction set of 10G1 and AG mixture, respectively.