Journal of Analytical Methods in Chemistry The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Geographical and Seasonal Patterns of Geosmin and 2-Methylisoborneol in Environmental Water in Jiangsu Province of China Thu, 23 Oct 2014 10:00:02 +0000 This study was conducted to obtain the basic data of two common odorants—geosmin and 2-methylisoborneol (GSM and 2-MIB)—in environmental water. More specifically, the headspace solid-phase microextraction coupled to gas chromatography mass spectrometry (HS-SPME/GC-MS) was applied to determine the levels of GSM and 2-MIB in water samples, and the samples were collected depending on water sources, conventional treatment processes, and seasons. The significant difference was shown for the 2-MIB levels of source water , the concentrations of GSM and 2-MIB decreased significantly as treatment process of tap water moved forward , and the significant differences for the levels of GSM and 2-MIB were observed among three sampling periods . The levels of GSM and 2-MIB in all water samples were lower than 10 ng L−1, the odor threshold concentration (OTC), and the conventional treatment process plays a significant role in removing odorants in tap water. Zhen Ding, Shifu Peng, Yuqin Jin, Zhoubin Xuan, Xiaodong Chen, and Lihong Yin Copyright © 2014 Zhen Ding et al. All rights reserved. Isolation and Bioactivity Analysis of Ethyl Acetate Extract from Acer tegmentosum Using In Vitro Assay and On-Line Screening HPLC-ABTS+ System Wed, 15 Oct 2014 06:14:01 +0000 The Acer tegmentosum (3 kg) was extracted using hot water, and the freeze-dried extract powder was partitioned successively using dichloromethane (DCM), ethyl acetate (EA), butyl alcohol (n-BuOH), and water. From the EA extract fraction (1.24 g), five phenolic compounds were isolated by the silica gel, octadecyl silica gel, and Sephadex LH-20 column chromatography. Based on spectroscopic methods such as 1H-NMR, 13C-NMR, and LC/MS the chemical structures of the compounds were confirmed as feniculin (1), avicularin (2), (+)-catechin (3), (−)-epicatechin (4), and 6′-O-galloyl salidroside (5). Moreover, a rapid on-line screening HPLC-ABTS+ system for individual bioactivity of the EA-soluble fraction (five phenolic compounds) was developed. The results indicated that compounds 1 and 2 were first isolated from the A. tegmentosum. The anti-inflammatory activities and on-line screening HPLC-ABTS+ assay method of these compounds in LPS-stimulated murine macrophages were rapid and efficient for the investigation of bioactivity of A. tegmentosum. Kwang Jin Lee, Na-Young Song, You Chang Oh, Won-Kyung Cho, and Jin Yeul Ma Copyright © 2014 Kwang Jin Lee et al. All rights reserved. A Stability-Indicating HPLC-DAD Method for Determination of Stiripentol: Development, Validation, Kinetics, Structure Elucidation and Application to Commercial Dosage Form Tue, 14 Oct 2014 00:00:00 +0000 A rapid, simple, sensitive, and accurate isocratic reversed-phase stability-indicating high performance liquid chromatography method has been developed and validated for the determination of stiripentol and its degradation product in its bulk form and pharmaceutical dosage form. Chromatographic separation was achieved on a Symmetry C18 column and quantification was achieved using photodiode array detector (DAD). The method was validated in accordance with the ICH requirements showing specificity, linearity (, range of 1–25 μg/mL), precision (relative standard deviation lower than 2%), accuracy (mean recovery ), limits of detection and quantitation (LOD = 0.024 and LOQ = 0.081 μg/mL), and robustness. Stiripentol was subjected to various stress conditions and it has shown marked stability under alkaline hydrolytic stress conditions, thermal, oxidative, and photolytic conditions. Stiripentol degraded only under acidic conditions, forming a single degradation product which was well resolved from the pure drug with significantly different retention time values. This degradation product was characterized by 1H-NMR and 13C-NMR spectroscopy as well as ion trap mass spectrometry. The results demonstrated that the method would have a great value when applied in quality control and stability studies for stiripentol. Hany W. Darwish, Ali S. Abdelhameed, Mohamed I. Attia, Ahmed H. Bakheit, Nasr Y. Khalil, and Abdulrahman A. Al-Majed Copyright © 2014 Hany W. Darwish et al. All rights reserved. Content Determination of Active Component in Huangqi Yinyanghuo Group and Its Effects on hTERT and Bcl-2 Protein in Osteosarcoma Mon, 13 Oct 2014 08:25:03 +0000 To screen the optimal extraction process and content determination of active component of Huangqi Yinyanghuo group (HYG) and to study the effects of HYG on human telomerase reverse transcriptase (hTERT) and Bcl-2 protein in osteosarcoma (HOS) cells, providing the theoretical basis for clinical application of HYG in treatment of osteosarcoma, orthogonal design table L9(43) was used to design the extraction process of HYG, and icariin was taken as the investigation index to optimize the extraction process of HYG. 0.125, 0.25, 0.5, 1, 2, 4, and 8 μmol/L HYG were taken to act separately on logarithmic growth phase osteosarcoma HOS cells, CCK-8 assay was used to determine cell viability, and immunohistochemical SP assay was used to determine the expression of hTERT and Bcl-2 protein. Apoptosis rate was positively correlated with the dose of HYG, and the expressions of hTERT and Bcl-2 protein were significantly decreased with the prolonged duration of action. Under the effect of HYG, dose was negatively correlated with osteosarcoma cell survival fraction; osteosarcoma cell survival fraction was positively correlated with hTERT and Bcl-2 protein; duration of action was negatively correlated with hTERT and Bcl-2 protein; and hTERT and Bcl-2 protein were in a synchronous relationship. Ying Tan, Lei Tan, Shuai Huang, Junfan Lu, and Longtan Yu Copyright © 2014 Ying Tan et al. All rights reserved. Development of a Univariate Membrane-Based Mid-Infrared Method for Protein Quantitation and Total Lipid Content Analysis of Biological Samples Mon, 13 Oct 2014 08:11:56 +0000 Biological samples present a range of complexities from homogeneous purified protein to multicomponent mixtures. Accurate qualification of such samples is paramount to downstream applications. We describe the development of an MIR spectroscopy-based analytical method offering simultaneous protein quantitation (0.25–5 mg/mL) and analysis of total lipid or detergent species, as well as the identification of other biomolecules present in biological samples. The method utilizes a hydrophilic PTFE membrane engineered for presentation of aqueous samples in a dried format compatible with fast infrared analysis. Unlike classical quantification techniques, the reported method is amino acid sequence independent and thus applicable to complex samples of unknown composition. By comparison to existing platforms, this MIR-based method enables direct quantification using minimal sample volume (2 µL); it is well-suited where repeat access and limited sample size are critical parameters. Further, accurate results can be derived without specialized training or knowledge of IR spectroscopy. Overall, the simplified application and analysis system provides a more cost-effective alternative to high-throughput IR systems for research laboratories with minimal throughput demands. In summary, the MIR-based system provides a viable alternative to current protein quantitation methods; it also uniquely offers simultaneous qualification of other components, notably lipids and detergents. Ivona Strug, Christopher Utzat, Amedeo Cappione III, Sara Gutierrez, Ryan Amara, Joseph Lento, Florian Capito, Romas Skudas, Elena Chernokalskaya, and Timothy Nadler Copyright © 2014 Ivona Strug et al. All rights reserved. Development and Optimization of an UPLC-QTOF-MS/MS Method Based on an In-Source Collision Induced Dissociation Approach for Comprehensive Discrimination of Chlorogenic Acids Isomers from Momordica Plant Species Wed, 10 Sep 2014 11:27:07 +0000 Chlorogenic acids (CGA) have been profiled in the leaves of Momordica balsamina, Momordica charantia, and Momordica foetida. All three species were found to contain the trans and cis isomers of 4-acyl para-coumaroylquinic acid (pCoQA), caffeoylquinic acid (CQA), and feruloylquinic acid (FQA). To the best of our knowledge, this is the first report of pCoQA and FQA and their cis isomers in these Momordica species. These profiles were obtained by a newly developed UPLC-qTOF-MS method based on the in-source collision induced dissociation (ISCID) method optimized to mimic the MS2 and MS3 fragmentation of an ion trap-based MS. The presence of the cis isomers is believed to be due to high UV exposure of these plants. Furthermore, the absence of the 3-acyl and 5-acyl CGA molecules points to a metabolic mark that is unusual and represents a very interesting biochemical phenotype of these species. Our optimized ISCID method was also shown to be able to distinguish between the geometrical isomers of all three forms of CGA, a phenomenon previously deemed impossible with other common mass spectrometry systems used for CGA analyses. N. E. Madala, F. Tugizimana, and P. A. Steenkamp Copyright © 2014 N. E. Madala et al. All rights reserved. Validated Method for the Determination of Piroxicam by Capillary Zone Electrophoresis and Its Application to Tablets Tue, 09 Sep 2014 08:10:19 +0000 Simple and rapid capillary zone electrophoretic method was developed and validated in this study for the determination of piroxicam in tablets. The separation of piroxicam was conducted in a fused-silica capillary by using 10 mM borate buffer (pH 9.0) containing 10% (v/v) methanol as background electrolyte. The optimum conditions determined were 25 kV for separation voltage and 1 s for injection time. Analysis was carried out with UV detection at 204 nm. Naproxen sodium was used as an internal standard. The method was linear over the range of 0.23–28.79 µg/mL. The accuracy and precision were found to be satisfied within the acceptable limits (<2%). The LOD and LOQ were found to be 0.07 and 0.19 µg/mL, respectively. The method described here was applied to tablet dosage forms and the content of a tablet was found in the limits of USP-24 suggestions. To compare the results of capillary electrophoretic method, UV spectrophotometric method was developed and the difference between two methods was found to be insignificant. The capillary zone electrophoretic method developed in this study is rapid, simple, and suitable for routine analysis of piroxicam in pharmaceutical tablets. Arın Gül Dal, Zeynep Oktayer, and Dilek Doğrukol-Ak Copyright © 2014 Arın Gül Dal et al. All rights reserved. A Comparative Study of Newly Developed HPLC-DAD and UHPLC-UV Assays for the Determination of Posaconazole in Bulk Powder and Suspension Dosage Form Wed, 03 Sep 2014 00:00:00 +0000 Objective. To develop and compare HPLC-DAD and UHPLC-UV assays for the quantitation of posaconazole in bulk powder and suspension dosage form. Methods. Posaconazole linearity range was 5–50 μg/mL for both assays. For HPLC-DAD assay, samples were injected through Zorbax SB-C18 (4.6 × 250 mm, 5 μm) column. The gradient elution composed of the mobile phase acetonitrile: 15 mM potassium dihydrogen orthophosphate (30 : 70 to 80 : 20, linear over 7 minutes) pumped at 1.5 mL/min. For UHPLC-UV assay, samples were injected through Kinetex-C18 (2.1 × 50 mm, 1.3 μm) column. The mobile phase composed of acetonitrile: 15 mM potassium dihydrogen orthophosphate (45 : 55) pumped isocratically at 0.4 mL/min. Detection wavelength was 262 nm in both methods. Results. The run time was 11 and 3 minutes for HPLC-DAD and UHPLC-UV assays, respectively. Both assays were linear () with CV% and % error of the mean <3%. Limits of detection and quantitation were 0.82 and 2.73 μg/mL for HPLC-DAD and 1.04 and 3.16 μg/mL for UHPLC-UV, respectively. The methods quantitated PSZ in suspension dosage form with no observable interferences. Conclusions. Both assays were proven sensitive and selective according to ICH guidelines. UHPLC-UV assay exhibited some economic and chromatographic separation superiority. Dalia A. Hamdy and Tarek S. Belal Copyright © 2014 Dalia A. Hamdy and Tarek S. Belal. All rights reserved. Quantification of Neurotransmitters in Mouse Brain Tissue by Using Liquid Chromatography Coupled Electrospray Tandem Mass Spectrometry Wed, 03 Sep 2014 00:00:00 +0000 A simple and rapid liquid chromatography tandem mass spectrometry method has been developed for the determination of BH4, DA, 5-HT, NE, EP, Glu, and GABA in mouse brain using epsilon-acetamidocaproic acid and isotopically labeled neurotransmitters as internal standards. Proteins in the samples were precipitated by adding acetonitrile, and then the supernatants were separated by a Sepax Polar-Imidazole (2.1 mm × 100 mm, i.d., 3 μm) column by adding a mixture of 10 mM ammonium formate in acetonitrile/water (75 : 25, v/v, 300 μl/min) for BH4 and DA. To assay 5-HT, NE, EP, Glu, and GABA; a Luna 3 μ C18 (3.0 mm × 150 mm, i.d., 3 μm) column was used by adding a mixture of 1% formic acid in acetonitrile/water (20 : 80, v/v, 350 μl/min). The total chromatographic run time was 5.5 min. The method was validated for the analysis of samples. The calibration curve was linear between 10 and 2000 ng/g for BH4 , 10 and 5000 ng/g for DA , 20 and 10000 ng/g for 5-HT , NE , and EP , and 0.2 and 200 μg/g for Glu and GABA in the mouse brain tissues. As stated above, LC-MS/MS results were obtained and established to be a useful tool for the quantitative analysis of BH4, DA, 5-HT, NE, EP, Glu, and GABA in the experimental rodent brain. Tae-Hyun Kim, Juhee Choi, Hyung-Gun Kim, and Hak Rim Kim Copyright © 2014 Tae-Hyun Kim et al. All rights reserved. Extraction and Bioactivity Analysis of Major Flavones Compounds from Scutellaria baicalensis Using In Vitro Assay and Online Screening HPLC-ABTS System Mon, 01 Sep 2014 00:00:00 +0000 The extraction efficiency of a number of solvent compositions for the improvement of bioactive compounds yield from S. baicalensis has been investigated. Also, free radical scavengers in the glycoside baicalin (BG), wogonoside (WG), aglycon baicalein (B), and wogonin (W) compounds of S. baicalensis were screened, identified, and quantified using coupled offline ABTS and online screening HPLC-ABTS assay. Increasing ethanol content fractions resulted in decreased extract yield of bioactive compounds. In this case, the best yield of 37.01 mg/g in BG, WG, B, and W compounds was obtained by a dipping method with an extraction time of 4 h. In addition, the yield (43.05%) and IC50 (34.04 μg/mL) determined through ABTS assay of the 60% aqueous ethanol extract were the most satisfactory of all solvent solutions tested. This result shows that an online screening HPLC-ABTS assay can be a powerful technique for the rapid characterization of bioactivity compounds in plant extracts. Moreover, their anti-inflammatory activities were evaluated via analyzed inhibitory effect on NO and inflammatory cytokine production. Furthermore, WG and W exhibited the strong inhibitory effects on inflammatory mediator production including NO, IL-6, and IL-1β in LPS-stimulated RAW 264.7 macrophages. Kwang Jin Lee, Pil Mun Jung, You-Chang Oh, Na-Young Song, Taesoo Kim, and Jin Yeul Ma Copyright © 2014 Kwang Jin Lee et al. All rights reserved. Global Clustering Quality Coefficient Assessing the Efficiency of PCA Class Assignment Tue, 26 Aug 2014 00:00:00 +0000 An essential factor influencing the efficiency of the predictive models built with principal component analysis (PCA) is the quality of the data clustering revealed by the score plots. The sensitivity and selectivity of the class assignment are strongly influenced by the relative position of the clusters and by their dispersion. We are proposing a set of indicators inspired from analytical geometry that may be used for an objective quantitative assessment of the data clustering quality as well as a global clustering quality coefficient (GCQC) that is a measure of the overall predictive power of the PCA models. The use of these indicators for evaluating the efficiency of the PCA class assignment is illustrated by a comparative study performed for the identification of the preprocessing function that is generating the most efficient PCA system screening for amphetamines based on their GC-FTIR spectra. The GCQC ranking of the tested feature weights is explained based on estimated density distributions and validated by using quadratic discriminant analysis (QDA). Mirela Praisler and Stefanut Ciochina Copyright © 2014 Mirela Praisler and Stefanut Ciochina. All rights reserved. Electrochemical Study of Ni20Cr Coatings Applied by HVOF Process in ZnCl2-KCl at High Temperatures Mon, 25 Aug 2014 11:05:34 +0000 Corrosion behavior of Ni20Cr coatings deposited by HVOF (high velocity oxygen-fuel) process was evaluated in ZnCl2-KCl (1 : 1 mole ratio) molten salts. Electrochemical techniques employed were potentiodynamic polarization curves, open circuit potential, and linear polarization resistance (LPR) measurements. Experimental conditions included static air and temperatures of 350, 400, and 450°C. 304-type SS was evaluated in the same conditions as the Ni20Cr coatings and it was used as a reference material to assess the coatings corrosion resistance. Coatings were evaluated as-deposited and with a grinded surface finished condition. Results showed that Ni20Cr coatings have a better corrosion performance than 304-type SS. Analysis showed that Ni content of the coatings improved its corrosion resistance, and the low corrosion resistance of 304 stainless steel was attributed to the low stability of Fe and Cr and their oxides in the corrosive media used. J. Porcayo-Calderón, O. Sotelo-Mazón, M. Casales-Diaz, J. A. Ascencio-Gutierrez, V. M. Salinas-Bravo, and L. Martinez-Gomez Copyright © 2014 J. Porcayo-Calderón et al. All rights reserved. Alkaloids in Processed Rhizoma Corydalis and Crude Rhizoma Corydalis Analyzed by GC/MS Mon, 25 Aug 2014 07:39:54 +0000 The alkaloids in the processed Rhizoma Corydalis and the crude Rhizoma Corydalis were qualitatively and semiquantitatively analyzed using gas chromatography-mass spectrometry (GC/MS) method. The processing herb drug procedure was carried out according to the standard method of Chinese Pharmacopoeia. The samples were extracted using Soxhlet extractor with different solvents: methanol and acetone. The extraction effect on different solvents was investigated. The results showed that 11 kinds of alkaloids were identified from the crude Rhizoma Corydalis and only two were from the processed Rhizoma Corydalis. A total of 13 kinds of alkaloids were all based on two backbones. The alkaloids in the processed sample were less than those in the crude Rhizoma Corydalis significantly, while almost the corydaline has been changed in conformation after the sample had undergone processing, which provided support for the conclusion of reducing toxicity when the herbal medicine having been undergone a traditional drugs treatment process. Zhifeng Guo, Ru Cai, Huidan Su, and Yunlong Li Copyright © 2014 Zhifeng Guo et al. All rights reserved. Quality Control of Natural Product Medicine and Nutrient Supplements 2014 Thu, 21 Aug 2014 09:38:39 +0000 Ying-Yong Zhao, Shuang-Qing Zhang, Feng Wei, Yu-Ming Fan, Feng Sun, and Shuhua Bai Copyright © 2014 Ying-Yong Zhao et al. All rights reserved. Stacking and Analysis of Melamine in Milk Products with Acetonitrile-Salt Stacking Technique in Capillary Electrophoresis Mon, 18 Aug 2014 00:00:00 +0000 Melamine was measured in real milk products with capillary electrophoresis (CE) based on acetonitrile-salt stacking (ASS) method. Real milk samples were deproteinized with acetonitrile at a final concentration of 60% (v/v) and then injected hydrodynamically at 50 mBar for 40.0 s. The optimized buffer contains 80.0 mmol/L pH 2.8 phosphates. Melamine could be detected within 20.0 min at +10 kV with a low limit of detection (LOD) of 0.03 μmol/L. Satisfactory reproducibility (inter- and intraday RSD% both for migration time and peak area was lower than 5.0%) and a wide linearity range of 0.05 μmol/L ~ 10.0 μmol/L were achieved. The proposed method was suitable for routine assay of MEL in real milk samples that was subjected to a simple treatment step. Yu Kong, Chong Wei, Zhanwu Hou, Zilong Wang, Jiaqiang Yuan, Jiang Yu, Yongxi Zhao, Yuhai Tang, and Meili Gao Copyright © 2014 Yu Kong et al. All rights reserved. Determination of Flavanones in Orange Juices Obtained from Different Sources by HPLC/DAD Thu, 07 Aug 2014 10:56:09 +0000 Flavanones (hesperidin, naringenin, naringin, and poncirin) in industrial, hand-squeezed orange juices and from fresh-in-squeeze machines orange juices were determined by HPLC/DAD analysis using a previously described liquid-liquid extraction method. Method validation including the accuracy was performed by using recovery tests. Samples (36) collected from different Brazilian locations and brands were analyzed. Concentrations were determined using an external standard curve. The limits of detection (LOD) and the limits of quantification (LOQ) calculated were 0.0037, 1.87, 0.0147, and 0.0066 mg 100 g−1 and 0.0089, 7.84, 0.0302, and 0.0200 mg 100 g−1 for naringin, hesperidin, poncirin, and naringenin, respectively. The results demonstrated that hesperidin was present at the highest concentration levels, especially in the industrial orange juices. Its average content and concentration range were 69.85 and 18.80–139.00 mg 100 g−1. The other flavanones showed the lowest concentration levels. The average contents and concentration ranges found were 0.019, 0.01–0.30, and 0.12 and 0.1–0.17, 0.13, and 0.01–0.36 mg 100 g−1, respectively. The results were also evaluated using the principal component analysis (PCA) multivariate analysis technique which showed that poncirin, naringenin, and naringin were the principal elements that contributed to the variability in the sample concentrations. Lidércia C. R. Cerqueira e Silva, Jorge M. David, Rafael dos S. Q. Borges, Sérgio L. C. Ferreira, Juceni P. David, Pedro S. dos Reis, and Roy E. Bruns Copyright © 2014 Lidércia C. R. Cerqueira e Silva et al. All rights reserved. The Therapeutic Effect of Zuogui Wan in Gestational Diabetes Mellitus Rats Tue, 22 Jul 2014 08:59:48 +0000 In this experiment, we established an animal model of gestational diabetes mellitus rats using streptozotocin. Using the rat model of GDM, the pregnant rats in 1-19d were divided into three groups: (1) Zuogui Wan gestational diabetes mellitus group (group I, ). Compared with gestational diabetes mellitus rats as the control group, Zuogui Wan can change the indexes of fasting blood glucose, body weight, total cholesterol, insulin, and metabolism cage index significantly in Zuogui Wan gestational diabetes mellitus group. We can conclude that Zuogui Wan has the therapeutic effect on gestational diabetes mellitus. Yuwei Wang, Qianjin Feng, Xin Niu, Xinshe Liu, Kaixia Xu, Xiangzhu Yang, Huifeng Wang, and Qiuju Li Copyright © 2014 Yuwei Wang et al. All rights reserved. Quantitative Analysis of Adulterations in Oat Flour by FT-NIR Spectroscopy, Incomplete Unbalanced Randomized Block Design, and Partial Least Squares Sun, 20 Jul 2014 11:51:04 +0000 This paper developed a rapid and nondestructive method for quantitative analysis of a cheaper adulterant (wheat flour) in oat flour by NIR spectroscopy and chemometrics. Reflectance FT-NIR spectra in the range of 4000 to 12000 cm−1 of 300 oat flour objects adulterated with wheat flour were measured. The doping levels of wheat flour ranged from 5% to 50% (w/w). To ensure the generalization performance of the method, both the oat and the wheat flour samples were collected from different producing areas and an incomplete unbalanced randomized block (IURB) design was performed to include the significant variations that may be encountered in future samples. Partial least squares regression (PLSR) was used to develop calibration models for predicting the levels of wheat flour. Different preprocessing methods including smoothing, taking second-order derivative (D2), and standard normal variate (SNV) transformation were investigated to improve the model accuracy of PLS. The root mean squared error of Monte Carlo cross-validation (RMSEMCCV) and root mean squared error of prediction (RMSEP) were 1.921 and 1.975 (%, w/w) by D2-PLS, respectively. The results indicate that NIR and chemometrics can provide a rapid method for quantitative analysis of wheat flour in oat flour. Ning Wang, Xingxiang Zhang, Zhuo Yu, Guodong Li, and Bin Zhou Copyright © 2014 Ning Wang et al. All rights reserved. Automated System for Kinetic Analysis of Particle Size Distributions for Pharmaceutically Relevant Systems Wed, 16 Jul 2014 14:15:37 +0000 Detailing the kinetics of particle formation for pharmaceutically relevant solutions is challenging, especially when considering the combination of formulations, containers, and timescales of clinical importance. This paper describes a method for using commercial software Automate with a stream-selector valve capable of sampling container solutions from within an environmental chamber. The tool was built to monitor changes in particle size distributions via instrumental particle counters but can be adapted to other solution-based sensors. The tool and methodology were demonstrated to be highly effective for measuring dynamic changes in emulsion globule distributions as a function of storage and mixing conditions important for parenteral nutrition. Higher levels of agitation induced the fastest growth of large globules (≥5 μm) while the gentler conditions actually showed a decrease in the number of these large globules. The same methodology recorded calcium phosphate precipitation kinetics as a function of [Ca2+] and pH. This automated system is readily adaptable to a wide range of pharmaceutically relevant systems where the particle size is expected to vary with time. This instrumentation can dramatically reduce the time and resources needed to probe complex formulation issues while providing new insights for monitoring the kinetics as a function of key variables. John-Bruce D. Green, Phillip W. Carter, Yingqing Zhang, Dipa Patel, Priyanka Kotha, and Thomas Gonyon Copyright © 2014 John-Bruce D. Green et al. All rights reserved. Rapid Discrimination of the Geographical Origins of an Oolong Tea (Anxi-Tieguanyin) by Near-Infrared Spectroscopy and Partial Least Squares Discriminant Analysis Thu, 26 Jun 2014 00:00:00 +0000 This paper focuses on a rapid and nondestructive way to discriminate the geographical origin of Anxi-Tieguanyin tea by near-infrared (NIR) spectroscopy and chemometrics. 450 representative samples were collected from Anxi County, the original producing area of Tieguanyin tea, and another 120 Tieguanyin samples with similar appearance were collected from unprotected producing areas in China. All these samples were measured by NIR. The Stahel-Donoho estimates (SDE) outlyingness diagnosis was used to remove the outliers. Partial least squares discriminant analysis (PLSDA) was performed to develop a classification model and predict the authenticity of unknown objects. To improve the sensitivity and specificity of classification, the raw data was preprocessed to reduce unwanted spectral variations by standard normal variate (SNV) transformation, taking second-order derivatives (D2) spectra, and smoothing. As the best model, the sensitivity and specificity reached 0.931 and 1.000 with SNV spectra. Combination of NIR spectrometry and statistical model selection can provide an effective and rapid method to discriminate the geographical producing area of Anxi-Tieguanyin. Si-Min Yan, Jun-Ping Liu, Lu Xu, Xian-Shu Fu, Hai-Feng Cui, Zhen-Yu Yun, Xiao-Ping Yu, and Zi-Hong Ye Copyright © 2014 Si-Min Yan et al. All rights reserved. Quantification of Photocyanine in Human Serum by High-Performance Liquid Chromatography-Tandem Mass Spectrometry and Its Application in a Pharmacokinetic Study Tue, 24 Jun 2014 00:00:00 +0000 Photocyanine is a novel anticancer drug. Its pharmacokinetic study in cancer patients is therefore very important for choosing doses, and dosing intervals in clinical application. A rapid, selective and sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed and validated for the determination of photocyanine in patient serum. Sample preparation involved one-step protein precipitation by adding methanol and N,N-dimethyl formamide to 0.1 mL serum. The detection was performed on a triple quadrupole tandem mass spectrometer operating in multiple reaction-monitoring (MRM) mode. Each sample was chromatographed within 7 min. Linear calibration curves were obtained for photocyanine at a concentration range of 20–2000 ng/mL (), with the lower limit of quantification (LLOQ) being 20 ng/mL. The intrabatch accuracy ranged from 101.98% to 107.54%, and the interbatch accuracy varied from 100.52% to 105.62%. Stability tests showed that photocyanine was stable throughout the analytical procedure. This study is the first to utilize the HPLC-MS/MS method for the pharmacokinetic study of photocyanine in six cancer patients who had received a single dose of photocyanine (0.1 mg/kg) administered intravenously. Bing-Tian Bi, Ben-Yan Zou, Li-Ting Deng, Jing Zhan, Hai Liao, Kun-Yao Feng, and Su Li Copyright © 2014 Bing-Tian Bi et al. All rights reserved. Quasireversible Process of Dopamine on Copper-Nickel Hydroxide Composite/Nitrogen Doped Graphene/Nafion Modified GCE and Its Electrochemical Application Mon, 16 Jun 2014 12:21:11 +0000 Cu-Ni(OH)2/N-GR/Nafion/GCE has been prepared by electrodeposition and activation with NaOH. The proposed modified GCE was studied by electrochemical methods. It is found that dopamine shows favorable redox cyclic voltammetric response on the proposed modified GCE with peak separation of 25 mV and large current compared with on single-component modified GCE. The kinetic of electrode process has also been investigated with rate constant of 6.618 × 10−3 cm/s, which can be deduced to be a quasireversible or near-reversible process. The proposed method has been used for DA detection with linear range of 1.0 × 10−7 mol/L to 4.6 × 10−5 mol/L, and the detection limit is 3.3 × 10−8 mol/L. The proposed method has favorable stability and reproducibility and has also been used to determine DA in simulated samples and DA injections with favorable recoveries of 98.4% to 102.6%. Chuan-yin Liu, Zhong-yong Liu, Rong Peng, and Zhi-cheng Zhong Copyright © 2014 Chuan-yin Liu et al. All rights reserved. Chemistry of Medicinal Plants, Foods, and Natural Products Wed, 04 Jun 2014 09:29:37 +0000 Shixin Deng, Shao-Nong Chen, and Jian Yang Copyright © 2014 Shixin Deng et al. All rights reserved. Study on the Effect of Electrochemical Dechlorination Reduction of Hexachlorobenzene Using Different Cathodes Wed, 04 Jun 2014 06:51:24 +0000 Hexachlorobenzene (HCB) is a persistent organic pollutant and poses great threat on ecosystem and human health. In order to investigate the degradation law of HCB, a RuO2/Ti material was used as the anode, meanwhile, zinc, stainless steel, graphite, and RuO2/Ti were used as the cathode, respectively. The gas chromatography (GC) was used to analyze the electrochemical products of HCB on different cathodes. The results showed that the cathode materials significantly affected the dechlorination efficiency of HCB, and the degradation of HCB was reductive dechlorination which occurred only on the cathode. During the reductive process, chlorine atoms were replaced one by one on various intermediates such as pentachlorobenzene, tetrachlorobenzene, and trichlorobenzene occurred; the trichlorobenzene was obtained when zinc was used as cathode. The rapid dechlorination of HCB suggested that the electrochemical method using zinc or stainless steel as cathode could be used for remediation of polychlorinated aromatic compounds in the environment. The dechlorination approach of HCB by stainless steel cathode could be proposed. Yingru Wang and Xiaohua Lu Copyright © 2014 Yingru Wang and Xiaohua Lu. All rights reserved. Comparability of a Three-Dimensional Structure in Biopharmaceuticals Using Spectroscopic Methods Thu, 22 May 2014 15:47:29 +0000 Protein structure depends on weak interactions and covalent bonds, like disulfide bridges, established according to the environmental conditions. Here, we present the validation of two spectroscopic methodologies for the measurement of free and unoxidized thiols, as an attribute of structural integrity, using 5,5′-dithionitrobenzoic acid (DTNB) and DyLight Maleimide (DLM) as derivatizing agents. These methods were used to compare Rituximab and Etanercept products from different manufacturers. Physicochemical comparability was demonstrated for Rituximab products as DTNB showed no statistical differences under native, denaturing, and denaturing-reducing conditions, with Student’s -test values of 0.6233, 0.4022, and 0.1475, respectively. While for Etanercept products no statistical differences were observed under native () and denaturing conditions (), denaturing-reducing conditions revealed cysteine contents of 98% and 101%, towards the theoretical value of 58, for the evaluated products from different Etanercept manufacturers. DLM supported equality between Rituximab products under native () and denaturing conditions (), but showed statistical differences among Etanercept products under native conditions (). DLM suggested that Infinitam has fewer exposed thiols than Enbrel, although DTNB method, circular dichroism (CD), fluorescence (TCSPC), and activity (TNFα neutralization) showed no differences. Overall, this data revealed the capabilities and drawbacks of each thiol quantification technique and their correlation with protein structure. Víctor Pérez Medina Martínez, Mario E. Abad-Javier, Alexis J. Romero-Díaz, Francisco Villaseñor-Ortega, Néstor O. Pérez, Luis F. Flores-Ortiz, and Emilio Medina-Rivero Copyright © 2014 Víctor Pérez Medina Martínez et al. All rights reserved. Simultaneous Quantification of Ten Active Components in Traditional Chinese Formula Sijunzi Decoction Using a UPLC-PDA Method Tue, 20 May 2014 06:38:05 +0000 Sijunzi decoction (SJZT), a traditional Chinese formula (TCMF) consisting of four herbs, has been widely used for the treatment of various gastrointestinal symptoms. However, its modernization process is hindered by the lack of a powerful quality control method that covers the major active components in the formula. The aim of this study was to establish a UPLC method for the quantitative determination of ten active components in Sijunzi decoction including ginsenoside Rg1, Re, Rb1, liquiritin, liquiritigenin, glycyrrhizic acid, atractylenolide I, atractylenolide II, atractylenolide III, and pachymic acid. Separation was achieved using an ACQUITY UPLC BEHC18 column (2.1 mm × 100 mm, 1.7 μm) with a gradient elution program consisting of acetonitrile and 0.1% phosphoric acid solution. The detection wavelengths were set at 203, 254, 222, and 267 nm. The method was validated for linearity, accuracy, precision, limit of detection, and limit of quantification. The validated method was successfully applied to the simultaneous quantification of ten active compounds from several finished batches of SJZT. This validated that UPLC method is expected to provide a new basis for the quality control of SJZT. Kang An, Guo Jin-rui, Zhang Zhen, and Wang Xiao-long Copyright © 2014 Kang An et al. All rights reserved. Ultrasensitive Detection of Ferulic Acid Using Poly(diallyldimethylammonium chloride) Functionalized Graphene-Based Electrochemical Sensor Mon, 12 May 2014 14:13:14 +0000 The electrochemical redox of ferulic acid (FA) was investigated systematically by cyclic voltammetry (CV) with a poly(diallyldimethylammonium chloride) functionalized graphene-modified glassy carbon electrode (PDDA-G/GCE) as a working electrode. A simple and sensitive differential pulse voltammetry (DPV) technique was proposed for the direct quantitative determination of FA in Angelica sinensis and spiked human urine samples for the first time. The dependence of the intensities of currents and potentials on nature of the supporting electrolyte, pH, scan rate, and concentration was investigated. Under optimal conditions, the proposed sensor exhibited excellent electrochemical sensitivity to FA, and the oxidation peak current was proportional to FA concentration in the range of  M  M, with a relatively low detection limit of  M. This fabricated sensor also displayed acceptable reproducibility, long-term stability, and high selectivity with negligible interferences from common interfering species. Besides, it was applied to detect FA in Angelica sinensis and biological samples with satisfactory results, making it a potential alternative tool for the quantitative detection of FA in pharmaceutical analysis. Lin-jie Liu, Xia Gao, Pei Zhang, Shi-lan Feng, Fang-di Hu, Ying-dong Li, and Chun-ming Wang Copyright © 2014 Lin-jie Liu et al. All rights reserved. Quantitative Analysis of Panax ginseng by FT-NIR Spectroscopy Mon, 05 May 2014 07:16:07 +0000 Near-infrared spectroscopy (NIRS), a rapid and efficient tool, was used to determine the total amount of nine ginsenosides in Panax ginseng. In the study, the regression models were established using multivariate regression methods with the results from conventional chemical analytical methods as reference values. The multivariate regression methods, partial least squares regression (PLSR) and principal component regression (PCR), were discussed and the PLSR was more suitable. Multiplicative scatter correction (MSC), second derivative, and Savitzky-Golay smoothing were utilized together for the spectral preprocessing. When evaluating the final model, factors such as correlation coefficient (R2) and the root mean square error of prediction (RMSEP) were considered. The final optimal results of PLSR model showed that root mean square error of prediction (RMSEP) and correlation coefficients (R2) in the calibration set were 0.159 and 0.963, respectively. The results demonstrated that the NIRS as a new method can be applied to the quality control of Ginseng Radix et Rhizoma. Xin-fang Xu, Li-xing Nie, Li-li Pan, Bian Hao, Shao-xiong Yuan, Rui-chao Lin, Hai-bo Bu, Dan Wang, Ling Dong, and Xiang-ri Li Copyright © 2014 Xin-fang Xu et al. All rights reserved. Electrochemical Immunoassay of Escherichia coli O157:H7 Using Ag@SiO2 Nanoparticles as Labels Sun, 27 Apr 2014 13:21:09 +0000 Silica coated silver (Ag@SiO2) nanoparticles were prepared and characterized by transmission electron microscope (TEM) and UV-vis absorption, and the nanoparticles were used as labels in sandwich-type immunosensor of Escherichia coli O157:H7 (E. coli O157:H7). The labels involved in immunoreaction were dissolved by mixed acid of hydrofluoric acid and nitric acid, and the released Ag+ ions were electrochemical stripping analyzed (via differential pulse voltammetry, DPV) at poly(acrylic acid)/poly(diallyldimethylammonium chloride)/carbon nanotubes (PAA/PDCNT) modified glass carbon electrode (GCE), which obviously enhanced the signal of Ag+ stripping. Then, the number of E. coli O157:H7 could be indirectly reflected by the signal intensity of labeled Ag+. And the results showed that the DPV signals were proportional to the logarithm of the E. coli O157:H7 concentration in the range from 20 cfu/mL to  cfu/mL with the detection limit of 13 cfu/mL. Guang-Zhu Chen, Zheng-Zhi Yin, and Jv-Feng Lou Copyright © 2014 Guang-Zhu Chen et al. All rights reserved. Quantitative Analysis of Matrine in Liquid Crystalline Nanoparticles by HPLC Mon, 14 Apr 2014 16:19:44 +0000 A reversed-phase high-performance liquid chromatographic method has been developed to quantitatively determine matrine in liquid crystal nanoparticles. The chromatographic method is carried out using an isocratic system. The mobile phase was composed of methanol-PBS(pH6.8)-triethylamine (50 : 50 : 0.1%) with a flow rate of 1 mL/min with SPD-20A UV/vis detector and the detection wavelength was at 220 nm. The linearity of matrine is in the range of 1.6 to 200.0 μg/mL. The regression equation is (). The average recovery is 101.7%; %  (). This method provides a simple and accurate strategy to determine matrine in liquid crystalline nanoparticle. Xinsheng Peng, Baohong Li, Min Hu, Yahao Ling, Yuan Tian, Yanxing Zhou, and Yanfang Zhou Copyright © 2014 Xinsheng Peng et al. All rights reserved.