Classification and dating of black gel pen ink by ion-pairing high-performance liquid chromatography

A novel approach for classification and dating of the black gel pen ink entries on document was developed based on ion-pairing high-performance liquid chromatography (IP-HPLC). Ninety-three black gel pens were collected and divided into two groups, dye-based and pigment-based, by preliminary solubility test. The chromatographic conditions for separation of the dye-based black gel pen inks were optimized and the dye components in inks were satisfactorily separated by using 40 mmol/L tetrabutylammonium bromide as ion-pairing reagent. According to the number and the chromatographic retention times of the main dye components, the 50 dye-based inks were categorized into four classes. The inks within a class can be further identified by the percentage of each dye component. The compositional changes of the dye components in the black gel pen ink entries on paper were investigated in light and natural aging conditions and it has been found that the dye components in the ink entries underwent obvious decomposition, and the decomposing extent of the dye components was related to the aging time. The results can provide scientific evidences for dating of the suspicious black gel pen ink entries on documents.     

New aspects of determination of polymer heterogeneity by 2-Dimensional orthogonal liquid chromatography and maldi-tof- MS

Liquid Adsorption Chromatography at Critical Conditions (LACCC) of polymers in combination with Matrix-Assisted Laser Desorption / Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF-MS) and different types of detectors is a very convenient method for the characterization of polymer heterogeneities. A pathway for working out these methods is given. Additionally to the coupling of different chromatographic modes a device for post-column reaction detection is described and applied. Examples of applications are given for aliphatic and aromatic polyesters. MALDI-TOF-MS, reaction detection and relations between “critical” solvent composition and structure of polyesters are discussed. Conclusions concerning the mechanism of thermal degradation of polylactides are shown.     

Trends in surface and interface analysis

Summary The rapid progress in high technology constantly poses new challenges for Analytical Chemistry and prompts the development of new techniques and procedures. The influence is particularly strong in surface and interface analysis, which is developing at a rapid pace. This paper discusses some of the frontier areas like high-resolution depth-distribution analysis of trace elements, quantitative depth distribution analysis of ultra thin-layer systems, quantitative trace element analysis in monolayers, 3-dimensional stereometric analysis, molecular analysis, in-situ atomic resolution analysis of surfaces (chemical nanoscopy). Methodological approaches are discussed as well as results obtained mainly with solid state mass spectrometry and atomic force microscopy.Abbreviations and acronyms AES Auger Electron Spectrometry - AEM Analytical Electron Microscopy - AFM Atomic Force Microscopy - BSE Back Scattered Electrons - EPMA Electron Probe Micro Analysis - LRI-SNMS Laser Resonance Ionization Sputtered Neutrals Mass Spectrometry - SE Secondary Electrons - SEM Scanning Electron Microscopy - SIMS Secondary Ion Mass Spectrometry - STM Scanning Tunneling Microscopy - TEM Transmission Electron Microscopy - TOF-MS Time-of-Flight Mass Spectrometer - TXRF Total Reflection X-Ray Spectrometry - XPS X-Ray Photoelectron Spectroscopy Dedicated to Professor Dr. Wilhelm Fresenius on the occasion of his 80th birthday     

Forensic Identification of Dyes in Ballpoint Pen Inks Using LC–ESI–MS

The aim of this work was to develop a new technique using flow injection analysis combined with LC–ESI–MS which allows identification of dyes in ballpoint pen inks. A sample preparation procedure for the extraction of dyes from ballpoint pen strokes has been developed. The characteristic group of ions for each sample of 21 studied ballpoint pen inks corresponding to the present dyes has been determined using flow injection method. LC separation conditions for identified dyes have been optimized on reversed-phase sorbent based on silica gel. The best composition of the mobile phase for the dyes mixture LC separation was 0.1% aqueous formic acid and acetonitrile. Detection of dyes was carried out using mass spectrometry with electrospray ionization in positive and negative modes after reversed-phase liquid chromatography separation. Dye composition of ink was additionally confirmed comparing the data obtained from the literature. Flow injection analysis allows obtaining intensive ions of unknown strokes. It is difficult to get this information using only chromatographic methods, because dyes peak intensity can be low and noise of basic line high. Flow injection method allows distinguishing the analyzed 21 ballpoint pens by determining a characteristic set of dyes. The developed flow injection technique is very simple and quick. As a result, a novel approach for the identification of dyes in the ballpoint pen inks by flow injection analysis with LC–ESI–MS and UV detection without using standard dye samples has been established. It can be an effective alternative to the existing LC–DAD–MS and IR spectroscopy methods.     

Development and Validation of QuEChERS Followed by UHPLC-ToF-MS Method for Determination of Multi-Mycotoxins in Pistachio Nuts

Pistachios are one of the types of tree nut fruits with the highest mycotoxin contamination, especially of aflatoxins, worldwide. This study developed a Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method that was followed by Ultra-High Performance Liquid Chromatography combined with Time-of-Flight Mass Spectrometry (UHPLC–ToF-MS) for the determination of mycotoxins in pistachios. Different approaches to dispersive solid phase extraction as a clean-up method for high lipid matrices were evaluated. For this, classic sorbents such as C18 (octadecyl-modified silica) and PSA (primary secondary amine), and new classes of sorbents, namely EMR-Lipid (enhanced matrix removal-lipid) and Z-Sep (modified silica gel with zirconium oxide), were used. The QuEChERS method, followed by Z-Sep d-SPE clean-up, provided the best analytical performance for aflatoxins (AFB1, AFB2, AFG1 and AFG2), ochratoxin A (OTA), zearalenone (ZEA), toxin T2 (T2) and toxin HT-2 (HT2) in pistachios. The method was validated in terms of linearity, sensitivity, repeatability, interday precision and recovery; it achieved good results according to criteria imposed by Commission Regulation (EC) no. 401/2006. The method was applied to real samples and the results show that pistachios that are available in Portuguese markets are safe from mycotoxins that are of concern to human health.     

Study and characterization of mural paintings from XIX Century in a noble Venetian (Italy) palace

The present paper describes the characterization carried out on the roof of a private palace located in the historical center of Venice (Italy). We focused our attention on the studies of original constituent materials (pigments and binders), in order to identify the pictorial technique of the artist and verify the stylistic attribution to Giuseppe Borsato, a Venetian painter operating between 18th and 19th century. Characterization of collected samples was carried on using both conventional and advanced analytical techniques, such as Optical Microscopy and Scanning Electron Microscopy coupled with Energy Dispersive X-Ray (SEM–EDS) microscopy, Fourier Transform Infrared Spectroscopy (FTIR) and High Performance Liquid Chromatography (HPLC) coupled with photodiode array detection (DAD) and Mass Spectrometry (MS). The finding of dating pigments (such as Cobalt blue and Cu–As based green) and of a complex binding's mixture compatible with the considered supposed period, allowed us to confirm the attribution hypothesis.     

Magnetic Solid-Phase Extraction Based on Magnetic Sulfonated Reduced Graphene Oxide for HPLC–MS/MS Analysis of Illegal Basic Dyes in Foods

In this study, a magnetic solid-phase extraction (MSPE) method coupled with High-Performance Liquid Chromatography Mass Spectrometry (HPLC–MS/MS) for the determination of illegal basic dyes in food samples was developed and validated. This method was based on Magnetic sulfonated reduced graphene oxide (M-S-RGO), which was sensitive and selective to analytes with structure of multiaromatic rings and negatively charged ions. Several factors affecting MSPE efficiency such as pH and adsorption time were optimized. Under the optimum conditions, the calibration curves exhibited good linearity, ranging from 5 to 60 µg/g with correlation coefficients >0.9950. The limits of detection of 16 basic dyes were in the range of 0.01–0.2 µg/L. The recoveries ranged from 70% to 110% with RSD% < 10%. The results indicate that M-S-RGO is an efficient and selective adsorbent for the extraction and cleanup of basic dyes. Due to the MSPE procedures, matrix effect and interference were eliminated in the analysis of HPLC–MS/MS without the matrix-matched standards. Thus, validation data showed that the proposed MSPE–HPLC–MS/MS method was rapid, efficient, selective, and sensitive for the determination of illegal basic dyes in foods.     

Discrimination of prostate cancer cells and non-malignant cells using secondary ion mass spectrometry

This communication utilises Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) combined with multivariate analysis to obtain spectra from the surfaces of three closely related cell lines allowing their discrimination based upon mass spectral ions.     

Structural elucidation and estimation of the acute toxicity of the major UV–visible photoproduct of fludioxonil – detection in both skin and flesh samples of grape

Ultraviolet (UV)–visible irradiation of fludioxonil was investigated with two photoreactors using either a mercury or xenon vapor lamp. In both cases, it led to the formation of only one photoproduct in significant amount: 2‐(2,2‐difluorobenzo[d][1,3]dioxol‐4‐yl)‐2‐(nitrosomethylene)‐4‐oxobutanenitrile, which has been characterized using Liquid Chromatography ‐ High Resolution ‐ Tandem Mass Spectrometry (LC‐HR‐MS/MS) coupling. A photolysis pathway has been proposed to rationalize its formation in degassed water. In vitro bioassays on Vibrio fischeri bacteria showed that UV–vis irradiation of an aqueous solution of fludioxonil significantly increases its toxicity. Because no other by‐product was detected in significant amount, the photoproduct mentioned above may be considered mainly responsible for this increase in toxicity. Grape berries treated with a 50 ppm aqueous solution of fludioxonil were submitted to UV–visible irradiation under laboratory conditions. The fungicide and photoproduct were detected in both skin and flesh of berries, even after they have been rinsed with water. The ability of the photoproduct to pass through the fruit skin is comparable with that of fludioxonil. These results are of concern for consumers because they mean that water tap rinsing does not lead to efficient removing of both compounds. Copyright © 2015 John Wiley & Sons, Ltd.     

Studies on the degradation of blue gel pen dyes by ion-pairing high performance liquid chromatography and electrospray tandem mass spectrometry

Ion-pairing high performance liquid chromatography (IP-HPLC) was utilized to monitor the composition changes of blue gel pen ink entries on paper stored in different light conditions and natural environment. The chromatographic conditions were optimized by comparing the separation efficiencies of the blue gel pen inks using a series of ion-pairing reagents, including ammonium carbonate, ammonium acetate, triethylamine acetate, tributylamine acetate, tetrabutylammonium bromide and dihexylammonium acetate. It has been found that tributylamine acetate was a suitable ion-pairing reagent for separation of the inks on the common C18 column. The analysis results of the ink entries on paper in different aging conditions showed that the tendency of composition change in natural aging condition was similar with those in fluorescent light and UV light conditions, respectively. One main component dye of the blue gel pen ink, Acid Blue 9, and its degradation products were identified by ion-pairing high performance liquid chromatography coupled with electrospray tandem mass spectrometry. The results showed that the main degradation products originated from the Acid Blue 9. It gave a reasonable explanation for the changing rules of the relative content of the dyes in the blue gel pen ink. The results obtained can provide scientific evidences for dating of the blue gel pen ink entries on documents.     

Evaluation of the Antioxidant Activity of Nigella sativa L. and Allium ursinum Extracts in a Cellular Model of Doxorubicin-Induced Cardiotoxicity

Natural products black cumin—Nigella sativa (N. sativa) and wild garlic—Allium ursinum (AU) are known for their potential role in reducing cardiovascular risk factors, including antracycline chemotherapy. Therefore, this study investigates the effect of N. sativa and AU water and methanolic extracts in a cellular model of doxorubicin (doxo)-induced cardiotoxicity. The extracts were characterized using Ultraviolet-visible (UV-VIS) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, Liquid Chromatography coupled with Mass Spectrometry (LC-MS) and Gas Chromatography coupled with Mass Spectrometry (GC-MS) techniques. Antioxidant activity was evaluated on H9c2 cells. Cytosolic and mitochondrial reactive oxygen species (ROS) release was evaluated using 2′,7′-dichlorofluorescin-diacetate (DHCF-DA) and mitochondria-targeted superoxide indicator (MitoSOX red), respectively. Mitochondrial membrane depolarization was evaluated by flow cytometry. LC-MS analysis identified 12 and 10 phenolic compounds in NSS and AU extracts, respectively, with flavonols as predominant compounds. FT-IR analysis identified the presence of carbohydrates, amino acids and lipids in both plants. GC-MS identified the sulfur compounds in the AU water extract. N. sativa seeds (NSS) methanolic extract had the highest antioxidant activity reducing both intracellular and mitochondrial ROS release. All extracts (excepting AU methanolic extract) preserved H9c2 cells viability. None of the investigated plants affected the mitochondrial membrane depolarization. N. sativa and AU are important sources of bioactive compounds with increased antioxidant activities, requiring different extraction solvents to obtain the pharmacological effects.     

显微共聚焦拉曼光谱结合群分析的黑色直液笔墨迹鉴别研究

黑色直液笔是一种新型书写工具,目前对该种笔墨迹的相关研究较少。为给文件检验工作中墨迹的分析提供新的参考依据,本实验使用显微共聚焦拉曼光谱技术,采集了30支不同品牌、型号的黑色直液笔墨迹光谱数据,进行Savitzky-Golay卷积平滑处理后,依据光谱图的拉曼位移及拉曼谱峰差异对墨迹进行初步分析。设置聚类方法为组间联接,区间距离测量方式为平方欧式距离,对采集的光谱数据进行群分析,将30支黑色直液笔墨迹样本分成了3类,并与品牌建立了相关联系;同时通过主成分分析验证了群分析的可靠性和准确性。研究表明,显微共聚焦拉曼光谱技术结合群分析方法可实现对黑色直液笔墨迹的无损分析及有效鉴别,该方法操作简便、结果准确,适用于法庭科学文件检验。     

Extracted apocarotenoids from saffron stigmas and evaluated the quality of saffron

Saffron is a kind of expensive spice and therapeutic agent. In order to establish a set of methods to evaluate the quality of saffron, High Performance Liquid Chromatography/Mass Spectrometry (HPLC/MS) were used to identify the apocarotenoids extracted from saffron stigmas. TOPSIS method was applied to evaluate the qualities of saffron. The conditions of HPLC/MS and chemical fingerprints of saffron had been established. The 14 chromatographic peaks and 13 main apocarotenoids of saffron with high reproducibility, stability and specificity were confirmed. The qualities of 40 kinds of saffron from different countries and regions were ranked.     

Bis(merocyanine) Homo-Folda-Dimers: Evaluation of Electronic and Spectral Changes in Well-Defined Dye Aggregate Geometries

A series of three bis(merocyanine) dyes comprising chromophores of different conjugation lengths has been synthesized and the intramolecular aggregation process was investigated by UV/Vis absorption spectroscopy. The spectral changes observed upon variation of the solvent polarity reveal a folding process resulting in a cofacial π-stack of two chromophores with a decrease of the aggregation tendency with increasing chromophore length and solvent polarity. Solvent-dependent UV/Vis studies of the monomeric reference dyes show a significant increase of the polyene-like character for dyes with longer polymethine chains in nonpolar solvents, which is reversed upon aggregation due to the polarizability effect of the adjacent chromophore within the dye stack. The pronounced hypsochromic shift of the absorption band observed upon aggregation indicates strong coupling of the dyes’ transition dipole moments, which was confirmed by quantum-chemical analysis.     

Determination of secondary metabolites including curcumin in Rheum ribes L. and surveying of its antioxidant and anticancer activity

Dry stem and root of Rheum ribes are used for the treatment of different diseases. In this study, the organic components in the root of R. ribes were extracted by three extraction methods (soxhlet, ultrasonic and maceration) and the efficiencies of these methods were calculated. To validate the existence of Curcumin, analysis such as UV–Vis (Ultraviolet–Visible), HPLC (High Performance Liquid Chromatography), GC (Gas Chromatography) and GC/Mass were performed and in order to separate Curcuminoids, TLC (Thin Layer Chromatography) technique was implemented on the extract which had the highest yield. Total phenolic, flavonoid and flavonol contents of three kinds of extract were measured. For studying antioxidant activity, DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging was done. Finally, for investigating anticancer activity, MTT (Methyl Thiazolyl Tetrazolium), NBT (Nitro Blue Tetrazolium) and DNA-Binding tests were done. The most yield was belonged to soxhlet extract. The results showed the presence of Curcumin in soxhlet extract has not been reported previously. Furthermore, the total phenolic, flavonoid and flavonol contents were belonged to ultrasonic extract. As well as the maximum antioxidants properties were belonged to ultrasonic and maceration extraction. The MTT assay showed the lowest IC₅₀ in the ultrasonic extract. At NBT test, the highest NBT reduction percentage was belonged to maceration extraction. DNA-binding test revealed that all the extracts have shown some degree of fragmentation. Due to the presence of Curcumin in R. ribes and the notable features that the results showed, it can be a good source for Curcumin extraction and use in the drug industry.     

TOF-SIMS and FT-IR investigations of surface modified silicon wafers — porous silicon

Surface modification of silicon wafers by anodic etching in hydrofluoric acid results in the formation of porous silicon layers consisting of nanocrystallites covered with SiH bonds. A combination of high resolution Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and Fourier Transform Infrared Spectroscopy (FT-IR) was used to study the surface chemistry of this new material.     

Studies on inclusion complexes of 2,4-dinitrophenol, 2,4-dinitroaniline, 2,6-dinitroaniline and 2,4-dinitrobenzoic acid incorporated with β-cyclodextrin used for a novel UV absorber for ballpoint pen ink

The inclusion complexes of β-cyclodextrin with different dinitrocompounds like 2,4-dinitrophenol, 2,4-dinitroaniline, 2,6-dinitroaniline and 2,4-dinitrobenzoic acid appears the UV absorption bands in different wavelength region below 400 nm, a combination of these dinitro aromatic compounds of inclusion complexes can improve the UV protection properties of ball point pen ink against photo degradation. The formation of inclusion complexes were characterized by FT-IR, ¹H NMR and 2D ROESY NMR spectroscopy. The UV protecting properties of these inclusion complexes were calculated their sun protection factor was discussed. The stability of the ballpoint pen ink has been confirmed by UV–visible spectroscopic method.     

Study and characterization of mural paintings from XIX Century in a noble Venetian (Italy) palace

The present paper describes the characterization carried out on the roof of a private palace located in the historical center of Venice (Italy). We focused our attention on the studies of original constituent materials (pigments and binders), in order to identify the pictorial technique of the artist and verify the stylistic attribution to Giuseppe Borsato, a Venetian painter operating between 18th and 19th century. Characterization of collected samples was carried on using both conventional and advanced analytical techniques, such as Optical Microscopy and Scanning Electron Microscopy coupled with Energy Dispersive X-Ray (SEM–EDS) microscopy, Fourier Transform Infrared Spectroscopy (FTIR) and High Performance Liquid Chromatography (HPLC) coupled with photodiode array detection (DAD) and Mass Spectrometry (MS). The finding of dating pigments (such as Cobalt blue and Cu–As based green) and of a complex binding's mixture compatible with the considered supposed period, allowed us to confirm the attribution hypothesis.     

Biodegradation of poly (vinylalcohol) with enzymatic extracts of phanerochaete chrysosporium

Commercial poly(vinylalcohol) samples (PVOH) of average molecular mass (Mw) 120,000 g/mol, were subjected to biodegradation with enzymatic extracts of the Phanerochaete chrysosporium fungus, in which the lignine peroxidase activity (LiP) was detected. The results of differential refractive index and ultraviolet (UV) absorption Gel Permeation Chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography coupled to a Mass Detector (GC-MS) allow to deduce that in 15 days, under the conditions of this study, the average molar mass of the polymer decreases in 79.3 %. The benzaldehyde was detected as the main degradation product.