Instrumental Analysis Techniques Research Articles

Comprehensive chemical comparison of fuel composition and aerosol particles emitted from a ship diesel engine by gas chromatography atmospheric pressure chemical ionisation ultra-high resolution mass spectrometry with improved data processing routines.

The analysis of petrochemical materials and particulate matter originating from combustion sources remains a challenging task for instrumental analytical techniques. A detailed chemical characterisation is essential for addressing health and environmental effects. Sophisticated instrumentation, such as mass spectrometry coupled with chromatographic separation, is capable of a comprehensive characterisation, but needs advanced data processing methods. In this study, we present an improved data processing routine for the mass chromatogram obtained from gas chromatography hyphenated to atmospheric pressure chemical ionisation and ultra high resolution mass spectrometry. The focus of the investigation was the primary combustion aerosol samples, i.e. particulate matter extracts, as well as the corresponding fossil fuels fed to the engine. We demonstrate that utilisation of the entire transient and chromatographic information results in advantages including minimisation of ionisation artefacts and a reliable peak assignment. A comprehensive comparison of the aerosol and the feed fuel was performed by applying intensity weighted average values, compound class distribution and principle component analysis. Certain differences between the aerosol generated with the two feed fuels, diesel fuel and heavy fuel oil, as well as between the aerosol and the feed were revealed. For the aerosol from heavy fuel oil, oxidised species from the CHN and CHS class precursors of the feed were predominant, whereas the CHOx class is predominant in the combustion aerosol from light fuel oil. Furthermore, the complexity of the aerosol increases significantly compared to the feed and incorporating a higher chemical space. Coupling of atmospheric pressure chemical ionisation to gas chromatography was found to be a useful additional approach for characterisation of a combustion aerosol, especially with an automated utilisation of the information from the ultra-high resolution mass spectrometer and the chromatographic separation.

Characterization and identification of luminescent components in inks using various analytical techniques for the study of crossed-line intersections

Several analytical instrumental techniques have been tested and utilized in an effort to determine the sequencing in crossed-line intersections (CLI) in order to gain insight into the eventual development of a standardized method to determine temporal sequence of line writing. One important facet of this study was to determine the chemical identity of the luminescent compounds present in the formulation of inks to better understand the interaction of different inks in crossed-line intersections. This study involved independent analyses of a number of inks by three laboratories. A combination of Thin Layer Chromatography (TLC), Gas Chromatography Mass Spectrometry (GC/MS), High Performance Liquid Chromatography (HPLC), Matrix-Assisted Laser Desorption Mass Spectrometry (MALDI-MS), Direct Analysis in Real Time Mass Spectrometry (DART-MS), and Liquid Chromatography Mass Spectrometry (LC-MS) were implemented by the three laboratories in order to characterize the luminescent components of inks present in crossed-line intersections. A combination of luminescent compounds including Crystal Violet and Methyl Violet were characterized and identified to be present in mixtures in the ink formulations utilizing each of the analytical techniques included in this study. However, the temporal sequence of deposition of inks present in crossed-line intersections could not be determined. The protocol described here allows for the isolation and characterization of luminescent compounds present in the formulation of inks to varying degrees, and the information presented here can be used in the future establishment of a standard protocol for the identification of luminescent compounds in inks.

Recent Advances in the Chemical, Manufacturing and Regulatory Aspects of Phytopharmaceuticals

Phytopharmaceuticals are now a part of the alternative therapeutic systems. In the earlier days, the scientific community had certain reservations on using the non-standardized medicinal plant products. With the advent of the era of sophisticated instrumentation in chromatography and spectroscopy, research has also focused on the phytopharmaceuticals. The hyphenated techniques such as LC-MS, GC-MS, HPTLC-MS etc have better accuracy, reproducibility and sensitivity. Hence, such techniques are used to identify and quantify the chemical constituents of the phytopharmaceuticals. St. John’s Wort, Milk thistle and Ginkgo represent one of the successful phytopharmaceuticals. There are hundreds of medicinal plants which are yet to be explored for phytopharmaceuticals. The bioactives are being identified using the analytical instrumentation techniques. There have also been talks about the concept of synergy amongst the medicinal plant components. In many cases, it has been reported that the isolated chemical constituents are devoid of the pharmacological effects which were previously seen in the extracts or combination of medicinal plant products. Pharmaceutical industry is one of the largest consumers of the phytopharmaceuticals and it is trying to increase the yield of bioactives in the medicinal plants – often by biotechnological intervention. Of late, the regulatory authorities have started recognizing the phytopharmaceuticals as a separate class. It is hoped that in the coming days, the pharmaceutical technology and nano-technology will be able to contribute productively in the area of phytopharmaceuticals. The present paper is aimed at giving an overview of the chemistry, manufacturing and regulatory aspects of phytopharmaceuticals.

Analytical Strategies Involved in the Detailed Componential Characterization of Biooil Produced from Lignocellulosic Biomass.

Elucidation of chemical composition of biooil is essentially important to evaluate the process of lignocellulosic biomass (LCBM) conversion and its upgrading and suggest proper value-added utilization like producing fuel and feedstock for fine chemicals. Although the main components of LCBM are cellulose, hemicelluloses, and lignin, the chemicals derived from LCBM differ significantly due to the various feedstock and methods used for the decomposition. Biooil, produced from pyrolysis of LCBM, contains hundreds of organic chemicals with various classes. This review covers the methodologies used for the componential analysis of biooil, including pretreatments and instrumental analysis techniques. The use of chromatographic and spectrometric methods was highlighted, covering the conventional techniques such as gas chromatography, high performance liquid chromatography, Fourier transform infrared spectroscopy, nuclear magnetic resonance, and mass spectrometry. The combination of preseparation methods and instrumental technologies is a robust pathway for the detailed componential characterization of biooil. The organic species in biooils can be classified into alkanes, alkenes, alkynes, benzene-ring containing hydrocarbons, ethers, alcohols, phenols, aldehydes, ketones, esters, carboxylic acids, and other heteroatomic organic compounds. The recent development of high resolution mass spectrometry and multidimensional hyphenated chromatographic and spectrometric techniques has considerably elucidated the composition of biooils.

Synthesis and characterization of Ni NPs-doped silica–titania nanocomposites: structural, optical and photocatalytic properties

The synthesis of Ni-doped silica–titania nanocomposite is performed by sol–gel method. The samples prior and after heat treatment at 300 °C for 1 h are characterized by analytical instrumental techniques. FE-SEM and AFM results indicate the regular morphology with low surface roughness without any cracks. EDX analysis verifies the formation of nanocomposites. XRD of the films reveals crystalline titania phases after annealing at 300 °C. The FTIR confirms the bond linkage between silica, titania and nickel molecules. High surface area ~155 m2/g, pore volume of 0.2 cm3/g and pore diameter of 48.10 A are obtained after heat treatment. The magnetic results show that the composite content is reminiscent of ferromagnetic hysteresis loop, with remanence magnetization Mr of 45.35 and 13.20 emu/g for both samples. The organic dye phenol red is used for the evaluation of photocatalytic activity of the synthesized magnetic material. The homogeneous surface morphology, crystalline nature, good solubility of magnetic nanoparticles into the silica–titania matrix show that the Ni/SiO2–TiO2 magnetic photocatalyst can be efficient and reusable.

Emerging Brominated Flame Retardants in Sediments and Soils: a Review

Brominated flame retardants (BFRs) are an important class of commercial chemicals used in a wide variety of products. Several established BFRs are being phased out and replaced with new compounds that are often also brominated. These compounds are so-called emerging BFRs. Very little is known about these emerging BFRs. The analysis of these emerging compounds in environmental samples can provide valuable insight into their environmental behavior. This review summarizes the studies reporting the analysis of emerging BFRs in sediment and soil samples from 2012 to 2015. A list of the different emerging BFRs detected in sediment and soil samples along with their structure is shown. In addition, the different extraction methods used for sediments and soil samples, the various clean-up methods of the sample extracts, and the instrumental analytical techniques are presented.

Emerging latent fingerprint technologies: a review

Emerging latent fingerprint technologies: a review Gurvinder Singh Bumbrah, Rakesh Mohan Sharma, Om Prakash Jasuja Department of Forensic Science, Punjabi University, Patiala, Punjab, India Abstract: Information regarding state of the art technology is accessible by searching in a systematic manner, and is the preferred way of keeping up to date. In this review, we present the recent developments in the field of latent fingerprint detection. Recent developments in processing methods including optical, physical, and chemical methods, and sophistical instrumental analytical techniques are presented. Keywords: latent fingermarks, cyanoacrylate fuming, ninhydrin, small-particle reagent, gas chromatography-mass spectrometry, matrix-assisted laser desorption ionization

Preparation of potato starch microfibers obtained by electro wet spinning

Starch is one of the most abundant biopolymer in nature. It has been primarily used as a thickener in the food industry. Starch is found in greater amounts in the potato tubers, which is one of the largest food productions in the region of Boyacá-Colombia. Thus, potatoes are a viable source of starch. The main objective of this study is the preparation and characterization of native starch's microfiber by electro wet-spinning technique. The parameters that were changed for each treatment were as follows: the amount of potential applied to the solution, the distance between the needle and the collector and the rate of injection of the solution in order to determine the physical and chemical properties of the membranes, conformed by potatoes starch microfiber. Diverse instrumental analysis techniques were applied. They were: Scanning Electron Microscopy (SEM) to determine the morphologies and diameters of microfibers, Fourier Transform Infrared Spectroscopy (FTIR) to determine the chemical changes, Thermogravimetric Analysis (TGA) and Differential Calorimetry Scanning (DSC) to obtain the thermal transitions and the temperatures of useful. The microfibers were analysed in order to determine their structural properties and thus define the range of application. In conclusion, potatoes starch microfibers were obtained with average diameters of 15, 17, 23 and 25 micrometres, besides the fibers presented a degradation temperature of 304 °C, indicating that fibers are available with diameters of small scale, with good thermal properties. This study will enable the implementation of the microfibers to obtain bio packaging for food products and other applications.

Water Quality Assessment of Aflaj in the Mountains of Oman

<p class="1Body">The research was conducted to assess the <em>aflaj</em> water quality in Al Jabal Al Akhdar, Oman. 9 <em>aflaj</em> were sampled during summer and winter seasons in 2012-2013 to evaluate for the physico-chemical characteristics of major quality parameters; and assess the suitability of <em>aflaj</em> for irrigation purposes. Samples collection, handling and processing followed the standard methods recommended by the <em><em>American Public Health Association </em></em><em>and </em>analysed in quality assured laboratories using appropriate analytical methods and instrumental techniques. The quality parameters of the selected <em>aflaj</em> water indicated their suitability for irrigation as most of the quality parameters were within the permissible limits set by Omani regulations of wastewater reuse for irrigation. These selected water resources are excellent or good in quality for irrigation purposes based on the evaluation of different hazards parameters including the salinity-alkalinity hazards which indicate good to admissible water based on electrical conductivity and sodium adsorption classification; and water quality indices which reveal high or moderate classes, indicating the suitability of <em>aflaj</em> for irrigation of the majority of crops and soils. This study is a first comprehensive assessment towards providing indicators and classification indices on irrigation water quality of this fragile mountain ecosystem, which will be the basis for future planning decisions on agricultural demand management measures to protect these principal resources for agricultural production in Al Jabal Al Akhdar.</p>

ASSESSMENT OF PESTICIDES IN ENVIRONMENTAL SAMPLES USING VOLTAMMETRIC MOLECULAR IMPRINTED BASED SENSORS: A REVIEW (2006-2015)

The increased concerns about toxic effects of pesticides exposure led to necessity of its monitoring using rapid, sensitive and selective analytical tools. Traditional instrumental analytical techniques are often time consuming, labor intensive and need tedious prior separation or purification steps and expensive instrumentation. Besides those electrochemical sensors can overcome disadvantages of the traditional techniques, MIP-based sensors offer high degree of selectivity in binding target analytes in the presence of their interferents making them ideal for determination of pesticides in complex environmental samples. The scope of this review is to provide a general overview on MIPs field discussing first methods of MIP preparation and then dealing with applications of MIP based sensors in assessment of pesticides in environmental samples using voltammetry as transduction mechanism.

Pengaruh Penerapan ISO 9001:2008 Terhadap Kepuasan Pelanggan (Pasien) Pada Balai Pengobatan PT. Kertas Leces (Persero) di Probolinggo

Global challenges can not be avoided either from government or private sector, like it or not all parties are required to prepare themselves to be able to survive the standardization of management has become a major issue, more specifically the standardization of quality management systems (ISO 9001:2008). To that end, the government and private agencies need to set up the framework of the system towards a desired quality of the institution in accordance with the goals and objectives. Through human resources, infrastructure and working environment of the application of ISO 9001:2008 in the sense that the goal or objective quality of an institution capable of achieving conformity with the wishes of the expected (customer satisfaction) or a partner institution. Analyizing the effect of the Implementation of ISO 9001:2008 (human resources, infrastructure and work environment) to customer/patient satisfaction simultaneously or partially at the Medical Center PT. Kertas Leces (Persero). Descriptive and inferential analytic study with purposive sampling 50 respondents questionnaire instrument, Likert scale and multyple regression analysis techniques with a (0.05). Implementation of ISO 9001:2008 (human resources, infrastructure and work environment) with the F test, sig (0.000) Ftable (2.8068) simultaneously is very significant effect to Customer satisfaction with simultaneously determination contribution (85,8%). Variables: Human resources sig (0.000) < a (0.05) and tcount (5.728) > ttable (1.679) partially was very significant with (0.719) partially effect to customer satisfaction, Infrastructure with sig (0.128) > a (0.05) and tcount (1.549) < ttable (1.679) partially was not significant, and the working environments with sig (0.03) < a (0.05) and tcount (3.082) > ttable (1.679) partially was significantly affected by the partial contribution (0.494) to customer satisfaction. Thus showing the good human resources, infrastructure and work environment, the higher level of customer satisfaction. Keywords: Implementation ISO 9001:2008, Human Resources, Infrastructure, Work Environment, and Customer/patient Satisfaction.

Comparison Between the Kinetics of Conventional Maceration and A Cyclic Pressurization Extraction Process for the Production of Lemon Liqueur Using A Numerical Model

AbstractThe purpose of this study was to compare two extraction processes for the production of lemon liqueur (limoncello)—the traditional maceration of lemon peels and a cyclically pressurized extraction process also known as rapid solid‐liquid dynamic extraction (RSLDE) that uses a Naviglio extractor. To evaluate the extraction efficiency of the two processes, dry matter obtained by the evaporation of the extracts was used to construct kinetics curves. The dry matter was directly proportional to the amount of the active principle (terpenes) extracted and consequently to the total concentration. Alcoholic extracts were analysed by gas chromatography (GC) to monitor the extraction kinetics for major components of the terpene fraction and for minor components of essential oils. Moreover, alcoholic extracts were analysed by UV spectrophotometry to identify the more abundant chemical species, while the organoleptic tests (i.e., a consumer test) performed on the final product (limoncello) provided an indication of the taste of the final product and revealed features undetectable with instrumental analytical techniques. To better understand the phenomenon considered, a numerical simulation was performed to evaluate and compare the matter flow of extractable compounds during the process.Practical ApplicationsThe mathematical model shown in this work is a scientific novelty because it is not reported in the previous literature. Indeed, the curves obtained from the kinetic analysis of the two solid‐liquid extraction procedures were interpolated to obtain a numerical model, which regulated the two extraction processes. Comparison between the kinetics of the extraction procedures showed that the rapid solid‐liquid dynamic extraction (RSLDE) process was 120 times faster than maceration and had a greater efficiency in a short time. Finally, a method proposed to follow the kinetics of the dilution of alcohol by water contained in the peels using the Karl Fisher titration method was important for establishing the alcoholic content of the beverage.

Separação e identificação de aditivos em tinta por TLC-IR/ UATR e extração seletiva

Resumo Vários aditivos são incorporados nas formulações de tintas para evitar defeitos no revestimento e melhorar o desempenho nas aplicações, constituindo, desse modo, um sistema complexo. A caracterização de uma composição pode ser realizada por separações física/ química e técnicas analíticas instrumentais. A análise de multicomponentes é utilizada no estudo de não conformidades, investigação forense e pesquisa e desenvolvimento de novos produtos. As pesquisas correlatas, em geral, utilizam metodologias convencionais, encontrando algumas limitações, o que motiva a utilização de técnicas alternativas, incluindo acoplamentos, para a análise de aditivos em tintas. Nesse contexto, foi avaliada a aplicabilidade do acoplamento (indireto ou off-line) das técnicas de cromatografia de camada fina (TLC) e espectroscopia no infravermelho com transformada de Fourier (FT-IR), denominado TLC-IR, e extração seletiva na análise de aditivos em tinta à base de resina poliuretânica (PU) e nitrocelulose (NC). Foi utilizada uma formulação, avaliados três sistemas de eluentes e um tipo de revelador, o de Gibbs. Os espectros FT-IR foram obtidos por Reflexão Total Atenuada Universal (UATR). Os principais resultados mostraram que o plastificante Acetil Tributil Citrato (ATBC), aditivo majoritário, foi facilmente identificado por TLC-IR. A metodologia permitiu detectar e diferenciar plastificantes do tipo ftalato, como dioctil ftalato (DOP) e dibutil ftalato (DBP), mesmo em pequena quantidade de amostra, e identificar a oleamida (aditivo promotor de deslize) por meio de extração seletiva e UATR.

Simple Instrumental and Visual Tests for Nonlaboratory Environmental Control.

Proposed are simple and available techniques that can be used for rapid and reliable environmental control specifically of natural water by means of instrumental and visual tests in outdoor conditions. Developed are the chemical colorimetric modes for fast detection of socially dangerous trace impurities in water such as Co(II), Pd(II), and Rh(III) as well as NO2 −-ions and Fe(III) serving as model impurities. Application of portable digital devices and scanner allows estimating the color coordinates and increasing the accuracy and sensitivity of the tests. The combination of complex formation with preconcentration of colored complexes replaces the sensitive but time-consuming and capricious kinetic method that is usually used for this purpose at the more convenient and reliable colorimetric method. As the test tools, the following ones are worked out: polyurethane foam tablets with sorbed colored complexes, the two-layer paper sandwich packaged in slide adapter and saturated by reagents, and polyethylene terephthalate blister with dried reagents. Fast analysis of polyurethane foam tablets is realized using a pocket digital RGB-colorimeter or portable photometer. Express analysis of two-layer paper sandwich or polyethylene terephthalate blister is realized by visual and instrumental tests. The metrological characteristics of the developed visual and instrumental express analysis techniques are estimated.

Correlation between structural and optical properties of surfactant assisted sol–gel based mesoporous SiO2–TiO2 hybrid nanoparticles for pH sensing/optochemical sensor

The correlation between structural and optical properties of surfactant-assisted hybrid thin films deposited by sol–gel method has been studied. The samples prior and after heat treatment were characterized by analytical instrumental techniques like field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), X-ray diffraction (XRD), transmission electron microscope (TEM) and UV–vis spectroscopy. Microscopic results indicate that the inorganic nanoparticles are much smaller in the presence of surfactant than in the pure hybrid film, and the shape of the inorganic particles and compatibility with surfactant vary at a low-temperature of 100°C. FE-SEM study confirms grain size within 12–20nm range that exhibit regular morphology with large pores without any cracks. EDX analysis verify stoichiometric formation of nanocomposite. XRD of the films reveal amorphous to crystalline anatase titania phase after annealing at low-temperature of 100°C. The FTIR confirms the bond linkage between silica, titania and surfactant molecules. The refractive index of 1.48, with thickness 138nm and porosity 73% of the films are measured with spectroscopic ellipsometry. Band-gap of 3.8eV is obtained from the absorption of UV–vis spectroscopy. UV–vis spectroscopy reveals that the prepared matrix shows good response at pH 12 with 96.19% repeatability without leaching and has potential as optochemical sensor with fast response time.

Assessment of Total Suspended Particulates (TSP) in Ikot Abasi L. G. A., Nigeria

Concentrations of major, minor and trace elements in the total suspended particulate (TSP) matter around Ikot Abasi were determined by instrumental nuclear activation analysis (INAA) technique using the thermal neutrons from the first Nigerian nuclear research reactor (NIRR-1) at centre for energy research and training (CERT), Ahmadu Bello University, Zaria. Total suspended particulate (TSP) concentrations ranged between 139±22 µgm-3 and 23±07 µgm-3. The total TSP concentrations from different source groups revealed the commercial sector as the highest contributor of TSP level to the area with a value of 254.64 µgm-3. This value is slightly higher than the µgm-3 standard set by the federal environmental protection agency FEPA. The INAA of the TSP samples show the presence of Al, Na and Mn. Their contributions range between 19.8±3.7 – 119.1±10.1 ppm for Al; 57.4±10.2 - 184±16 ppm for Na and 1.2±0.3 – 4.7±0.4 ppm for Mn in the TSP samples around the study area.

Mesoporous SiO2–TiO2 nanocomposite for pH sensing

Thermally stable mesoporous silica–titania nanocomposite matrix was obtained via sol–gel method. The samples prior and after heat treatment were characterized by analytical instrumental techniques like Field Emission Scanning Electron Microscope (FE-SEM), Energy Dispersive X-ray Spectroscopy (EDX), Atomic Force Microscopy (AFM), X-ray Diffraction (XRD), Thermal Gravimetric Analysis (TGA), surface area, porosity measurements and UV–Vis Spectroscopy. The FE-SEM and AFM micrographs suggest that the indicator molecules are homogeneously diffused into matrix pores of the silica–titania network. The matrix exhibits regular morphology with large pores without any cracks. Energy Dispersive X-ray Spectroscopy (EDX) analysis verified the stoichiometric formation of encapsulated silica–titania nanocomposite matrix whereas calculated average crystallite size 3.82nm was obtained by XRD. N2 adsorption isotherms explain the mesoporous nature of the silica–titania nanocomposite matrix with high surface area value of 401m2/g with a pore size of 3.3nm and pore volume of 0.33cm3/g. UV–vis spectroscopic determinations revealed that the prepared nanomatrix shows good sensitivity between pH range of 3–5 for acidic medium within 6.9s and pH 12 for basic medium within 1.03s; it is indicative that pH sensor is more responsive toward strong basis. It can be deduced that the sensing species are probably better encapsulated in the matrix and show faster response time. The fabricated pH sensor was found to have a six months age stability and high reproducibility in terms of absorption and color stability with response time. A reversible response over a range of pH values between 3 and 12 were obtained. The encapsulated pH indicator silica–titania nanocomposite matrix after 2h heating at 150°C shows a great potential to be used as pH sensor with good material stability, reproducibility/repeatability, reversibility, fast response and long life time behavior.

Recycling flue gas desulphurization (FGD) gypsum for removal of Pb(II) and Cd(II) from wastewater

The present study aims to verify the feasibility of directly reusing the flue gas desulphurization (FGD) gypsum generated from coal-fired power plants to adsorptively remove Pb(II) and Cd(II) from wastewater. The Toxicity Characteristic Leaching Procedure (TCLP) test was conducted to evaluate the leachability of toxic heavy metals from FGD gypsum. The adsorption behaviors of FGD gypsum for Pb(II) and Cd(II) such as pH impact, sorption kinetics, sorption isotherms and sorption thermodynamics were studied in a series of batch experiments. The pH studies indicated that the adsorption of Pb(II) and Cd(II) had their best adsorption amounts both at the pH values from 5.0 to 7.0. The kinetic analysis displayed that the adsorption processes both followed the pseudo-second order model well, and the FGD gypsum provided a higher sorption rate for Pb(II). Equilibrium studies showed that the adsorption of Pb(II) and Cd(II) could be properly described by Langmuir isotherms model, and the predicted maximum adsorption capacities were even greater than some specially prepared adsorbents. The thermodynamic investigation confirmed that the removal of Pb(II) and Cd(II) from aqueous medium could carry out spontaneously, and the higher temperature favored the processes. The instrument analysis techniques were also employed to deeply understand the mechanism involved in Pb(II) and Cd(II) removal by FGD gypsum. Overall, good sorption performance together with cost-effective characteristic makes FGD gypsum potentially attractive material for the Pb(II) and Cd(II) removal in industrial wastewater.

Low-cost Spectrometer for Icelandic Chemistry Education

Spectrometers are common analytical instruments in Chemistry. Ultraviolet-visible (UV-Vis) spectroscopy is the most commonly applied instrumental analysis technique being used at universities in the United States for the last three decades. Due to the popularity of spectroscopy and reduced budgets for undergraduate laboratories, there is great interest in low-cost, Do-It-Yourself spectrophotometers. This paper presents an implementation devised with axiomatic design principles for an affordable (sub $1000) spectrometer. This design can be fabricated in a local Fab Lab using common off the shelf components and material to serve as a rigorous, analytical and teaching tool with a lifespan of at least 5 years. Due to a flaw in the concept of the optical path of the device, consistent measurements on absorption spectra could not be made comparable to a commercial equivalent. Even with this limitation, the device is still capable of serving its original purpose by measuring light source spectra and absorption of a selected wavelength to demonstrate Beer's law.

Structural characterization and oxidation study of a Chinese lignite with the aid of ultrasonic extraction

Chinese lignite coal from the Beizao mine which located in Shandong Province of China was studied using a combination of ultrasonic extraction under mild conditions (which generate minimal chemical changes) in conjunction with modern analytical instrumental techniques. This procedure allowed the development of a structural model. Calculations with the Gaussian 09W package generated an optimized structural geometry and also determined the activities of various functional groups. The initial stages of oxidation were found to consist of the oxidation of hydroxyl groups, the rupture of C–O and C–C bonds, and the dehydrogenation of carboxyl groups. In contrast, both the decarboxylation and decarbonylation reactions were determined to require significant energy inputs and thus occur only at high temperatures. In situ Fourier transform infrared analyses were used to confirm the results of the theoretical calculations.