Evaluation of tea tree oil quality and ascaridole: A deep study by means of chiral and multi heart-cuts multidimensional gas chromatography system coupled to mass spectrometry detection

The natural-like assessment of essential oils is a demanding task due to the growing trend toward adulterations. Usually chiral chromatography was used for this purpose due to the capability of assessing stereospecificity which is directly related to the enzymatic pathways of each plant species. On the other hand, the quality of an essential oil involves also the evaluation of its oxidative state, mainly connected with the age and storage conditions. In fact, some modifications in the chemical profile of the oil can occur if not properly preserved. Alterations of the components due to oxidative reactions lead to the formation of peroxides, endoperoxides and epoxides, such as ascaridole and 1,2,4-trihydroxymenthane, usually present in very low amount, formed by the oxidation of terpinen-4-ol and α-terpinene, respectively. Therefore, in the present research, the quality of Australian Tea Tree oil (Melaleuca alternifolia (Maiden & Betche) Cheel, Myrtaceae) was investigated by means of a multi heart-cut multidimensional gas chromatographic system coupled to a mass spectrometer detector and by conventional enantio-GC. The MDGC system allowed the complete separation of the compounds of interest transferred from the first column to a second dimension based on a different separation mechanism. The MS detector at the end of the second column provided the identification of the peaks with high similarity values because of their high purities after the multidimensional separation. Method validation was carried out, in order to use this procedure for routine application, monitoring the repeatability of 1D retention times and 2D peak areas, LoD and LoQ. Finally, enantiomeric ratios for chiral compounds were established to support quality data obtained.     

外星推进剂质量检测标准分析

对比分析了国内外卫星推进剂在取样方法、质量检测方法、检测指标等方面所依据标准的差异,分析了我国推进剂检测实验室依据国际标准对外星推进剂进行质量分析的能力,为推进剂检测实验室具备和提高外星推进剂质量分析的能力提出了具体的措施。     

Isolation and analysis of polycyclic aromatic hydrocarbons from natural water using accelerated solvent extraction followed by gas chromatography-mass spectrometry

An innovative analytical procedure for the analysis of polycyclic aromatic hydrocarbons (PAHs) from large-volume water samples is presented. It involves sample preparation, sampling and the elution process in an automated continuous procedure involving the ASE technique. Prior to sampling, a XAD-2 resin column is prepared on the basis of a commercial accelerated solvent extraction (ASE) cartridge so that the resin bed is permanently fixed. Then, the XAD column inside the ASE cartridge is cleaned and conditioned. The sampling procedure involves conventional filtration with subsequent isolation of dissolved PAHs on an XAD-2 resin contained in the ASE cartridge. After sampling, the XAD-2 resin content inside the cartridge is eluted by ASE without any further sample preparation and subsequently reused. In order to validate the procedure, the PAHs were isolated from water samples from the Lake Maggiore (North of Italy) using both XAD-2 resin adsorption and hexane liquid-liquid extraction according to the International Standard Methodology ISO 17993. The mean percentages of deviation between concentrations obtained by both methodologies range from 6% for benzo(a)pyrene to 15% for fluoranthene and benzo(b,k)fluoranthene. Compared to the traditional techniques, this procedure offers numerous practical advantages: easy to perform, fast, savings in solvent volume and in time, all steps are fully automated thus avoiding any XAD-2 resin manipulation during and between steps and moreover, low detection limits were provided (0.001 ng l⁻¹ for chrysene, benzo(b,k)fluoranthene, benzo(a)pyrene, dibenz(a,h)anthracene, benzo(g,h,i)perylene and indeno(1,2,3-cd)pyrene, and 0.01 ng l⁻¹ for acenaphthylene and fluoranthene).This procedure was developed in the frame of a project aimed at evaluating the diffuse input of organic contaminants in the Lake Maggiore.     

Improving surface‐analysis methods for characterization of advanced materials by development of standards,reference data,and interlaboratory comparisons

This paper summarizes the results of two surveys examining current needs for improved analyses of surfaces. Surfaces and interfaces are increasingly important to science and technologies associated with nanoparticles, nano‐structured materials and other complex materials including those associated with information systems and medical or biological applications. Adequate characterization of advanced materials frequently requires application of more than one analysis method along with the need to analyze data in increasingly sophisticated and sometimes interrelated ways. It is useful for both new and experienced analysts to have ready access to best practices for obtaining accurate and useful information from a variety of different analysis tools. The International Organization for Standardization (ISO) Committee TC 201 on surface chemical analysis and the ASTM Committee E‐42 on surface analysis are working to address these needs by assembling guides and standards reflecting the collective experience and wisdom of experts in this community. Published in 2007 by John Wiley & Sons, Ltd     

Minimum value assured by a method to determine gold in alloys by using laser-induced breakdown spectroscopy and partial least-squares calibration model

A procedure for estimating the minimum value assured by an analytical method has been developed. It is applied to the determination of gold in jewellery alloys by means of a recently proposed spectroscopy technique. The laser-induced breakdown spectroscopic data of 17 gold alloys, with gold concentration ranging between 50 and 100% were used as calibration set for carrying out the partial least-squares regression (PLS). Ninety alloys, with known gold concentration, were used to evaluate the method’s accuracy. Finally, the minimum guaranteed value of the gold content was analysed, taking into account the values for gold hallmark in Spanish regulations.     

Index Calculation Attacks on RSA Signature and Encryption

At Crypto ’85, Desmedt and Odlyzko described a chosen-ciphertext attack against plain RSA encryption. The technique can also be applied to RSA signatures and enables an existential forgery under a chosen-message attack. The potential of this attack remained untapped until a twitch in the technique made it effective against two very popular RSA signature standards, namely iso/iec 9796-1 and iso/iec 9796-2. Following these attacks, iso/iec 9796-1 was withdrawn and ISO/IEC 9796-2 amended. In this paper, we explain in detail Desmedt and Odlyzko’s attack as well as its application to the cryptanalysis of iso/iec 9796-2. AMS Classification: 11T71, 14G50, 94A60     

Self-implementation of ISO 9001 versus external support: an examination in laboratories involved in chemical measurement

The purpose of this research was to study how externalizing the process of implementing ISO 9001 influences the dissemination of cultural values and practices of quality management in laboratories involved in chemical measurement. Employee attitudes and behaviors may be heavily influenced by factors such as the mix of internal workers and consultants in a work group. Some researchers have described cases in which internal workers develop negative work attitudes and behaviors from having to work with consultants and have demonstrated the need to examine the dynamics between internal workers and consultants to understand the influence of ISO 9001 externalization. Three hundred and fifty-nine useful questionnaires were received. The results showed that implementation occurs most successfully through a process of linked internalization. This category involves limiting the labor of the consultant basically to moderate advising, review and internal audit. The laboratory personnel are responsible for developing the documentation of the ISO 9001 system. The implementation process is run by the members and directors of the laboratory.     

Experience of implementing ISO 17025 for the accreditation of a university testing laboratory

The experience of implementing a quality system on ISO 17025, and the accreditation of some tests for a university laboratory, is presented in the example of the Environmental Radiology Laboratory. Such implementation in a university institution is a difficult task, since the setting and environment are both unfavourable. The particularities are the collaboration of many independent units of the university, and the involvement of teachers and young researchers who have to coordinate all these different tasks, which makes the number of people working quite variable. Some specific aspects of the system are discussed. The conclusion is that implementation of a quality system on ISO 17025 and accreditation are completely achievable, and are helpful activities to put university members in touch with the real world and broaden their minds, which in the end has a positive impact on research studies and academic content.     

Field measurement of airborne sound insulation between rooms with non-diffuse sound fields at low frequencies

Procedures for the field measurement of airborne sound insulation between rooms with diffuse fields are described in International Standard ISO 140-4. However, many dwellings contain rooms with volumes less than 50 m³, where low frequency measurements are less reliable; hence there is a need for a measurement procedure to improve the reliability of field measurements in rooms with non-diffuse fields. Procedures are proposed for sound pressure level and reverberation time measurements for the 50, 63 and 80 Hz third octave bands. The sound pressure level measurement combines corner microphone positions with positions in the central region of each room. This provides a good estimate of the room average sound pressure level with significantly improved repeatability.