Tests of Antibiotic Properties of Algerian Desert Truffle against Bacteria and Fungi

In the present paper, the ethyl acetate extract from the fruiting bodies of Tirmania pinoyi （Maire） was obtained by Soxhlet extraction. Six fractions were separated from this extract using two chromatographic methods. All these fractions were submitted to antimicrobial activity against four clinically important bacteria Staphylococcus aureus ATCC6538, Enterococcusfaecalis ATCC6538 Pseudomonas aeruginosa ATCC14028, Escherichia coli ATCC25922 and one pathogenic fungus Candida albicans ATCCI0231. The in vitro antimicrobial activity was performed by agar disc diffusion method. The fractions with the greatest antimicrobial activity were fractions 02 and 06 which inhibited growth of both Gram negative and Gram positive bacteria and had significant antifungal activity against Candida albicans. The present study validates the folk use of the boiled truffle water-extract and indicates that it could be effective potential candidates for the development of new strategies to treat bacterial or fungal infections.

Analysis of Sucrose Esters with Long Acyl Chain by Coupling of HPLC-ELSD with ESI-MS System

The analysis of sucrose esters with long acyl chain by improved high performance liquid chromatographic method with evaporative light scattering detection （HPLC-ELSD） and electrospray ionization mass spectrum （ESI-MS） is investigated. The improved HPLC-ELSD method for the separation and quantitation of commercial and synthesized sucrose esters is described. Samples are analyzed by means of a reversed-phase （RP） HPLC using a Hypersil C8 column （250 mm× 4.6 mm, 5 μm particle size） with methanol-tetrahydrofuran （vo）ume ratio of 90 ： 10） and water under gradientcondition as the mobile phase, in which the flow rate is 1.0 ml·min^-1 and the column temperature is set at 40℃. This procedure provides a complete separation and determination ot monoester, diester, triester and higher esters with different acyl chain lengths in each fraction by a single run, in combination with the ESI-MS technology. With this method, it is possible to determine the approximate compositions of monoto polyesters in one analysis and quantitate pure positional isomers precisely using an external standard method. It is found that the method of ESI-MS coupling with HPLC system for the analysis of sucrose esters is straight forward, rapid and inexpensive, and can be readily applied in synthesis, purification and structure studies.

Fraud investigation in commercial coffee by chromatography

Coffee is currently the second largest commodity on the world market today,and there is great concern about the quality of the beans exported from producer countries to Europe and USA.Practices such as using blends of different species and adding low-cost raw materials,such as chicory,corn,and soybean,impair the sensory and functional characteristics of the drink made from roasted and ground coffee beans.There is a need to adopt more efficient analytical methods than the microscopy technique currently used.The first chromatographic method used to determine fraud was reported in 1958.This method used paper chromatography to differentiate between coffee and chicory based on the free reducing sugars.As of the 1980s,different methods involving high-performance liquid chromatography and gas chromatography were developed in order to demonstrate geographic authenticity,distinction between species,occurrence of adulteration,and the presence of defective beans by determining the monosaccharides,oligosaccharides,tocopherols,fatty acids,volatiles,diterpenes,sterols,and phenolic substances,among others.As far as the authors know,there are no papers published in the literature that have compiled such an extensive set of information about these chromatographic methods as here.Over the last 2 years,there has been a trend to develop analytical methods for ultra-performance liquid chromatography coupled with tandem mass spectrometry to confirm fraud in coffee,due to high sensitivity and selectivity.

Applying a new method for direct collection, volume quantification and determination of N_2 emission from water

The emission of N2 is important to remove excess N from lakes, ponds, and wetlands. To investigate the gas emission from water, Gao et al.（2013） developed a new method using a bubble trap device to collect gas samples from waters. However, the determination accuracy of sampling volume and gas component concentration was still debatable. In this study, the method was optimized for in situ sampling, accurate volume measurement and direct injection to a gas chromatograph for the analysis of N2 and other gases. By the optimized new method, the recovery rate for N2 was 100.28% on average; the mean coefficient of determination（R2） was 0.9997; the limit of detection was 0.02%. We further assessed the effects of the new method, bottle full of water, vs. vacuum bag and vacuum vial methods, on variations of N2 concentration as influenced by sample storage times of 1,2, 3, 5, and 7 days at constant temperature of 15°C, using indices of averaged relative peak area（%） in comparison with the averaged relative peak area of each method at 0 day.The indices of the bottle full of water method were the lowest（99.5%–108.5%） compared to the indices of vacuum bag and vacuum vial methods（119%–217%）. Meanwhile, the gas chromatograph determination of other gas components（O2, CH4, and N2O） was also accurate. The new method was an alternative way to investigate N2 released from various kinds of aquatic ecosystems.