Azospirillum is a gram negative plump AND straight rods bacterium. 4 Tehran forest parks were selected: (Chitgar, Sohanak, Sorkhehhesart, AND Toska) in order to Azospirillum isolation. Two samples are provided from each park, one of them from forested zones AND the other from non forested Zone. NFb (Nitrogen Free malat) semisolid medium AND RC (Rodriquez Caceres) used for culturing. The biochemical tests used for separation species. Azospirillum species were isolated in these soils. Our researches showed three species  A.brasilense, A. lipoferum AND A. irakense. Microbial population is determined by MPN (Most Probably Number) method. In average, the amount of population in forested zones is 4.3×105 AND in non forested zones is 1.43×105 (bacterial cell in each grams of soil (CFU/g)) by solid NFb medium. In average, the population in forested zones is 1.91×105 AND in non forested zones is 0.77×105 by solid RC medium. In average, the population in planet forested zones AND in non forested zones were 0.95×103 AND 0.27×103 by semisolid NFb medium. Then the Nitrogen fixation ability of acquired samples was studied. In this way, by use of Rennin Media AND GAS CHROMATOGRAPHY AND by transformation Acetylene to Etilen the Nitrogenase of sample were determined. Acetylene reduction in A. lipoferum was highest in comparison with other species AND was 86.27 nmol/24hTube AND A. irakense was least in comparison with other species AND was 23.92 nmol/24hTube AND A. brasilense was 56.4 nmol/24hTube.

Static headspace combined with GAS CHROMATOGRAPHY/mass spectrometry is a powerful technique which can be used for separation AND identification of volatile organic compounds in complex AND different matrices such as soil, water, blood, urine, milk, cheese AND especially yogurt. After sample collection, they were analyzed by HS-GC/MS system AND the components (acetaldehyde, acetone, butanone AND acetic acid) were detected AND quantified. The limit of detection (LOD) was 100 ng/kg with selected ion monitoring (SIM) mode at m/z =60 for acetic acid. The relative stANDard deviation (RSD) was measured at 5.5% for acetic acid.

Multidetector systems have been widely used in GC for many years. Even though the mass spectrometer is still the most popular GC detector in the case of complex samples, a multidetector system can provide all the information needed for the confirmation purposes. This review describes various GC setups for multidetector analysis, AND modern systems available on the market. An overview of the application of multidetector systems with various detectors in GC is also enclosed. The most popular system involves parallel detectors AND a post-injector or postcolumn effluent splitter.

In this study, leaming intensity is measured in terms of labor cost savings AND productivity growth through experience, as well as the effects of mergers  AND acquisitions on technology learning using a learning curve AND its effects on the performance of oil, GAS AND products companies. Oil listed on the Tehran Stock Exchange will be evaluated.The novelty of this article is to explain the direct AND indirect effects of M&A (mergers  AND acquisitions) in technology learning that leads to the learning curve model with the M&A factor in the oil, GAS AND petroleum products It can be seen that traditional learning through experience has not reduced costs by increasing cumulative production in refineries AND petrochemical companies. Economies of scale have also failed to reduce operating costs by increasing production at refineries. Learning by research in refining AND petrochemical companies has also reduced operating costs by a year, but is less severe. This study also shows that there is no direct effect of mergers AND acquisitions on technology learning in the combination of refining AND petrochemical companies. In addition, the indirect effects of mergers AND acquisitions on technology learning are seen only in petrochemical companies.

The basic concept of a sample preparation method is to convert a real matrix into a sample in a format that is suitable for analysis. Some GASeous, liquid, AND volatile solid samples are suitable for direct injection to GAS CHROMATOGRAPHY instrument. But most samples are not ready to introduce directly into the column of GC. such as removal of serious interferences from the sample, increase of analyte concentration, convert the analyte into a more suitable form to detect AND determine, using smaller initial sample sizes AND finally achieving higher selectivity. This article discusses various types of analyte extraction, cleanup AND concentration. Extraction methods can include classic techniques such as purge AND trap, static headspace extraction, AND liquid-liquid extraction to newer techniques such as solid phase microextraction, membrane extraction, single drop microextraction AND superheated water extraction.

In this study, two oil samples from Asmari AND Sarvak reservoirs (well No#23) in Pazanan oil field AND one oil sample from Khalij reservoir (well No#1) in Khaviz oil field were subjected to geochemical analyses using GAS CHROMATOGRAPHY (GC) AND GAS CHROMATOGRAPHY Mass-Spectrometry (GC/MS) techniques. Quantitative assessment of the oil components using liquid CHROMATOGRAPHY method revealed that oil samples have a greater amount of saturated hydrocarbon component than the aromatic AND polar. Classification of the crude oil samples based on different components shows that the Asmari AND Sarvak reservoir oil in Pazanan oil field AND Khalij reservoir oil in Khaviz oil field are paraffinic, mainly paraffinic to paraffinic-naphthenic AND paraffinic – naphthenic respectively. The biomarker ratio obtained from C29 Sterane β β ∕ (β β +α α ) versus C29 Sterane 20S/(20S+20R) diagram demonstrates that the oil samples were produced at the maximum stage of the oil producing window AND have relatively high thermal maturity. The DBT/Phen versus Pr/Ph diagram shows that the Asmari oil samples have been produced from carbonate-shale, AND Sarvak AND Khlij oil samples have been produced from carbonate-marl source rocks. Also, triangular C27, C28, C29 sterane diagram indicates that the source rocks have been deposited in open marine to parallic environment. Also, oil has been generated from organic matter with type II kerogen as inferred from Pr/nC17 versus Ph/nC18 diagram. The proximity of the Carbon Preference Index (CPI) to the number 1, indicates high maturity level for source rocks. Absence of oleanane biomarker in oil samples suggests that oils be produced from lower-Cretaceous source rocks. Oil-oil correlation using distinctive biomarkers allowed to plot the stellar graph. Finally, the even/odd ratio of normal alkanes determines that the oil samples from Asmari, Sarvak, AND Khalij reservoirs have been produced from a variety source rocks.

In this paper various factors that effected on separation of mono AND di substituted nitro toluene compounds was investigated by GAS CHROMATOGRAPHY method AND optimum separation condition was reported for 2-nitrotolouen (2NT), 4-nitrotolouen (4NT), 2,3-dinitrotolouen (2,3DNT),  2,4-dinitrotolouen (2,4DNT), 2,6-dinitrotolouen (2,6DNT)  AND 3,4-dinitrotolouen (3,4DNT) compounds. Optimum carrier GAS flow rate AND injection volume was 20-30 ml.min-1 AND 0.3 t1, respectively. Isothermal separation method wasn’t accepted for given good results AND then programming mode (T1=80 OC, t1=6S, scan rate=30, T2=240, t2=6s) was used.

Background AND Aim: Nowadays, drug abuse is a major problem in societies AND, detection of drugs in urine is very important. In general, immunoCHROMATOGRAPHY (ICG) AND thin-layer CHROMATOGRAPHY (TLC) are routine methods for the detection of drugs in urine. These methods are rapid AND economical, but their accuracy rates for detection of drugs at lower concenterations are low (< cut off). Morphine, amphetamine AND methamphetamine, are conventional drugs that are widely used. The purpose of this study was to compare immunoCHROMATOGRAPHY, thin layer CHROMATOGRAPHY (TLC) AND GAS CHROMATOGRAPHY (GC) methods for detection of morphine, amphetamine AND methamphetamine in the spiked healthy human urine samples AND urine of addicted people. We also compared their detection limits with one another. Materials AND Methods: This was an experimental study AND included urine samples obtained from healthy AND addicted people referring to the laboratory of the 7th of Tir marriage counseling center in East Azerbaijan Province, in June 2016. After collection of urine samples, samples obtained from healthy people were spiked with various concentrations of morphine, amphetamine AND methamphetamine. Then, all samples were tested by immunoCHROMATOGRAPHY, TLC AND GC methods for the detection of morphine, amphetamine AND methamphetamine. Results: Results showed that ICG AND TLC methods can not detect lower concentrations (< cut off) of morphine, amphetamine AND methamphetamine. While, GC can easily detect them in urine samples, even in lower concentrations (< cut off) AND has a high detection limit AND accuracy rate. Conclusion: It can be concluded GC method is a powerful AND accurate technique for detection of drugs in urine samples.

Sterols form the largest proportion of the unsaponifiable fraction of lipids. Plant fats AND oils contain phytosterol as naturally occurring constituents. The most common types of phytosterols in plants are cytosterol, compressor AND stigmometol. Different types of yogurt AND especially high-fat types are foods that are likely to contain added phytosterol. In this study, the presence of cholesterol AND four phytosterols in 62 different yogurts in Tabriz city was investigated in order to assess the addition of vegetable oils. For this purpose, after saponification AND liquidliquid extraction of the samples, non-absorbent materials were purified by thin layer CHROMATOGRAPHY. Then, without the derivative step, the compounds were detected by GAS CHROMATOGRAPHY with a flame ionization detector. In the recent study, the saponification process was optimized AND validated. According to the results, the method was estimated as easy, fast AND repeatable, AND had a high efficiency in detecting sterols in our samples. Cholesterol was found as the highest sterolic compound in all samples (65-99%). Among the phytosterols, campesterol was predominated (4. 7%) followed by brassicasterol (2. 08%). According to the guidelines of Institute of StANDards AND Industrial Research of Iran, 46 (74. 2%) yogurt samples were found unacceptable.