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Search Results: 1 - 10 of 4727 matches for " GC-MS "
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Development and Validation of QuEChERS Method for Estimation of Propamocarb Residues in Tomato (Lycopersicon esculentum Mill) and Soil  [PDF]
Sanjay Kumar Sahoo, Raminderjit Singh Battu, Balwinder Singh
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.228120
Abstract: An easy, simple and efficient analytical method was standardized and validated for the estimation of residues of propamocarb in tomato and soil. QuEChERS method included extraction of the sample with ethyl acetate and cleanup by treatment with PSA and graphatised carbon. Final clear extracts of ethyl acetate were concentrated under vacuum to almost dryness and reconstituted into hexane. The residues of propamocarbwere estimated using gas chromatograph-mass spectrometry (GC-MS). Propamocarb presented a distinct peak at retention time of 8.962 min. Consistent recoveries of propamocarb ranging from 87 to 92 percent were observed when samples were spiked at 0.10, 0.50 and 1.00 mg·kg–1 levels. The limit of quantification (LOQ) of this method was determined to be 0.10 mg·kg–1.
Monitoring of Pesticides Residues in Italian Mineral Waters by Solid Phase Extraction and Gas Chromatography Mass Spectrometry  [PDF]
Anna Maria Tarola, Raffaella Preti
Journal of Water Resource and Protection (JWARP) , 2012, DOI: 10.4236/jwarp.2012.410097
Abstract: Twenty-two pesticides and metabolites, selected on the basis of regional priority lists, were surveyed in thirty Italian mineral waters springs for three years by a procedure based on solid phase extraction in combination with gas chromatography coupled with mass spectrometry detection. The procedure proved to be simple, sensitive and reliable, the limits of detection and relative standard deviations were respectively in the range of 0.002 - 0.04 μg/L and 3% - 7%, recoveries ranged from 86% to 105% at the European Union Maximum Acceptable Concentration (MAC). Pesticide residues were detected in just one of the ninety water samples analyzed but no one exceeding the MAC. These results demonstrate the good quality of Italian mineral waters, not forgetting the need of constant revision and update of the priority list of pollutants.
Study of the Reaction Derivatization Glyphosate and Aminomethylphosphonic Acid (AMPA) with N,O-Bis(trimethylsilyl)trifluoroacetamide  [PDF]
T. C. P. G. Catrinck, Maria Clara Santana Aguiar, Amanda Dias, Flaviano Oliveira Silvério, Paulo Henrique Fidêncio, Gevany Paulino de Pinho
American Journal of Analytical Chemistry (AJAC) , 2013, DOI: 10.4236/ajac.2013.411077
Abstract:

This work aimed to study the derivatization unprecedented of glyphosate and AMPA solutions using N,O-bis (trimethylsilyl)trifluoroacetamide (BSTFA) combined with trimethylchlorosilane (TMCS), evaluating the composition of the reaction medium, use of ultrasound, volume of BSTFA:pyridine and pH of the reaction medium. From this study it was inferred that the reaction medium was composed of BSTFA:pyridine in ratio 60:100, respectively, without ultrasonic vibration and pH adjustment that provide optimal conditions for analysis by GC-MS. Furthermore, the methodology used was simple and fast, and that was the most practical method commonly used.

Impact of Pesticides Contamination on Nutritional Values of Marinefishery from Karachi Coast of Arabian Sea  [PDF]
Hina Ahsan, Nasim Karim, Syed Sanwer Ali, Alia B. Munshi, Sohail Shaukat
Food and Nutrition Sciences (FNS) , 2013, DOI: 10.4236/fns.2013.49120
Abstract:

The present study explores the chemical and economic aspects of pesticide contamination of marinefishery in relation to nutritional values Marine Pollution of pesticides poses signify can tricks to the environment and non-target organisms ranging from beneficial marine micro organisms, to insects, seaweeds, fish, and mangroves at Karachi Coast. Fish typically contains good quality nutrition, particularly oily fish has maximum commercial values but contamination of fishery is the major problem caused by pesticides and PCBs pollution resulting in serious health hazards. A number of fish and shell fish samples were analyzed for determination of pesticides contamination due to marine environment pollution. It was found that most pesticides pose risk to humans, fishery or the environment because they are designed to kill or adversely affect living organisms. Quantitative analysis of pesticides and PCBs was performed using GC equipped with ECD and the FPD for organophosphorus and GC-MS. The arithmetic mean concentrations of each pesticide were calculated and statistical evaluation was done. Relationship of protein and pesticides level has been determined to determine impact of pesticide on protein content of each type of fish. There is a considerable difference found in the pesticides contents of each type of fishery, which reveals that environmental pollution status that attributes towards pesticides distribution.

Isolation and identification of an isomer of β-sitosterol by HPLC and GC-MS  [PDF]
Yi Sheng, Xiao-Bin Chen
Health (Health) , 2009, DOI: 10.4236/health.2009.13034
Abstract: Phytosterols are a group of steroids alcohols which had been regarded as a functional factor. An unknown compound in phytosterol samples and phytosterol standard samples was detected by HPLC using symmetry C18 column. The quan- tity of the compound was increased with the enrichment of β-sitosterol. After being collected and analyzed by GC-MS and compared with standard diagram from Wiley and Nist standard chart library, it proved to be γ-sitosterol, a 24β epimer of β-sitosterol.
Active volatiles of cabernet sauvignon wine from Changli County  [PDF]
Yong-Sheng Tao, Hua Li
Health (Health) , 2009, DOI: 10.4236/health.2009.13029
Abstract: This study investigated the contribution of vola-tile compounds to the overall aroma of Cabernet Sauvignon wines from Changli County (China). Wine samples were collected from vintages from 2000 to 2005. Volatile compounds were ex-tracted by PDMS solid-phase micro-extraction fi- bers and identified by Gas Chromatography-Ma- ss Spectrometry (GC-MS). A total of 65 volatile compounds were identified and quantified, in-cluding higher alcohols, ethyl and acetate esters, and fatty acids. According to their odor active values (OA-Vs), 21 volatile compounds were con- sidered to be the powerful impact odorants of Cabernet Sauvignon wines from Changli. Odor descriptions of impact volatiles suggested Cab-ernet Sauvignon red wines from Changli County as having a complex aroma, which included not only pleasant floral and fruity odors, but also cheese, clove flavors, and grassy and smoky aromas.
Determination of Sterane and Triterpane in the Tamsagbulag Oilfield  [PDF]
B. Byambagar, E. Enkhtsetseg, D. Monkhoobor, B. Avid, A. Tuvshinjargal
Advances in Chemical Engineering and Science (ACES) , 2011, DOI: 10.4236/aces.2011.13024
Abstract: Crude oils representing four different holes from the Tamsagbulag oilfield were analyzed by gas chromatography-mass spectrometry (GC/MS) spectroscopy. Fifty-two biomarker compounds, 34 pentacyclic triterpanes and 18 steranes were identified and semi-quantitatively determined by selective ion monitoring (SIM) chromatography. Depending on the oil source, the variation in the pentacyclic triterpanes distribution is more significant than the variation in the sterane distribution. It is said that pregnane and honopregnane originated during the period of very salty sedimentary accumulation in the condition of diagenesis.
PAHs in Sediments along the Semi-Closed Areas of Alexandria, Egypt  [PDF]
Mohamed A. Shreadah, Tarek O Said, Mohamed I. Abd El Monem, Eiman M. I. Fathallah, Mohamed E Mahmoud
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.26081
Abstract: Sediment samples were collected from 49 sampling stations along the semi-closed areas of Alexandria coasts, Egypt. Total concentrations of 15 out of 16 EPA-PAHs in sediments were varied from 4.2 to 886 ng.g–1 with an average value of 176 ng.g–1 (dry wt). The average total organic carbon (TOC) percent was varied from 0.04 to 7.65%. Higher concentration of total pyrolytic hydrocarbons (∑COMB) than total fossil hydrocarbons (∑COMB), declared that atmospheric fall-out is the significant source of PAHs to marine sediments of the semi-closed area of Alexandria. The selected marked compounds and special PAHs compound ratios (phenanthrene/anthracene; fluoranthene/pyrene; ∑COMB/ ∑EPA-PAHs) suggest the pyrogenic origins, especially traffic exhausts, are the dominant sources of PAHs in most locations. Interferences of rather petrogenic and pyrolytic PAH contaminations were noticed in the harbours, especially marine area due to petroleum products deliveries and fuel combustion emissions from the ships staying alongside the quays.
Chemical composition, antioxidant and antibacterial activities of essential oil from Korean Citrus unshiu peel  [PDF]
Xiao Nan Yang, Sun Chul Kang
Journal of Agricultural Chemistry and Environment (JACEN) , 2013, DOI: 10.4236/jacen.2013.23007
Abstract: The chemical composition, antioxidant and antibacterial activities of essential oil from peel of Citrus unshiuwhich cultivated in South Korea were investigated. Eight compounds were identified as l-limonene (88.11%), γ-terpinene (4.66%), cyclohexane, 2,4-diisopropenyl-1-methyl-1-vinyl (1.82%), diethyl phthalate (1.02%), β-linalool (0.97%), β-myrcene (0.91%), α-farnesene (0.91%) and o-cymene (0.85%)
by GC-MS. The SC50values of this essential oil on DPPH and superoxide anion were 0.21 and 0.22% (v/v), respectively. The results of zone of inhibition, MIC, MBC and cell viability demonstrated the essential oil of-Citrus unshiupeel displayed antibacterial effect against B. cereus KCTC 14042, B. subtilis ATCC 6633 and S. aureusATCC 6538. The release of cell material and potassium ion from the B. subtilis ATCC 6633 cells treated with essential oil was further investigated. SEM observation also revealed the damaging effect of the essential oil on the morphology of B. subtilisATCC 6633 cells at minimum inhibitory concentration.


Essential Oil of Grape Fruit (Citrus paradisi) Peels and Its Antimicrobial Activities  [PDF]
Wahab O. Okunowo, Olajumoke Oyedeji, Lukman O. Afolabi, Eniola Matanmi
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.47A2001
Abstract:

Plants and plant products are continuously being explored in medicine against the increasing number of antibiotic resistant organisms. The antimicrobial activity of essential oil of some plants has been demonstrated against a range of organism. This study aimed to determine the chemical constituents and the antimicrobial effects of the oil of grape peels on some clinical isolates. The oil was obtained from the peels by hydrodistillation procedure and analyzed using Gas chromatography coupled to mass spectrometer. The in-vitro antimicrobial property of the methanolic, ethanolic and tween 80 mixture of extract was determined by agar well diffusion method against selected clinical bacterial isolates (Bacillus cereus, Enterococcus faecalis, Escherichia coli, E. coli ATCC 25292, Klebsellia pneumonia, Pseudococcus sp., Salmonella typhmurium, Shigella flexneri, Staphylococcus aureus, Staphylococus aureus ATCC 29213) and fungal isolates (Aspergillus niger, Candida albican, and

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