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Fulltext Determination of polycyclic aromatic hydrocarbons in fresh milk by hollow fiber liquid-phase microextraction-gas chromatography mass spectrometry

Sanagi MM, Loh SH, Wan Ibrahim WA, Hasan MN, Aboul Enein HY

J Chromatogr Sci, 2013 Feb;51(2):112-6.
PMID: 22776739 DOI: 10.1093/chromsci/bms113

In this work, a two-phase hollow fiber liquid-phase microextraction (HF-LPME) method combined with gas chromatography-mass spectrometry (GC-MS) is developed to provide a rapid, selective and sensitive analytical method to determine polycyclic aromatic hydrocarbons (PAHs) in fresh milk. The standard addition method is used to construct calibration curves and to determine the residue levels for the target analytes, fluorene, phenanthrene, fluoranthene, pyrene and benzo[a]pyrene, thus eliminating sample pre-treatment steps such as pH adjustment. The HF-LPME method shows dynamic linearity from 5 to 500 µg/L for all target analytes with R(2) ranging from 0.9978 to 0.9999. Under optimized conditions, the established detection limits range from 0.07 to 1.4 µg/L based on a signal-to-noise ratio of 3:1. Average relative recoveries for the determination of PAHs studied at 100 µg/L spiking levels are in the range of 85 to 110%. The relative recoveries are slightly higher than those obtained by conventional solvent extraction, which requires saponification steps for fluorene and phenanthrene, which are more volatile and heat sensitive. The HF-LPME method proves to be simple and rapid, and requires minimal amounts of organic solvent that supports green analysis.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods*
Fulltext Separation and identification of volatile compounds from liquid cultures of Trichoderma harzianum by GC-MS using three different capillary columns

Siddiquee S, Cheong BE, Taslima K, Kausar H, Hasan MM

J Chromatogr Sci, 2012 Apr;50(4):358-67.
PMID: 22407347 DOI: 10.1093/chromsci/bms012

A simple, fast, repeatable and less laborious sample preparation protocol was developed and applied for the analysis of biocontrol fungus Trichoderma harzianum strain FA1132 by using gas chromatography-mass spectrometry. The match factors for sample spectra with respect to the mass spectra library of fungal volatile compounds were determined and used to study the complex hydrocarbons and other volatile compounds, which were separated by using different capillary columns with nonpolar, medium polar and high polar stationary phases. To date, more than 278 volatile compounds (with spectral match factor at least 90%) such as normal saturated hydrocarbons (C7-C30), cyclohexane, cyclopentane, fatty acids, alcohols, esters, sulfur-containing compounds, simple pyrane and benzene derivatives have been identified. Most of these compounds have not previously been reported. The method described in this paper is a more convenient research tool for the detection of volatile compounds from the cultures of T. harzianum.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods*
Fulltext Detection of quorum sensing activity in the multidrug-resistant clinical isolate Pseudomonas aeruginosa strain GB11

Cheng HJ, Ee R, Cheong YM, Tan WS, Yin WF, Chan KG

Sensors (Basel), 2014;14(7):12511-22.
PMID: 25019635 DOI: 10.3390/s140712511

A multidrug-resistant clinical bacteria strain GB11 was isolated from a wound swab on the leg of a patient. Identity of stain GB11 as Pseudomonas aeruginosa was validated by using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Detection of the production of signaling molecules, N-acylhomoserine lactones (AHLs), was conducted using three different bacterial biosensors. A total of four different AHLs were found to be produced by strain GB11, namely N-butyryl homoserine lactone (C4-HSL), N-hexanoylhomoserine lactone (C6-HSL), N-octanoyl homoserine lactone (C8-HSL) and N-3-oxo-dodecanoylhomoserine lactone (3-oxo-C12-HSL) using high resolution liquid chromatography tandem mass spectrometry (LC-MS/MS). Of these detected AHLs, 3-oxo-C12-HSL was found to be the most abundant AHL produced by P. aeruginosa GB11.

Matched MeSH terms: Tandem Mass Spectrometry/methods
Fulltext Tandem mass spectrometry detection of quorum sensing activity in multidrug resistant clinical isolate Acinetobacter baumannii

Chan KG, Cheng HJ, Chen JW, Yin WF, Ngeow YF

ScientificWorldJournal, 2014;2014:891041.
PMID: 25101326 DOI: 10.1155/2014/891041

Many Proteobacteria communicate via production followed by response of quorum sensing molecules, namely, N-acyl homoserine lactones (AHLs). These molecules consist of a lactone moiety with N-acyl side chain with various chain lengths and degrees of saturation at C-3 position. AHL-dependent QS is often associated with regulation of diverse bacterial phenotypes including the expression of virulence factors. With the use of biosensor and high resolution liquid chromatography tandem mass spectrometry, the AHL production of clinical isolate A. baumannii 4KT was studied. Production of short chain AHL, namely, N-hexanoyl-homoserine lactone (C6-HSL) and N-octanoyl-homoserine lactone (C8-HSL), was detected.

Matched MeSH terms: Tandem Mass Spectrometry/methods*
Sol-gel hybrid methyltrimethoxysilane-tetraethoxysilane as a new dispersive solid-phase extraction material for acrylamide determination in food with direct gas chromatography-mass spectrometry analysis

Omar MM, Wan Ibrahim WA, Elbashir AA

Food Chem, 2014 Sep 1;158:302-9.
PMID: 24731346 DOI: 10.1016/j.foodchem.2014.02.045

A sol-gel hybrid sorbent, methyltrimethoxysilane-tetraethoxysilane (MTMOS-TEOS) was successfully used as new dispersive solid phase extraction (dSPE) sorbent material in the determination of acrylamide in several Sudanese foods and analysis using GC-MS. Several important dSPE parameters were optimised. Under the optimised conditions, excellent linearity (r(2)>0.9998) was achieved using matrix matched standard calibration in the concentration range 50-1000 μg kg(-1). The limits of detection (LOD) and limit of quantification ranged from 9.1 to 12.8 μg/kg and 27.8-38.9 μg/kg, respectively. The precision (RSD%) of the method was ⩽6.6% and recoveries of acrylamide obtained were in the range of 88-103%, (n=3). The LOD obtained is comparable with the LODs of primary secondary amine dSPE. The proposed MTMOS-TEOS dSPE method is direct and safe for acrylamide analysis, showed reliable method validation performances and good cleanup effects. It was successfully applied to the analysis of acrylamide in real food samples.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods*
Capillary electrophoresis for the analysis of paralytic shellfish poisoning toxins in shellfish: comparison of detection methods

Keyon AS, Guijt RM, Gaspar A, Kazarian AA, Nesterenko PN, Bolch CJ, et al.

Electrophoresis, 2014 May;35(10):1496-503.
PMID: 24591173 DOI: 10.1002/elps.201300353

Paralytic shellfish toxins (PSTs) are produced by marine and freshwater microalgae and accumulate in shellfish including mussels, oysters, and scallops, causing possible fatalities when inadvertently consumed. Monitoring of PST content of shellfish is therefore important for food safety, with currently approved methods based on HPLC, using pre- or postcolumn oxidation for fluorescence detection (HPLC-FLD). CE is an attractive alternative for screening and detection of PSTs as it is compatible with miniaturization and could be implemented in portable instrumentation for on-site monitoring. In this study, CE methods were developed for C(4) D, FLD, UV absorption detection, and MS-making this first report of C(4) D and FLD for PSTs detection. Because most oxidized toxins are neutral, MEKC was used in combination with FLD. The developed CZE-UV and CZE-C(4) D methods provide better resolution, selectivity, and separation efficiency compared to CZE-MS and MEKC-FLD. The sensitivity of the CZE-C(4) D and MEKC-FLD methods was superior to UV and MS, with LOD values ranging from 140 to 715 ng/mL for CZE-C(4) D and 60.9 to 104 ng/mL for MEKC-FLD. With the regulatory limit for shellfish samples of 800 ng/mL, the CZE-C(4) D and MEKC-FLD methods were evaluated for the screening and detection of PSTs in shellfish samples. While the CZE-C(4) D method suffered from significant interferences from the shellfish matrix, MEKC-FLD was successfully used for PST screening of a periodate-oxidized mussel sample, with results confirmed by HPLC-FLD. This confirms the potential of MEKC-FLD for screening of PSTs in shellfish samples.

Matched MeSH terms: Mass Spectrometry/methods*
Proteomic analysis of antihypertensive proteins in edible mushrooms

Lau CC, Abdullah N, Shuib AS, Aminudin N

J Agric Food Chem, 2012 Dec 19;60(50):12341-8.
PMID: 23190208 DOI: 10.1021/jf3042159

Mushrooms are high in protein content, which makes them potentially a good source of antihypertensive peptides. Among the mushrooms tested, protein extracts from Pleurotus cystidiosus (E1Pc and E5Pc) and Agaricus bisporus (E1Ab and E3Ab) had high levels of antihypertensive activity. The protein extracts were fractionated by reverse-phase high-performance liquid chromatography (RPHPLC) into six fractions. Fraction 3 from E5Pc (E5PcF3) and fraction 6 from E3Ab (E3AbF6) had the highest antihypertensive activities. SDS-PAGE analysis showed E5PcF3 consisted mainly of low molecular weight proteins, whereas E3AbF6 contained a variety of high to low molecular weight proteins. There were 22 protein clusters detected by SELDI-TOF-MS analysis with five common peaks found in E5PcF3 and E3AbF6, which had m/z values in the range of 3940-11413. This study suggests that the antihypertensive activity in the two mushroom species could be due to proteins with molecular masses ranging from 3 to 10 kDa.

Matched MeSH terms: Mass Spectrometry/methods
Fulltext Headspace solid-phase microextraction gas chromatography-mass spectrometry and gas chromatography-olfactometry analysis of volatile compounds in pineapple breads

Ying S, Lasekan O, Naidu KR, Lasekan S

Molecules, 2012 Nov 22;17(12):13795-812.
PMID: 23174897 DOI: 10.3390/molecules171213795

Sensorial analysis of pineapple breads (conventionally baked, Cpb; fully baked frozen, Fpb and partially baked, Ppb) showed no significant differences in terms of aroma and taste. On the contrary, the scores for the overall quality between the partially baked and conventionally baked breads showed significant (p < 0.05) differences. At the same time, headspace analysis using a solid-phase microextraction (SPME) method identified 59 volatile compounds. The results of the aroma extracts dilution analysis (AEDA) revealed 19 most odour-active compounds with FD factors in the range of 32-128 as the key odourants of the pineapple breads. Further analysis of the similarities and differences between the pineapple breads in terms of the key odourants were carried out by the application of PLS-DA and PLS-regression coefficients. Results showed that Ppb exhibited strong positive correlations with most of the volatile- and non-volatile compounds, while the Cpb showed significant positive correlations with hexanal and 4-hydroxy-2,5-dimethyl-3(2H)-furanone, and the Fpb had strong positive correlations with lactic acid, benzoic acid, benzaldehyde and ethyl propanoate.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods*
Determination of hair nicotine by gas chromatography-mass spectrometry

Man CN, Ismail S, Harn GL, Lajis R, Awang R

J Chromatogr B Analyt Technol Biomed Life Sci, 2009 Jan 15;877(3):339-42.
PMID: 19109080 DOI: 10.1016/j.jchromb.2008.12.014

Hair nicotine is a known biomarker for monitoring long-term environmental tobacco smoke (ETS) exposure and smoking status. In general, hair nicotine assay involves alkaline digestion, extraction and instrumental analysis. The gas chromatography-mass spectrometry (GC-MS) assay currently developed has shown to be of high throughput with average approximately 100 hair samples being extracted and analyzed per day. This was achieved through simplified extraction procedure and shortened GC analysis time. The extraction was improved by using small volume (0.4 mL) of organic solvent that does not require further evaporation and salting steps prior to GC-MS analysis. Furthermore, the amount of hair utilized in the extraction was very little (5 mg) while the sensitivity and selectivity of the assay is equal, if not better than other established methods. The linearity of the assay (r(2)>0.995), limit of quantitation (0.04 ng/mg hair), within- and between-assays accuracies and precisions (<11.4%) and mean recovery (92.6%) were within the acceptable range.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry*
Development of a simultaneous liquid-liquid extraction and chiral derivatization method for stereospecific GC-MS analysis of amphetamine-type stimulants in human urine using fractional factorial design

Aasim WR, Gan SH, Tan SC

Biomed Chromatogr, 2008 Sep;22(9):1035-42.
PMID: 18655218 DOI: 10.1002/bmc.1073

A stereospecific gas chromatography-mass spectrometry analysis method for amphetamine-type stimulants in human urine was recently developed. For maximum efficiency, liquid-liquid extraction and chiral derivatization of the analytes using (R)-(-)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride were performed simultaneously. The effects of (1) use of saturated sodium chloride in 2.0 M sodium hydroxide, (2) extraction solvent volume, (3) percentage of triethylamine, (4) derivatization reagent volume, (5) sample mixing time, (6) incubation temperature and (7) incubation time on method sensitivity and variability were assessed using a two-level, eight-run Plackett-Burman design followed by a fold-over design. The use of saturated sodium chloride solution and the derivatization reagent volume were significant factors (ANOVA, p<0.01). The saturated sodium chloride solution decreased sensitivity whereas an increased volume of derivatization reagent increased sensitivity. Calibration curves for all analytes were linear between 5 and 500 microg/L, with correlation coefficients of >0.99. Detection limits were

Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods*
Nutrient improvement using statistical optimization for growth of Schizophyllum commune, and its antifungal activity against wood degrading fungi of rubberwood

Teoh YP, Don MM, Ujang S

Biotechnol Prog, 2012 Jan-Feb;28(1):232-41.
PMID: 21990033 DOI: 10.1002/btpr.714

Two statistical tools, Plackett-Burman design (PBD) and Box-Behnken design (BBD) were used to optimize the mycelia growth of Schizophyllum commune with different nutrient components. Results showed that 32.92 g/L of biomass were produced using a medium consisting of 18.74 g/L yeast extract, 38.65 g/L glucose, and 0.59 g/L MgSO(4).7H(2)O. The experimental data fitted well with the model predicted values within 0.09 to 0.77% error. The biomass was also tested for antifungal activity against wood degrading fungi of rubberwood. Results showed that the minimum inhibitory concentration (MIC) values for antifungal activity range from 0.16 to 5.00 μg/μL. The GC-MS analysis indicated that this fungus produced several compounds, such as glycerin, 2(3H)-furanone, 5-heptyldihydro-, 4H-pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl-, and triacetin.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods
An unbiased approach for analysis of protein glycosylation and application to influenza vaccine hemagglutinin

An Y, Cipollo JF

Anal Biochem, 2011 Aug 1;415(1):67-80.
PMID: 21545787 DOI: 10.1016/j.ab.2011.04.018

Here a mass spectrometry-based platform for the analysis of glycoproteins is presented. Glycopeptides and released glycans are analyzed, the former by quadrupole orthogonal time-of-flight liquid chromatography/mass spectrometry (QoTOF LC/MS) and the latter by permethylation analysis using matrix-assisted laser desorption/ionization (MALDI)-TOF MS. QoTOF LC/MS analysis reveals the stochastic distribution of glycoforms at occupied sequons, and the latter provides a semiquantitative assessment of overall protein glycosylation. Hydrophilic interaction chromatography (HILIC) was used for unbiased enrichment of glycopeptides and was validated using five model N-glycoproteins bearing a wide array of glycans, including high-mannose, complex, and hybrid subtypes such as sulfo and sialyl forms. Sialyl and especially sulfated glycans are difficult to analyze because these substitutions are labile. The conditions used here allow detection of these compounds quantitatively, intact, and in the context of overall glycosylation. As a test case, we analyzed influenza B/Malaysia/2506/2004 hemagglutinin, a component of the 2006-2007 influenza vaccine. It bears 11 glycosylation sites. Approximately 90% of its glycans are high mannose, and 10% are present as complex and hybrid types, including those with sulfate. The stochastic distribution of glycoforms at glycosylation sites is revealed. This platform should have wide applications to glycoproteins in basic sciences and industry because no apparent bias for any glycoforms is observed.

Matched MeSH terms: Mass Spectrometry/methods
Simple, rapid and sensitive assay method for simultaneous quantification of urinary nicotine and cotinine using gas chromatography-mass spectrometry

Man CN, Gam LH, Ismail S, Lajis R, Awang R

J Chromatogr B Analyt Technol Biomed Life Sci, 2006 Dec 5;844(2):322-7.
PMID: 16908224

Nicotine is a major addictive compound in cigarette. Its smoke is rapidly and extensively metabolized to several metabolites in human. Cotinine as a major metabolite of nicotine is commonly used as a biomarker to determine active and passive smokers. Cotinine has a longer half-life ( approximately 20 h) compared to nicotine ( approximately 2h). A simple, sensitive, rapid and high throughput GC-MS method was developed for simultaneous quantification of urinary nicotine and cotinine in passive and active smokers. In the sample preparation method, the analytes and internal standard were first basified and followed by liquid-liquid extraction. Upon completion, anhydrous sodium sulphate was added to the solvent mixture to trap moistures. The clear extract obtained was directly injected into GC-MS, operating under selective ion monitoring (SIM) mode. Calibration curves in the range of 0.5-5000 ng/mL of the analytes in urine matrix were established with linear correlation coefficients (r(2)) greater than 0.997. The limit of detection for both nicotine and cotinine were 0.20 ng/mL. The mean recoveries for nicotine and cotinine were 93.0 and 100.4%, respectively. The within- and between-assay accuracies were between 2.1 and 7.9% for nicotine and between 0.7 and 11.1% for cotinine. Within- and between-assay precisions of 3.3-9.5% for nicotine and 3.4-9.8% for cotinine were also achieved. The method can be used in routine assessment and monitoring of active smoking and exposure to environmental tobacco smoke. The applicability of the assay was demonstrated in a small-scale comparison study between smokers and non-smokers.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods*
Structure of the d(CGCGAATTCGCG)2 complex of the minor groove binding alkylating agent alkamin studied by mass spectrometry

Majid AM, Smythe G, Denny WA, Wakelin LP

Mol Pharmacol, 2007 Apr;71(4):1165-78.
PMID: 17251328

Nitrogen mustard alkylating agents are important cancer drugs. Much interest has been focused on redirecting their covalent adducts from the N7 atoms of guanine in the major groove of DNA to the N3 atoms of adenine in the minor groove by attaching mustard groups to AT-selective minor groove binding ligands. Here we describe the use of electrospray ionization and matrix-assisted laser desorption ionization/time-of-flight mass spectrometry to study the structure of the DNA complexes of two minor groove binding polybenzamide mustards, alkamin and alkamini; the former is a bis-half-mustard in which reactive groups are disposed at each end of the ligand, and the latter is its monofunctional analog. Alkamin is potently cytotoxic and active in experimental mouse tumor models, whereas alkamini is not. We have studied their interaction with the DNA dodecamer d(CGCGAATTCGCG)(2), designated A2T2, and we provide a detailed analysis of the observed DNA-ligand adduct ions and their fragmentation products. We find that alkamini alkylates A2T2 at guanine G4 and adenines A5 and A6 in a manner consistent with covalent attack on purine N3 atoms from the minor groove of the AT tract. Alkamin also forms monofunctional adducts at G4 and both adenines in which the second mustard arm is hydrolyzed but, in addition, forms a variety of interstrand cross-links between adenines A5/A6 and A5'/A6', an interstrand cross-link between G4 and A6', and an intrastrand cross-link between G4 and A6. We conclude that the marked cytotoxicity of alkamin and its experimental antitumor activity could be the consequence of its ability to cross-link cellular DNA at AT tract sequences.

Matched MeSH terms: Mass Spectrometry/methods
Rapid identification of pork for halal authentication using the electronic nose and gas chromatography mass spectrometer with headspace analyzer

Nurjuliana M, Che Man YB, Mat Hashim D, Mohamed AK

Meat Sci, 2011 Aug;88(4):638-44.
PMID: 21420795 DOI: 10.1016/j.meatsci.2011.02.022

The volatile compounds of pork, other meats and meat products were studied using an electronic nose and gas chromatography mass spectrometer with headspace analyzer (GCMS-HS) for halal verification. The zNose™ was successfully employed for identification and differentiation of pork and pork sausages from beef, mutton and chicken meats and sausages which were achieved using a visual odor pattern called VaporPrint™, derived from the frequency of the surface acoustic wave (SAW) detector of the electronic nose. GCMS-HS was employed to separate and analyze the headspace gasses from samples into peaks corresponding to individual compounds for the purpose of identification. Principal component analysis (PCA) was applied for data interpretation. Analysis by PCA was able to cluster and discriminate pork from other types of meats and sausages. It was shown that PCA could provide a good separation of the samples with 67% of the total variance accounted by PC1.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods*
Fulltext Psychoactive plant abuse: the identification of mitragynine in ketum and in ketum preparations

Chan KB, Pakiam C, Rahim RA

Bull Narc, 2005;57(1-2):249-56.
PMID: 21338025

Recently, the abuse of ketum, an indigenous psychoactive plant, has received a lot of attention in Malaysia. To help national law enforcement agencies control its abuse, the laboratory of the Forensic Division has developed a procedure for its positive identification. Botanical identification may not be practical or conclusive, owing to the wide range of ketum materials available on the market, including dry macerated leaves, powdered leaves and drinks. In order to confirm that a substance is, in fact, ketum or that a preparation is derived from ketum, gas chromatography-mass spectrometry is used to definitively identify the presence of the psychoactive principle mnitragynine.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods
Gas Chromatography-Mass Spectrometry (GC-MS) Analysis of Scaphium Affine Seed Extract and Assessment of Its Anti-hemorrhoidal Efficacy

Abbas SA, Khan A, Fatima M, Kalusalingam A, Kanakal MM, Inamdar SK, et al.

Antiinflamm Antiallergy Agents Med Chem, 2024;23(2):118-128.
PMID: 38357954 DOI: 10.2174/0118715230285370240131111539

BACKGROUND: Seeds of plant Scaphium affine are traditionally used by the healers of "India" for the treatment of piles.
OBJECTIVES: The primary objective of the study was to assess the anti-hemorrhoidal potential of the ethanolic seed extract of Scaphium affine.
METHODS: After the soxhlet extraction method, the seed extract from Scaphium affine was first submitted to phytochemical standardization and then GC-MS analysis. Rats were given Croton oil and Jatropha oil to develop hemorrhoids, and Scaphium affine seed extract (ESA) was administered orally for 5 days and 3 days, respectively, at doses of 1000 and 500 mg/kg. The Rectoanal coefficient (RAC) was calculated as an inflammatory marker. The hemorrhoidal tissues were also subjected to cytokine profiling, biochemical estimation and histopathology.
RESULTS: ESA demonstrated the presence of flavonoids, saponins, phytosterols, phenols, and tannins. GCMS analysis elucidated the presence of hexadecanoic acid 2 hydroxy -1,3 propane diyl ester,9 Octadecanoic acid ethyl ester, Cyclohexane 1,4 di methyl cis, Farnesol isomer,1, E-11, Z-13 octa decatriene, Stigmasterol, N-(5 ethyl -1,3,4-thiadiazol-yl) benzamide, N, N Dinitro 1,3,5,7 tetraza bicyclo 93,3,1) as major phytoconstituents. The results depicted more potent anti-hemorrhoidal activity of ESA at 1000 mg/kg, p.o., which was evident through a decrease in RAC. A significant decline in the levels of IL-1β, IL-6, and TNF-α expression was observed, along with the restoration of altered antioxidants and enzymes. Histopathological analysis confirmed the tissue recovery as it revealed minimal inflammation and decreased dilated blood vessels in treated animals.
CONCLUSION: Based on the results it can be concluded that seeds of Scaphium affine showed significant anti-hemorrhoid agents which may be attributed to their anti-inflammatory and anti-oxidant potential due to the presence of certain phytoconstituents in it. The study also supports the traditional use of seeds of Scaphium affine for the first time in the treatment of hemorrhoids.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry*
Fulltext Rapid and simultaneous quantification of levetiracetam and its carboxylic metabolite in human plasma by liquid chromatography tandem mass spectrometry

Yeap LL, Lo YL

PLoS One, 2014;9(11):e111544.
PMID: 25375249 DOI: 10.1371/journal.pone.0111544

A simple liquid chromatography tandem mass spectrometry method was developed and validated according to the guidelines of the US Food and Drug Administration and the European Medicines Agency for a simultaneous quantification of levetiracetam (LEV) and its metabolite, UCB L057 in the plasma of patients. A 0.050 mL plasma sample was prepared by a simple and direct protein precipitation with 0.450 mL acetonitrile (ACN) containing 1 µg/mL of internal standard (IS, diphenhydramine), then vortex mixed and centrifuged. A 0.100 mL of the clear supernatant was diluted with 0.400 mL water and well mixed. A 0.010 mL of the resultant solution was injected into an Agilent Zorbax SB-C18 (2.1 mm×100 mm, 3.5 µm) column with an isocratic elution at 0.5 mL/min using a mixture of 0.1% formic acid in water and ACN (40:60 v/v). Detection was performed using an AB Sciex API 3000 triple quadrupole mass spectrometer, equipped with a Turbo Ion Spray source, operating in a positive mode: LEV at transition 171.1>154.1, UCB L057 at 172.5>126.1, and IS at 256.3>167.3; with an assay run time of 2 minutes. The lower limit of quantification (LLOQ) for both LEV and UCB L057 was validated at 0.5 µg/mL, while their lower limit of detection (LOD) was 0.25 µg/mL. The calibration curves were linear between 0.5 and 100 µg/mL for both analytes. The inaccuracy and imprecision of both intra-assay and inter-assay were less than 10%. Matrix effects were consistent between sources of plasma and the recoveries of all compounds were between 100% and 110%. Stability was established under various storage and processing conditions. The carryovers from both LEV and UCB L057 were less than 6% of the LLOQ and 0.13% of the IS. This assay method has been successfully applied to a population pharmacokinetic study of LEV in patients with epilepsy.

Matched MeSH terms: Tandem Mass Spectrometry*
Fulltext Antimicrobial compounds from leaf extracts of Jatropha curcas, Psidium guajava, and Andrographis paniculata

Rahman MM, Ahmad SH, Mohamed MT, Ab Rahman MZ

ScientificWorldJournal, 2014;2014:635240.
PMID: 25250382 DOI: 10.1155/2014/635240

The present research was conducted to discover antimicrobial compounds in methanolic leaf extracts of Jatropha curcas and Andrographis paniculata and ethanolic leaf extract of Psidium guajava and the effectiveness against microbes on flower preservative solution of cut Mokara Red orchid flowers was evaluated. The leaves were analyzed using gas chromatography-mass spectrometry. A total of nine, 66, and 29 compounds were identified in J. curcas, P. guajava, and A. paniculata leaf extracts, with five (88.18%), four (34.66%), and three (50.47%) having unique antimicrobial compounds, respectively. The experimental design on vase life was conducted using a completely randomized design with 10 replications. The flower vase life was about 6 days in the solution containing the P. guajava and A. paniculata leaf extracts at 15 mg/L. Moreover, solution with leaf extracts of A. paniculata had the lowest bacterial count compared to P. guajava and J. curcas. Thus, these leaf extracts revealed the presence of relevant antimicrobial compounds. The leaf extracts have the potential as a cut flower solution to minimize microbial populations and extend flower vase life. However, the activities of specific antimicrobial compounds and double or triple combination leaf extracts to enhance the effectiveness to extend the vase life need to be tested.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods
Assessment of dispersive liquid-liquid microextraction conditions for gas chromatography time-of-flight mass spectrometry identification of organic compounds in honey

Moniruzzaman M, Rodríguez I, Rodríguez-Cabo T, Cela R, Sulaiman SA, Gan SH

J Chromatogr A, 2014 Nov 14;1368:26-36.
PMID: 25441341 DOI: 10.1016/j.chroma.2014.09.057

The suitability of the dispersive liquid-liquid microextraction (DLLME) technique for gas chromatography (GC) characterization of minor organic compounds in honey samples is evaluated. Under optimized conditions, samples were pre-treated by liquid-liquid extraction with acetonitrile followed by DLLME using carbon tetrachloride (CCl4, 0.075 mL) as extractant. The yielded settled phase was analyzed by GC using high resolution time-of-flight (TOF) mass spectrometry (MS). The whole sample preparation process is completed in approximately 10 min, with a total consumption of organic solvents below 4 mL, relative standard deviations lower than 12% and with more than 70 organic compounds, displaying linear retention index in the range from 990 to 2900, identified in the obtained extracts. In comparison with HS SPME extraction, higher peak intensities were attained for most volatile and semi-volatile compounds amenable to both extraction techniques. Furthermore, other species such as highly polar and water soluble benzene acids, long chain fatty acids, esters and flavonoids, which are difficult to concentrate by HS SPME, could be identified in DLLME extracts. Some of the compounds identified in DLLME extracts have been proposed as useful for samples classification and/or they are recognized as markers of honeys from certain geographic areas.

Matched MeSH terms: Gas Chromatography-Mass Spectrometry/methods*

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