Top PDF Ion mobility spectrometry–mass spectrometry (IMS–MS) for on- and offline analysis of atmospheric gas and aerosol species

Ion mobility spectrometry–mass spectrometry (IMS–MS) for on- and offline
analysis of atmospheric gas and aerosol species

Ion mobility spectrometry–mass spectrometry (IMS–MS) for on- and offline analysis of atmospheric gas and aerosol species

Ion mobility spectrometry (IMS) is a well-established sep- aration technique, the principles of which were first laid out in 1903 (Thomson, 1903). Previously known as plasma chro- matography or gaseous electrophoresis (Karasek, 1974), IMS has gained prominence and utility over the last 15 years with rapidly increasing numbers of commercially avail- able instruments (Eiceman et al., 2013). IMS separates gas- phase ions based on a property known as ion mobility, K, which is sensitive to molecular structure (i.e., ion size and shape/conformation) and ion–molecule interactions with a buffer gas such as nitrogen, helium, or air. Since IMS sep- arations are based on gas-phase mobility rather than polar- ity, they are not limited by solvent- or stationary-phase con- straints. Thus, IMS can be used to separate species with different structures that are not easily separated by LC and GC techniques. Such species include isomers, which are species with the same atomic composition arranged in dif- ferent structures, and isobars, which are compounds of dif- ferent atomic composition but have overlapping mass num- bers (McNaught and Wilkinson, 2014). In fact, IMS–MS (IMS separation coupled with mass spectrometric detection of ions) has been demonstrated as a powerful replacement for LC/MS in complex fields of analysis such as lipids, metabolites, water quality, and pharmaceuticals (Dwivedi et al., 2008; Groessl et al., 2015; Jarrold, 2000; Kanu et al., 2008).
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Aqueous-phase photooxidation of levoglucosan – a mechanistic study using aerosol time-of-flight chemical ionization mass spectrometry (Aerosol ToF-CIMS)

Aqueous-phase photooxidation of levoglucosan – a mechanistic study using aerosol time-of-flight chemical ionization mass spectrometry (Aerosol ToF-CIMS)

The decay of LG can be explained by several pathways. Heterogeneous oxidation of LG by gas-phase oxidants has been studied in the laboratory (Kessler et al., 2010; Hennigan et al., 2010; Knopf et al., 2011), where it has been demon- strated that particle-phase LG can be oxidized by hydroxyl (OH) radicals efficiently, leading to LG lifetimes on the or- der of days. More recently, gas-phase oxidation has also been proposed to contribute to LG loss (May et al., 2012). A small fraction of particle-phase LG can volatilize into the gas phase where it is oxidized efficiently. A third explanation for the observed LG decay is reactive loss in the aqueous phase, such as cloud water or aqueous aerosol particles. Studies from the past decade have revealed the atmospheric aque- ous phase as an important reaction medium where organic compounds can be processed, leading to formation and ag- ing of SOA (Blando and Turpin, 2000; Ervens et al., 2011). BB particles can be hygroscopic, depending on their size and inorganic composition (Petters and Kreidenweis, 2007; Pet- ters et al., 2009); therefore, a highly functionalized and wa- ter soluble organic species, such as LG, can be subject to aqueous-phase processing. Two laboratory studies have in- vestigated the kinetics of aqueous-phase OH oxidation of LG (Hoffmann et al., 2010; Teraji and Arakaki, 2010), finding that OH is the main sink for LG in the tropospheric aque- ous phase with lifetimes on the order of hours. By contrast, little is known of the aqueous-phase reaction mechanism of LG. The only studies are those of Holmes and Petrucci who investigated acid-catalyzed and OH-induced oligomerization (Holmes and Petrucci, 2006, 2007) and a recent theoretical study of possible reaction pathways (Bai et al., 2013).
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Elemental analysis of aerosol organic nitrates with electron ionization high-resolution mass spectrometry

Elemental analysis of aerosol organic nitrates with electron ionization high-resolution mass spectrometry

Recently, the high resolution version of the AMS (HR- ToF-MS) has been used to determine elemental composi- tion of organic aerosol (Aiken et al., 2007, 2008). While the AMS is to first order equally sensitive to all NR aerosol (Jimenez et al., 2003), it is known to detect oxygen and nitro- gen with somewhat reduced efficiency relative to carbon and hydrogen. Aiken et al. (2008) used a series of organic stan- dards to determine calibrations for the calculation of O/C, H/C and N/C ratios from AMS data. This is possible with the HR-ToF-AMS because of its ability to distinguish differ- ent fragments with the same nominal mass, and compare the measured composition to the composition of the standards. These experiments did not include any organic nitrates be- cause semi-volatile organic nitrates were not commercially available. Other nitrogen containing organic compounds were tested including amine, amide nitro and pyradine com- pounds. In contrast to these species organic nitrates are rel- atively thermally unstable and are known to decompose at 300–400 ◦ C in 10’s of ms the gas phase at atmospheric pres- sure (Day et al., 2002). Thus their detection could be more significantly affected by the combination of flash volatiliza- tion/EI than these other nitrogen containing organics.
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Especiação química de arsênio em samambaia utilizando espectrometria de massas com ionização ambiente

Especiação química de arsênio em samambaia utilizando espectrometria de massas com ionização ambiente

The various chemical forms of arsenic compounds, including organic and inorganic species, exhibit different toxicities and environmental impacts. Ambient ionization mass spectrometry, such as DESI-MS (desorption electrospray ionization mass spectrometry), DESI-MSI (desorption electrospray ionization mass spectrometry imaging) and PS-MS (paper spray mass spectrometry), are excellent techniques for in situ analysis, under atmospheric pressure, at room temperature and low sample-consumption analysis to be performed with minimal sample pretreatment. These three techniques were applied for the rapid detection of inorganic compounds (arsenate - As (V) and arsenite - As (III)) and organic compounds (dimethylarsinic acid - DMA and disodium hexahydrate metilarsenate - MMA) of arsenic in fern leaves, aiming to expand applications for these techniques. Operating conditions of DESI-MS were optimized with DMA standard solution deposited on a paper surface to improve ionization efficiency. DESI-MS was applied to the fern leaves analysis artificially contaminated with As. Analyses in DESI-MSI were performed by the indirect method where the impression of fern leaf on a PTFE filter surface was made and the ions analyzed in the full scan mode. For PS-MS, fern leaf extract in methanol was placed in a triangular paper and analyzed. Mass spectra for all species of As were acquired in positive and negative ion mode and can confirm the presence of As (V) by ions of m/z 140,92, 142,93 e 160,94; As (III), by ions of m/z 106,91, 124,92, 126,94 e 144,95; DMA, by ions of m/z 138,97 e 156,98; and MMA, by ions of m/z 138,93, 140,95 e 158,96. For DESI-MS and PS-MS, MS/MS spectra were confirmed the identity of each As compound by the characteristic fragmentation profile. For the DESI-MSI, the confirmation was made by the mass error for each analyzed ion. The quantification of the As compounds by LC-ICP-MS confirmed the results obtined by three tecniques. Thus, it is possible demonstrate the applicability of the DESI-MS, DESI-MSI e PS- MS as rapid, simple, efficient and with little sample preparation for detecting arsenic compounds in complex matrices.
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J. Braz. Chem. Soc.  vol.27 número3

J. Braz. Chem. Soc. vol.27 número3

pulse sequences supplied by the manufacturer. The high resolution mass spectrometry (HRMS) using atmospheric pressure chemical ionization (HRAPCIMS) was performed on a liquid chromatography-mass spectrometry ion trap and time-of-flight (LCMS-IT-TOF, Shimadzu) spectrometer. The positive ion mass spectra were recorded in the m/z 200-700 range, using a potential of 4.0 kV on the capillary and He as the collision gas. The high performance liquid chromatography (HPLC) analysis was carried out using an ultra-fast liquid chromatography (UFLC, Shimadzu) system equipped with a SPD-M20A diode array UV-Vis detector and a Phenomenex C-18 column, 5 µm (4.6 × 250 mm 2 ).
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J. Braz. Chem. Soc.  vol.23 número1

J. Braz. Chem. Soc. vol.23 número1

50-1000 m/z range. ESI-MS/MS experiments were done by selecting the ion of interest using the first mass analyzing quadrupole. The selected ion was in turn subjected to 5-40 eV collisions with argon in the collision cell whereas the orthogonal TOF mass analyzer was used to acquire the ESI-MS/MS data. External calibration with a phosphoric acid solution was employed.

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Detection of SPM-1-Producing Pseudomonas aeruginosa and Class D beta-Lactamase-Producing Acinetobacter baumannii Isolates by Use of Liquid Chromatography-Mass Spectrometry and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry

Detection of SPM-1-Producing Pseudomonas aeruginosa and Class D beta-Lactamase-Producing Acinetobacter baumannii Isolates by Use of Liquid Chromatography-Mass Spectrometry and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry

The LC-MS and MALDI-TOF MS assays were performed by incubating fresh bacterial inoculums from Mueller-Hinton agar plates (Oxoid, Basingstoke, United Kingdom) in a buffer-adjusted solution (20 mM Tris-HCl, pH 6.8) with or without serial dilu- tions of ertapenem (0.12 to 0.5 ␮g/ml; Merck Sharp & Dohme, NJ) for periods of 2 and 4 h. This buffer solution was selected since a NaCl solution could inhibit the CHDL activity. After centrifu- gation, 1-␮l aliquots of each sample were overlaid with 1 ␮l of ␣-cyano-4-hydroxycinnamic acid matrix solution (HCCA; Bruker Daltonics, Bremen, Germany) and spotted onto a stainless steel MALDI target plate as recommended by the manufacturer. The mass spectrum was obtained by using a Bruker Daltonics Microflex LT instrument operating in linear, positive ion mode and using the Flex Control 3.3 software with the following instru- ment parameters: pulsed ion extraction delay, 30 ns; ion source voltage one, 20 kV; ion source voltage two, 18.65 kV; and ion source lens voltage, 7.00 kV. The mass spectrometer was cali- brated using the HCCA matrix peaks ([M⫹H] ⫹ ⫽ 189.17; [2 M⫹H] ⫹
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Determination of plasticizers in drinking water using gas chromatography and mass spectrometry.

Determination of plasticizers in drinking water using gas chromatography and mass spectrometry.

DETERMINATION OF PLASTICIZERS IN DRINKING WATER USING GAS CHROMATOGRAPHY AND MASS SPECTROMETRY. This study investigated the levels of plasticizer endocrine disruptors (diethyl phthalate, dibutyl phthalate, and bisphenol A) in drinking water at Paraíba do Sul River region and release of these compounds from bottled water. An analytical method employing solid phase extraction and GC/MS was optimized and validated. The results showed that the method is selective, linear (r² > 0.99), precise (RSD <12%), accurate (recoveries between 62 and 105%), sensitive and robust. Applying the method, the presence of all studied pollutants in drinking water was observed for the three sampled plasticizers. These plasticizers were not found in mineral bottled water, before or after storage.
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Ion mobility spectrometry: the diagnostic tool of third millennium medicine

Ion mobility spectrometry: the diagnostic tool of third millennium medicine

Instrumental breath diagnosis is a new area of re- search with a promising clinical potential with fast real-time analysis of metabolites in exhaled breath. The method is based on the detection of natural vol- atile metabolites in breath, in healthy states or from diseases, and metabolites from contamination or produced by microbiota in the respiratory system. IMS provides insight on perturbations of the human exposome through breath measurements that can be interpreted as preclinical signals of adverse out- come pathways. Oxidative stress status may be mon- itored via volatile products of lipid peroxidation, and phenotypic information, important in personalized medicine, is obtained from the measurement of the activity of enzymes such as dihydropyrimidine dehy-
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A REVIEW ON MASS SPECTROMETRY DETECTORS

A REVIEW ON MASS SPECTROMETRY DETECTORS

At present, routine DNA analysis is done by mass spectrometry is seriously constrained to small DNA fragments and the application of mass spectrometry on those procedures that identify short DNA sequences. This approach helps the molecular biologists which are associated with LBL’s Human Genome Center to identify redundant DNA sequences and vector contamination in clones, thereby improving sequencing efficiency. With the use of conventional electron multipliers one of the limitation of mass spectrometry in DNA analysis is its poor efficiency .To solve this problem, alternative detection schemes which works on heat pulse detection is developed. When ions strike a detector, the kinetic energy of striking ions is converted into heat and then measures indirectly such heat pulses. Developing a type of cryogenic detector (as given in figure 19) called a superconducting tunnel junction device which produced photons when ions strike the detector. This detector does not base on the principle of the production of secondary electrons. This type of detector to be at least two order of magnitude which is more sensitive, on an area-normalized basis, than micro channel plate ion detectors. These detectors could extend the upper mass limit large ions. In this electro spray ion sources generate ions of mega-Dalton DNA with minimum fragmentation, but the mass spectrometric analysis of these large ions usually leads only to a mass/charge distribution. If charge of ion was known, actual mass data could be determined. To solve this problem, develop a detector that will measure the velocity and charge of individual ions. Mass analyze DNA molecules in the 1 to 10 Mega Dalton range using charge-detection mass spectrometry. In this technique, individual electro spray ions are strike through a metal tube which detects their image charge. When ions of known energy are sampled than simultaneous measurement of their velocity provides a way to measure their mass. By this method several thousand of ions can be analyzed in a few minutes, thus generating statistically significant mass values regarding the ions in a sample population 25 .
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Time-of-Flight Secondary Ion Mass Spectrometry: New application for urinary stones analysis

Time-of-Flight Secondary Ion Mass Spectrometry: New application for urinary stones analysis

Usually about 98–99% of the filtered load of those amino acids is reabsorbed in the proximal tubule [100]. The defect of the transporter causes a dramatic increase in urinary concentration of these substances while serum concentration is reported to just drop by 20 –30% [101]. Although all of these amino acids reach high concentrations within the urine, only cystine is insoluble enough to form stones. Cystine is poorly soluble at physiological urine pH values between 5 and 7, and stones are formed especially at concentrations exceeding 240 –300 mg/L (1.33–1.66 mmol/L). Higher pH values >8 lead to a threefold increase of cystine solubility [102]. Other known and yet unknown factors seem to play a role since the effect of pH on cystine solubility varies among patients [103-105]. Factors known to influence cystine excretion are dietary salt and animal protein intake. Both increase cystine excretion, yet no prospective studies have demonstrated changes in stone activity as a result of sodium restricted diets [103]. As for protein intake, just one study demonstrated that lowering intake of cystine’s dietary precursor methionine reduces urinary cystine excretion [106]. Stones of cystine have a typical yellow color and a wax- like surface. The consistency is very solid [89].
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Application of gas chromatography-mass spectrometry for targeted and non-targeted analysis in toxic and edible mushrooms

Application of gas chromatography-mass spectrometry for targeted and non-targeted analysis in toxic and edible mushrooms

Beyond participating in all these processes, macrofungi, specifically their fruiting bodies, integrate the food chains of some animals and are part of the human diet (micophagy) [2] . Furthermore, mushrooms of some species are highly appreciated by humans due to their organoleptic properties (taste, smell and texture) [7, 8] . Furthermore, they are high nutritional value food, as they are rich in proteins, amino acids (AA), vitamins and minerals and have low lipid and caloric contents. [8-10] Hence, these macrofungal species have high gastronomic and economic values. Among these species, the mycorrhizal ones are more valorised because they are difficult to produce in culture. In this context, truffles (fruiting bodies of the species belonging to genus Tuber P. Micheli ex F.H. Wigg.) are the most appreciated and, consequently, they have expensive prices. The most expensive price of the “white truffle”, also known as “Alba Madonna” (Tuber magnatum Pico & Vitt.), may reach 17.500€/kg. In Portugal, Boletus edulis Bull., Cantharellus cibarius Fr. and Amanita caesarea (Scop.) are, economically, the most important species, with prices in the range of 15-30€/kg. [2, 11]
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Development and validation of a methodology FOR analysis of biodiesel: diesel blends using gas chromatography-mass spectrometry.

Development and validation of a methodology FOR analysis of biodiesel: diesel blends using gas chromatography-mass spectrometry.

DEVELOPMENT AND VALIDATION OF A METHODOLOGY FOR ANALYSIS OF BIODIESEL: DIESEL BLENDS USING GAS CHROMATOGRAPHY-MASS SPECTROMETRY. The aim of this work was to develop and validate a method of analysis of biodiesel:diesel blends using HRGC-MS in SIM mode. The proposed method is applicable to biodiesel from linoleic oils, such as soybean oil. The following results were obtained: linearity over the methyl linoleate concentration range of 250-2500 mg L -1 (R 2 > 0.999);

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Quantification of acrylamide in foods selected by using gas chromatography tandem mass spectrometry

Quantification of acrylamide in foods selected by using gas chromatography tandem mass spectrometry

olo , p ečišća a je sa ast o o Ca ez I i II [ ], itd. )a k a tifika iju ak ila ida po oću GC–MS e g. gas h o atog aph – ass spe t o et ili LC–MS-MS e g. Li uid h o atog aph –ta de ass spe t o- et etode eći a ist aži ača p edlaže p ip e u uzo aka u iše faza. S e do sada pu liko a e GC–MS etode za od eđi a je ak ila ida u a i i a a ože o podeliti u d e katego ije, o e koje uključuju de i atiza iju i o e ez p i e e de i atiza ije. Metode za od eđi a je ak ila ida ez de i atiza ije zahte aju dugot aj e ekst ak ije koje ogu t ajati u eki slu- čaje i a i do deset da a [ ]. Metode sa de i atiza- ijo i aju p ed osti je o oguća aju k a tifika iju ak ila ida i do i oa t ago a [ – ]. Međuti , de i-
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Metabolic characterization of grapevine leaves: first clues towards biomarkers discovery

Metabolic characterization of grapevine leaves: first clues towards biomarkers discovery

major classes of compounds. On the other hand, considering the amount of chemical products leaves are exposed to, it is quite relevant to develop accurate detection techniques in order to assure that leaves are safe for consumption. Most studies at the metabolite level in plants for human consumption are based on targeted approaches, focusing on a certain class of compounds, particularly aminoacids, phenolic compounds and fatty acids (Harb et al., 2015; Liu et al., 2014). These studies were performed using one or a combination of analytical techniques like gas chromatography (GC), high performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), and GC or LC coupled to mass spectrometry (MS), without achieving a maximum metabolome coverage (Ali et al., 2012, 2009, Batovska et al., 2009, 2008; Figueiredo et al., 2008; Harb et al., 2015; Jorge et al., 2015; Liu et al., 2014; Rizzuti et al., 2013). Recent improvements have been made in order to have maximum metabolome coverage. Direct infusion Fourier transform ion cyclotron mass spectrometry (DI-FTICR-MS) presents high-resolution (more than 1,000,000) and ultra-high-mass accuracy (below 1 ppm) (Han et al., 2008) of each analyte in a compound mixture, without requiring any chromatographic separation step. Recently, our group has developed an efficient metabolite extraction protocol for grapevine leaves and identified 719 unique masses, corresponding to over 1300 putative metabolites (Maia et al., 2016). We were also able to detect several pesticides, such as fenthion, bromacil and terbacil, broadly used for parasite, insect and fungi control in grapevine. As the cultivated Vitis vinifera, is susceptible to several pathogens, the current strategy for disease control is the application of powerful fungicides and pesticides, which can remain in leaves for a long time. For example, in grapes the dissipation time for fungicides can reach 30 days until they are considered safe for consumption (Banerjee et al., 2008). Thus, it is crucial to have accurate methods for quality assessment of leaf composition.
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J. Braz. Chem. Soc.  vol.21 número4

J. Braz. Chem. Soc. vol.21 número4

the ICP-SFMS presented signal instabilities due to the methanol used in HPLC separation. The plasma in the ICP-SFMS extinguished with 20% (v/v) methanol using a Scott-type spray chamber refrigerated by cooled water, but supported up to 30% (v/v) with a cyclonic chamber refrigerated in an ice bath. Signals from MT isoforms separated by HPLC with detection by ICP-TOFMS presented the highest chromatographic resolution and stability demonstrating the good tolerance to methanol of this instrumental coniguration. Furthermore, the proposal of coupling to ICP-MS eficient nano-HPLC columns and nebulizers for online speciation analysis minimized the effect of the organic phase and extended its applicability to small sample volumes required for accurate analysis of proteins. 66,67 Applications included the determination of Cd,
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Analysis of Structure and Abrasion Resistance of the Metal Composite Based on an Intermetallic FeAl Phase with VC and TiC Precipitates

Analysis of Structure and Abrasion Resistance of the Metal Composite Based on an Intermetallic FeAl Phase with VC and TiC Precipitates

Intermetals are creep-resistant materials with unique properties intermediate between the properties of metals and ceramics. Their low density, high strength and resistance to oxidation, combined with sufficient ductility and fracture toughness, make them an attractive material for machine elements operating at elevated temperatures and in corrosive environments. Intermetallic phases based on Fe and Al (called intermetallics) are intermetallic compounds very interesting in terms of the technological properties, which combine the properties of metals and ceramics. From the Fe-Al phase equilibrium diagram it follows that the widest use could have two phases: FeAl and Fe 3 Al. Of these two phases, more useful seems be the FeAl
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Development and validation of a portable gas phase standard generation and calibration system for volatile organic compounds

Development and validation of a portable gas phase standard generation and calibration system for volatile organic compounds

Total carbon measurement by conversion to CO 2 and nondispersive infrared (NDIR) sensor analysis has long been used for analysis of a range of environmental samples ranging from natural waters to bulk collected aerosol particles. Total organic carbon (TOC) measurements of gas phase nonmethane hydrocarbons using oxidative cata- lysts, followed by reduction to methane, have been used in previous work (Maris et

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Elemental analysis of aerosol organic nitrates with electron ionization high-resolution mass spectrometry

Elemental analysis of aerosol organic nitrates with electron ionization high-resolution mass spectrometry

Aiken, A. C., Salcedo, D., Cubison, M. J., Huffman, J. A., DeCarlo, P. F., Ulbrich, I. M., Docherty, K. S., Sueper, D., Kimmel, J. R., Worsnop, D. R., Trimborn, A., Northway, M., Stone, E. A., Schauer, J. J., Volkamer, R. M., Fortner, E., de Foy, B., Wang, J., Laskin, A., Shutthanandan, V., Zheng, J., Zhang, R., Gaffney, J., Marley, N. A., Paredes-Miranda, G., Arnott, W. P., Molina, L. T., Sosa, G., and Jimenez, J. L.: Mexico City aerosol analysis during MILAGRO

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Identification of the main components of guazatine fungicide by gas chromatography and gas chromatography-mass spectrometry.

Identification of the main components of guazatine fungicide by gas chromatography and gas chromatography-mass spectrometry.

IDENTIFICATION OF THE MAIN COMPONENTS OF GUAZATINE FUNGICIDE BY GAS CHROMATOGRAPHY AND GAS CHROMATOGRAPHY-MASS SPECTROMETRY. Hexafluo- roacetylaceton derivatives of some synthesized components of the guazatine fungicide were pre- pared, and their separation and identification performed through gas chromatography and gas chromatography-mass spectrometry. The chromatogram obtained from hexafluoroacetylacetone derivative of the commercial guazatine presented 14 major peaks, and 9 of them were identified through both techniques mentioned above.
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