Selenium species in aqueous extracts of alfalfa sprouts by two-dimensional liquid chromatography coupled to inductively coupled plasma mass spectrometry and electrospray mass spectrometry detection

The complementary use of two different liquid chromatographic mechanisms coupled to inductively coupled plasma mass spectrometry (ICP-MS) for selenium (Se) specific detection has permitted the screening of the most abundant Se-containing fractions in selenized alfalfa sprouts (Medicago sativa). Aqueous extracts of the sprouts were fractionated first by size exclusion chromatography (SEC) using a Superdex Peptide column and a mobile phase containing an ammonium acetate buffer (pH 7). Further purification of the individual SEC Se-containing fractions was carried out using two different chromatographic systems: a Shodex Ashaipack column, with a mixed mechanism of size exclusion and ion exchange, and a conventional reversed phase C8 using ion-pairing reagents. In both cases, the columns were coupled to an inductively coupled plasma mass spectrometer equipped with an octapole reaction system for Se specific detection. This system allowed the on-line monitoring of the most abundant Se isotopes (78Se, 80Se) by reducing the possible polytomic interferences affecting these ions by adding hydrogen (2 mL min(-1)) to the octapole reaction cell. The results obtained by both separation mechanisms were highly comparable, revealing the presence of Se-methionine and Se-methyl selenocysteine. Both compounds were then confirmed by analyzing the corresponding fractions by electrospray quadrupole-time-of-flight (ESI-Q-TOF) mass spectrometry. Finally, an additional Se-containing species showing Se isotope distribution was detected at a molecular ion m/z 239 in the ESI-Q-TOF. The collision-induced dissociation of the m/z 239 and 237 ions (corresponding to 80Se and 78Se isotopes, respectively) revealed the possible presence as well of a derivative of the Se-2-propenyl selenocysteine.     

Simultaneous determination of alachlor, metolachlor, atrazine, and simazine in water and soil by isotope dilution gas chromatography/mass spectrometry

A multiresidue method was developed for the simultaneous determination of low parts per billion (ppb) concentrations of the herbicides alachlor, metolachlor, atrazine, and simazine in water and soil using isotope dilution gas chromatography/mass spectrometry (GC/MS). Known amounts of 15N,13C-alachlor and 2H5-atrazine were added to each sample as internal standards. The samples were then prepared by a solid phase extraction with no further cleanup. A high resolution GC/low resolution MS system with data acquisition in selected ion monitoring mode was used to quantitate herbicides in the extract. The limit of detection was 0.05 ppb for water and 0.5 ppb for soil. Accuracy greater than 80% and precision better than 4% was demonstrated with spiked samples.     

Pyrolysis-(gas chromatography/) mass spectrometry of agricultural soils and their humic fractions

Curie-point pyrolysis-gas chromatography/mass spectrometry and temperature-programmed in-source pyrolysis-field ionization mass spectrometry have been used for the chemical characterization of the organic material in agricultural soils with organic carbon contents between 1 and 1.5%. The results obtained from whole-soil samples, extractable humic substances and nonextractable humin by both techniques indicate for the Ap of a Gleysol thermal degradation products of carbohydrates, intact and/or biodegraded lignin, flavonoids, tannins and/or polyphenols, lipids, aliphatic polymers, and nitrogen-containing compounds. On a qualitative basis similar results have been obtained for the Ap of a Luvisol. The alkylbenzenes, alkylnaphthalenes, (di)alkylphenols, and alkyltoluenes identified are of special interest because these aryl-alkyl compounds demonstrate covalent linkages between aliphatic chains and aromatic subunits in soil organic matter. This type of linkage between individual subunits of the complex and polydisperse organic material enables the flexibility of rigid aromatic systems.     

Quantitative determination of polycyclic aromatic hydrocarbons in barbecued meat sausages by gas chromatography coupled to mass spectrometry

A method is described for the analysis of the 16 polycyclic aromatic hydrocarbons (PAHs) prioritized by the USA EPA in meat sausages grilled under common barbecue practices. Quantification was done by GC-MS using perdeuterated internal standards (IS). Validation was done by spiking the matrix at the 0.5 and 1.0 microg/kg levels. The average of expected values ranged from 60 to 134% (median 84%) at the 0.5 microg/kg level and from 69 to 121% (median 96%) at the 1.0 microg/kg level. The median of the limits of detection and quantification were 0.06 and 0.20 microg/kg, respectively, for a 4-g test portion. The carcinogenic PAHs were below the quantification limit in all products except one lamb sausage. Comparison of estimates when either 1, 5, or 16 perdeuterated PAHs were used as IS showed that the most accurate determination of PAHs required that each compound be quantified against its corresponding perdeuterated analogue.     

Determination of seven glycidyl esters in edible oils by gel permeation chromatography extraction and liquid chromatography coupled to mass spectrometry detection

A method based on a gel permeation chromatography (GPC) extraction procedure combined with an additional cleanup by solid-phase extraction (SPE) on silica gel and liquid chromatography-mass spectrometry (LC-MS) detection has been validated for the analysis of seven glycidyl esters (GEs) including glycidyl laurate, myristate, palmitate, stearate, oleate, linoleate, and linolenate in various edible oils. This method was conjointly developed and validated by two different laboratories, using two different detection systems, a LC time of flight MS (LC-ToF-MS) and a LC triple-quadrupole MS (LC-MS/MS). The extraction procedure allowed targeting low contamination levels due to a highly efficient matrix removal from the 400 mg oil sample loaded on the GPC column and is suitable for routine analysis as 24 samples can be extracted in an automated and reproducible way every 12 h. GPC extraction combined with SPE cleanup and LC-MS/MS detection leads to a limit of quantification in oil samples between 50 and 100 μg/kg depending on the type of glycidyl ester. Recoveries ranged from 68 to 111% (average = 93%). Quantification was performed by automated standard addition on extracts to compensate matrix effects artifacts. To control recoveries of each sample four isotopically labeled GEs ((13)C(3) or (13)C(4)) were included in the method.     

Quantitative high-throughput analysis of 16 (fluoro)quinolones in honey using automated extraction by turbulent flow chromatography coupled to liquid chromatography-tandem mass spectrometry

A method making use of turbulent flow chromatography automated online extraction with tandem mass spectrometry (MS/MS) was developed for the analysis of 4 quinolones and 12 fluoroquinolones in honey. The manual sample preparation was limited to a simple dilution of the honey test portion in water followed by a filtration. The extract was online purified on a large particle size extraction column where the sample matrix was washed away while the analytes were retained. Subsequently, the analytes were eluted from the extraction column onto an analytical column by means of an organic solvent prior to chromatographic separation and MS detection. Validation was performed at three fortification levels (i.e., 5, 20, and 50 microg/kg) in three different honeys (acacia, multiflower, and forest) using the single-point calibration procedure by means of either a 10 or 25 microg/kg calibrant. Good recovery (85-127%, median 101%) as well as within-day (2-18%, median 6%) and between-day (2-42%, median 9%) precision values was obtained whatever the level of fortification and the analyte surveyed. Due to the complexity of the honey matrix and the large variation of the MS/MS transition reaction signals, which were honey-dependent, the limit of quantification for all compounds was arbitrarily set at the lowest fortification level considered during the validation, e.g., 5 microg/kg. This method has been successfully applied in a minisurvey of 34 honeys, showing ciprofloxacin and norfloxacin as the main (fluoro)quinolone antibiotics administered to treat bacterial diseases of bees. Turbulent flow chromatography coupled to LC-MS/MS showed a strong potential as an alternative method compared to those making use of offline sample preparation, in terms of both increasing the analysis throughput and obtaining higher reproducibility linked to automation to ensure the absence of contaminants in honey samples.     

Simultaneous determination of four biogenic and three volatile amines in anchovy by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry

A new method has been developed and validated for the simultaneous determination of four biogenic (putrescine, cadaverine, histamine, and tyramine) and three volatile amines (trimethylamine, triethylamine, and tripropylamine) in anchovy. Separation and determination of the selected compounds were carried out by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS), using an electrospray ionization source (ESI) in positive ion mode. Chromatographic separation was carried out using an aqueous solution of formic acid (0.1%) and methanol as mobile phase in gradient mode. The method was validated, and mean recoveries were evaluated at three concentration levels (75, 150, and 250 μg/kg), ranging from 70 to 110% at the three levels assayed. Intra- and interday precision, expressed as relative standard deviation (RSD), were lower than 15% and 20%, respectively. Limits of quantitation (LOQs) were 25 μg/kg for all cases, except for that of TMA, which was set at 60 μg/kg. The developed procedure was applied to determine the target compounds in anchovy samples stored during 7 days at 4 °C, observing the increasing in the concentration of these compounds at longer storage time.     

Multiresidue assay for benzimidazole anthelmintics by liquid chromatography and confirmation by gas chromatography/selected-ion monitoring electron impact mass spectrometry

A multiresidue method utilizing all-disposable labware has been developed for 8 benzimidazole anthelmintics from ovine, bovine, and swine muscle and liver tissues. After an initial extraction with ethyl acetate and subsequent evaporation, a 3-component extraction using hexane, ethanol, and 0.2N HCl was used for final cleanup. Clean extracts were produced for separation and determination by reverse-phase liquid chromatography at 298 nm, using methanol and aqueous buffer as mobile phase. A synthesized internal standard, 2-(n-butylmercapto)benzimidazole, was used for quantitation of all drugs. Results are included along with statistical information verifying the performance of the method. Spiked control tissues and incurred drug tissues were used for an intralaboratory study with a concentration range of 50-1470 ppb. A series of standard curves at 0, 50, 100, and 200 ppb were analyzed. Overall recovery at the 100 ppb level averaged 92% (CV 8%) in liver tissues, across all 3 species and 88% (CV 5%) in muscle tissues across all 3 species. Results were confirmed by gas chromatography/mass spectrometry with acid hydrolysis of the remaining extract in 2N HCl followed by re-extraction of the amine and derivatization to the tert-butyldimethylsilyl derivative. The anthelmintics were identified by gas chromatography/selected ion monitoring electron-impact mass spectrometry. Ion ratio measurements were taken and compared to standard material. CVs averaged 10% or less for all drugs tested.     

Determination of flunixin in edible bovine tissues using liquid chromatography coupled with tandem mass spectrometry

An accurate, reliable, and reproducible assay was developed and validated to determine flunixin in bovine liver, kidney, muscle, and fat. The overall recovery and percent coefficient of variation (%CV) of twenty-eight determinations in each tissue for flunixin free acid were 85.9% (5.9% CV) for liver, 94.6% (9.9% CV) for kidney, 87.4% (4.7% CV) for muscle, and 87.6% (4.4% CV) for fat. The theoretical limit of detection was 0.1 microg/kg (ppb, ng/g) for liver and kidney, and 0.2 ppb for muscle and fat. The theoretical limit of quantitation was 0.3, 0.2, 0.6, and 0.4 ppb for liver, kidney, muscle, and fat, respectively. The validated lower limit of quantitation was 1 ppb for edible tissues with the upper limit of 400 ppb for liver and kidney, 100 ppb for fat, and 40 ppb for muscle. Accuracy, precision, linearity, specificity, ruggedness, and storage stability were demonstrated. Briefly, the method involves an initial acid hydrolysis, followed by pH adjustment ( approximately 9.5) and partitioning with ethyl acetate. A portion of the ethyl acetate extract was purified by solid-phase extraction using a strong cation exchange cartridge. The eluate was then evaporated to dryness, reconstituted, and analyzed using LC/MS/MS. The validated method is sensitive and specific for flunixin in edible bovine tissue.     

Multiresidue analysis of pesticides in soil by gas chromatography with nitrogen-phosphorus detection and gas chromatography mass spectrometry

A rapid multiresidue method for the simultaneous determination of 25 fungicides and insecticides in soil was developed. Soil samples are extracted by sonication with a water-acetonitrile mixture, and the pesticides are partitioned into dichloromethane. Final determination was made by gas chromatography (GC) with nitrogen-phosphorus detection (NPD). Confirmation analysis of pesticides was carried out by GC-MS in the selected ion monitoring (SIM) mode. The identification of compounds was based on retention time and on comparison of the primary and secondary ions. The average recovery by the GC-NPD method obtained for these compounds varied from 68.5% to 112.1% with a relative standard deviation between 1.8% and 6.2%. The GC-NPD method presents good linearity over the range assayed 50-2000 microg/L, and the detection limit for the pesticides studied varied from 0.1 to 10.4 microg/kg. The proposed method was used to determine pesticide levels in soil samples from experimental greenhouse pepper cultivation.     

Determination of triazine and chloroacetanilide herbicides in soils by microwave-assisted extraction (MAE) coupled to gas chromatographic analysis with either GC-NPD or GC-MS

A simple and rapid method based on microwave-assisted extraction (MAE) coupled to gas chromatographic analysis was developed for the analysis of triazine (atrazine, cyanazine, metribuzine, simazine and deethylatrazine, and deisopropylatrazine) and chloroacetanilide (acetochlor, alachlor, and metolachlor) herbicide residues in soils. Soil samples are processed by MAE for 5 min at 80 degrees C in the presence of acetonitrile (20 mL/sample). Mean recovery values of most solutes are >80% in the 10 to 500 microg/kg fortification range with respective RSDs (relative standard deviations) < 20%. The limits of quantification (LOQ) and limits of detection (LOD) are 10 and 1 to 5 microg/kg, respectively. The method was validated with two types of soils containing 1.5 and 3.0% organic matter content, respectively; no statistically significant differences were found between solute recovery values from the two types of soils. The solute mean recovery values from freshly spiked (24 h aging) and spiked samples stored refrigerated for one week before processed were also not statistically different. Residue levels determined in field weathered soils were higher when soils were processed by MAE than with a comparison method based on flask-shaking of soil suspensions overnight. Extracts were analyzed by a gas chromatographic system equipped either with a thermionic (GC-NPD) or a mass spectrometric detector (GC-MS).     

Separation of flavanone-7-O-glycoside diastereomers and analysis in citrus juices by multidimensional liquid chromatography coupled with mass spectrometry

The major flavanone-7-O-glycoside constituents in citrus fruit juices (naringin, hesperidin, neohesperidin, narirutin, and eriocitrin) were separated as diastereomers by multidimensional liquid chromatography. The method consisted of coupling two HPLC columns: a reversed-phase (RP(18)) column was used for the separation of flavanone glycosides, which were, then, individually switched into a carboxymethylated beta-cyclodextrin (beta-CD)-based column and resolved as the corresponding stereoisomers. The method was used for the full analysis of flavanone glycosides in fresh hand-squeezed and commercial fruit juices by combining the quantitative estimation with the diastereomeric analysis. Quantitative data were in general consistent with previously reported data in this field. CC-LC isomer analysis was carried out by coupling the beta-CD column with a mass spectrometer operated with negative ion electrospray ionization (ESI-MS). The results showed that hesperidin was present in orange juices almost exclusively as the 2S isomer, whereas narirutin had mainly the 2R configuration. In grapefruit juices (2S)-naringin prevailed with the respect to the 2R isomer, whereas the opposite was true for narirutin. Lemon juices contained eriocitrin stereoisomers in equal amount (50% each), but hesperidin was almost exclusively found as the 2S isomer. Significant differences of the diastereomeric ratios were observed between freshly squeezed juices and juices from commercial sources.     

Determination of pyrantel in swine liver by flame ionization gas chromatography and confirmation by gas chromatography/mass spectrometry

During an evaluation of the gas chromatography/mass spectrometry (GC/MS) confirmatory procedure of Lynch and Bartolucci for pyrantel residues in swine tissues, we developed a GC flame ionization method for quantitating pyrantel residues in extracts of swine liver. The method was subjected to trial principally in the laboratories of Biospherics, Inc., using control liver, fortified control liver, and incurred liver tissue samples. Although the method does not meet all of the current Food and Drug Administration criteria, it compares favorably to the official determinative method. Portions of the same extract can be used for quantitation and for GC/MS confirmation, true recoveries appear to be slightly higher, and an internal standard is not required. The precision of this method equals or exceeds that of the official determinative method.     

Analysis of Flavan-3-ols and procyanidins in food samples by reversed phase high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (RP-HPLC-ESI-MS/MS)

Concentrations of the main dimeric and trimeric procyanidins (PC) and their monomeric constitutive units catechin (CT) and epicatechin (EC) were determined in food samples by using reversed phase high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (RP-HPLC-ESI-MS/MS). In a first step, 12 PCs (PC B1, B2, B3, B4, B5, B6, B7, B8, C1, C2, and A2 and cinnamtannin B1), of which most are not commercially available, were isolated from plant materials or synthesized and purified by a combination of column chromatographic separation techniques with different stationary phases. These PCs in combination with CT and EC were used as standard substances for identification and quantification during the following screening of food samples by RP-HPLC-ESI-MS/MS analysis. The main focus of the newly developed RP-HPLC-ESI-MS/MS method is the compensation of matrix effects by using the echo-peak technique simulating internal standard injection. The suitability of this new method was demonstrated by the determination of recovery rates being 90% or higher. Use of this method allowed the determination of patterns and concentrations of PCs in 55 food samples.     

Development of analyses by high-performance liquid chromatography and liquid chromatography/tandem mass spectrometry of bilberry (Vaccinium myrtilus) anthocyanins in human plasma and urine

Anthocyanins are potent antioxidants that may possess chronic disease preventive properties. Here, rapid, reliable, and reproducible solid-phase extraction, high-performance liquid chromatography (HPLC), and mass spectrometry techniques are described for the isolation, separation, and identification of anthocyanins in human plasma and urine. Recoveries of cyanidin-3-glucoside (C3G) were 91% from water, 71% from plasma, and 81% from urine. Intra- and interday variations for C3G extraction were 9 and 9.1% in plasma and 7.1 and 9.1% in urine and were less than 15% for all anthocyanins from a standardized bilberry extract (mirtoselect). Analysis of mirtoselect by HPLC with UV detection produced spectra with 15 peaks compatible with anthocyanin components found in mirtoselect within a total run time of 15 min. Chromatographic analysis of human urine obtained after an oral dose of mirtoselect yielded 19 anthocyanin peaks. Mass spectrometric analysis employing multiple reaction monitoring suggests the presence of unchanged anthocyanins and anthocyanidin glucuronide metabolites.     

Determination of nicarbazin in chicken tissues by liquid chromatography and confirmation of identity by thermospray liquid chromatography/mass spectrometry

A liquid chromatographic method is described for the quantitative measurement of nicarbazin in chicken liver, fat, muscle, and skin tissues. The 4,4'-dinitrocarbanilide (DNC) portion of nicarbazin is extracted from tissues with ethyl acetate. After filtration and evaporation, the extract is purified by liquid-liquid partitioning with acetonitrile-hexane and alumina cartridge chromatography. DNC is separated and measured by reverse-phase liquid chromatography (RP-LC) with an octadecylsilyl (ODS) column and a UV detector set at 340 nm. The overall average recovery of DNC added to tissues was 83.4 +/- 3.1%. The lowest level validated in tissues by this procedure was 0.10 ppm. The limit of detection was estimated to be 0.020 ppm. This method provides a sensitive, selective, rapid, and reproducible alternative to existing purification, separation, and detection techniques, such as differential pulse polarography and colorimetry, for determination of nicarbazin in chicken tissues. Identity of DNC is confirmed by subjecting the purified extracts to thermospray-LC/mass spectrometric analysis using negative-ion detection and selected ion monitoring. Three structural-indicating ions at m/z 302, 272, and 164 are monitored in the thermospray-mass spectrum which are characteristic of the DNC molecule.     

Application of gas chromatography coupled to triple quadrupole mass spectrometry for the multiresidue analysis of pesticides in olive oil

A new multiresidue method has been developed and validated for the simultaneous determination of 100 pesticide residues in olive oil. The determination of pesticide residues was carried out in only 19 min by gas chromatography coupled to tandem mass spectrometry using a triple quadrupole mass analyzer. The mass spectrometer was operated in electron ionization and the selection reaction monitoring mode was used, acquiring two or three fragmentation reactions per compound. Two extraction processes were studied, and an evaluation of the stability and sensitivity of the chromatographic system has been performed for the tested extraction procedures. The final proposed methodology was based on a liquid-liquid partition with an n-hexane/acetonitrile mixture followed by a gel permeation chromatography cleanup step. An adequate lineal relation was obtained in the studied concentration range (10-200 microg kg (-1)); the recovery values were in the range 70-110% for the two levels of concentration studied: 12 and 50 microg kg (-1). Precision values, expressed as relative standard deviation, were lower than 18% at the aforementioned spiking levels; detection limits, confirmation limits, and quantitation limits were below or equal to 1.9, 2.6, and 3.6 microg kg (-1), respectively. The developed methodology was applied to the analysis of pesticide residues in real samples of olive oil from the south of Spain.     

Identification of free amino acids in peat by gas chromatography and mass spectrometry

The qualitative and quantitative composition of free amino acids in a typical Finnish peat bog at various depths down to 5.3 m below the surface was studied using capillary gas chromatography and mass spectrometry. Sixteen amino acids were identified at each depth: α-alanine, β-alanine, glycine, valine, leucine, proline, isoleucine, serine, threonine, glutamic acid, aspartic acid, phenylalanine, tyrosine, γ-aminobutyric acid, ornithine and lysine. Their amounts decreased markedly at a depth of 40–100 cm. The total amount of amino acids varied between 0.6 and 5.6 g kg^?1 dry matter (i.e. 0.06–0.56%) depending on the depth. The proportion of neutral amino acids was greatest at all depths studied, except at the surface layer where it ranged between 41 and 72% by mass. The acidic amino acids decreased with depth from 56 to 23% of the total. The proportion of aromatic amino acids was very small, 3.2–5.5% by mass. In samples from aerobic conditions, where the microbial production of free amino acids was the greatest, α-ala, gly, glu and asp were most abundant. In peat from anaerobic conditions, where the microbiological activity was low, the proportion of the most chemically stable amino acid was exceptionally high. This may have been because glycine was a degradation product of other amino acids or peptides. Peat type and degree of decomposition had a strong influence on the total amount of free amino acids and their qualitative composition.     

Analysis of herbicides in olive oil by liquid chromatography time-of-flight mass spectrometry

The application of liquid chromatography time-of-flight mass spectrometry (LC/TOF-MS) for the identification and quantitation of four herbicides (simazine, atrazine, diuron, and terbuthylazine) in olive oil samples is reported here. The method includes a sample treatment step based on a preliminary liquid-liquid extraction followed by matrix solid-phase dispersion (MSPD) using aminopropyl as a sorbent material. A final cleanup step is performed with florisil using acetonitrile as an eluting solvent. The identification by LC/TOF-MS is accomplished with the accurate mass (and the subsequent generated empirical formula) of the protonated molecules [M + H]+, along with the accurate mass of the main fragment ion and the characteristic chlorine isotope cluster present in all of them. Accurate mass measurements are highly useful in this type of complex sample analyses since they allow us to achieve a high degree of specificity, often needed when other interferents are present in the matrix. The mass accuracy typically obtained is routinely better than 2 ppm. The sensitivity, linearity, precision, mass accuracy, and matrix effects are studied as well, illustrating the potential of this technique for routine quantitative analyses of herbicides in olive oil. Limits of detection (LODs) range from 1 to 5 microg/kg, which are far below the required maximum residue level (MRL) of 100 microg/kg for these herbicides in olive oil.     

Quantitative ester analysis in cachaca and distilled spirits by gas chromatography-mass spectrometry (GC-MS)

An analytical procedure for the separation and quantification of ethyl acetate, ethyl butyrate, ethyl hexanoate, ethyl lactate, ethyl octanoate, ethyl nonanoate, ethyl decanoate, isoamyl octanoate, and ethyl laurate in cachaca, rum, and whisky by direct injection gas chromatography-mass spectrometry was developed. The analytical method is simple, selective, and appropriated for the determination of esters in distilled spirits. The limit of detection ranged from 29 (ethyl hexanoate) to 530 (ethyl acetate) microg L(-1), whereas the standard deviation for repeatability was between 0.774% (ethyl hexanoate) and 5.05% (isoamyl octanoate). Relative standard deviation values for accuracy vary from 90.3 to 98.5% for ethyl butyrate and ethyl acetate, respectively. Ethyl acetate was shown to be the major ester in cachaca (median content of 22.6 mg 100 mL(-1) anhydrous alcohol), followed by ethyl lactate (median content of 8.32 mg 100 mL(-1) anhydrous alcohol). Cachaca produced in copper and hybrid alembic present a higher content of ethyl acetate and ethyl lactate than those produced in a stainless-steel column, whereas cachaca produced by distillation in a stainless-steel column present a higher content of ethyl octanoate, ethyl decanoate, and ethyl laurate. As expected, ethyl acetate is the major ester in whiskey and rum, followed by ethyl lactate for samples of rum. Nevertheless, whiskey samples exhibit ethyl lactate at contents lower or at the same order of magnitude of the fatty esters.