Combination of sugar analysis and stable isotope ratio mass spectrometry to detect the use of artificial sugars in royal jelly production

The effects of feeding bees artificial sugars and/or proteins on the sugar compositions and ¹³C isotopic measurements of royal jellies (RJs) were evaluated. The sugars fed to the bees were two C4 sugars (cane sugar and maize hydrolysate), two C3 sugars (sugar beet, cereal starch hydrolysate), and honey. The proteins fed to them were pollen, soybean, and yeast powder proteins. To evaluate the influence of the sugar and/or protein feeding over time, samples were collected during six consecutive harvests. ¹³C isotopic ratio measurements of natural RJs gave values of around −25 ‰, which were also seen for RJs obtained when the bees were fed honey or C3 sugars. However, the RJs obtained when the bees were fed cane sugar or corn hydrolysate (regardless of whether they were also fed proteins) gave values of up to −17 ‰. Sugar content analysis revealed that the composition of maltose, maltotriose, sucrose, and erlose varied significantly over time in accordance with the composition of the syrup fed to the bees. When corn and cereal starch hydrolysates were fed to the bees, the maltose and maltotriose contents of the RJs increased up to 5.0 and 1.3 %, respectively, compared to the levels seen in authentic samples (i.e., samples obtained when the bees were fed natural food: honey and pollen) that were inferior to 0.2% and not detected, respectively. The sucrose and erlose contents of natural RJs were around 0.2 %, whereas those in RJs obtained when the bees were fed cane or beet sugar were as much as 4.0 and 1.3 %, respectively. The combination of sugar analysis and ¹³C isotopic ratio measurements represents a very efficient analytical methodology for detecting (from early harvests onward) the use of C4 and C3 artificial sugars in the production of RJ.     

Characterization of ganoderma spore lipid by stable carbon isotope analysis: implications for authentication

The ratios of stable carbon isotopes (¹³C/¹²C) of ganoderma fruiting body, ganoderma spore, ganoderma spore lipid (GSL) and individual fatty acids in GSL were determined by gas chromatography–stable isotope ratio mass spectrometry and elemental analysis–stable isotope ratio mass spectrometry. These values fall into a range from −26.9 to −23.3‰, suggesting that the cut log as the Ganoderma-cultivated substrate in Fujian, China, may belong to C3 plants. Eighteen fatty acids were identified and their abundances measured by gas chromatography–mass spectrometry in the six GSL samples with C_16:0, C_18:0, C_18:1 and C_18:2 as major constituents, and C_16:1 is evidently enriched compared with the other edible vegetable oils. On the basis of the compositions of fatty acids and stable carbon isotopes in GSL, we have developed a novel method to detect the adulteration of GSL products with cheaper edible vegetable oils. An example of ideal blending between GSL and C4 or C3 vegetable oil is further provided to expound the discrimination procedures and corresponding sensitive indicators. Simultaneously, the carbon isotope fractionation in the biosynthesis of individual fatty acids was observed, revealing that the formation of C_18:0 from C_16:0 in ganodema spores had no conspicuous ¹³C enrichment of +0.4‰ for Ganoderma sinensis spore and +0.1‰ for G. lucidum spore; the desaturation of C_18:0 to C_18:1 resulted in a distinct ¹³C depletion of −1.4‰ for G. sinensis spore and −0.9‰ for G. lucidum spore; and the next desaturation from C_18:1 to C_18:2 displayed no evident ¹³C fractionation of −0.1‰ for G. sinensis spore and −0.2‰ for G. lucidum spore. Figure Ganoderma lucidum has been widely used in traditional Chinese medicines. Ganoderma spore lipid (GSL) extracted from the spores of G. lucidum has been approved as a health food supplement. However, because of rarity, GSL has become a target for adulteration with cheaper vegetable oils.     

Evaluation of vinasses from sugarcane molasses distillation as a new source of sugarcane wax

Molasses, a by-product of sugar manufacturing, are the most common raw material for rum manufacturing. During the fermentation and distillation process, vinasses are produced in large quantities and disposed in landfills. In this study, they were evaluated as a new source of sugarcane wax. The chemical composition of the wax was studied by GC-Mass spectroscopy. A series of n-alkanes (C₂₃–C₃₃) and ethyl and methyl esters of fatty acids (palmitate and oleate are the predominant), of phytosterols (stigmasterol, β-sitosterol, campesterol), free fatty acids (C_12:0–C_36:0), and triglycerides constitute the main components. In addition, 2-ketones (C₂₇–C₃₃), aldehydes (C₂₈, C₃₂, C₃₄), ketosteroids (derivatives of stigmasterol, β-sitosterol, and campesterol), and fatty alcohol acetates (alcohol moiety: C₂₈, C₃₀, C₃₂) were found as minor products. Published in Khimiya Prirodnykh Soedinenii, No. 5, pp. 448–450, September-October, 2008. Original article submitted March 19, 2007.     

Unusual Fragmentation of β-Linked Peptides by ExD Tandem Mass Spectrometry

Ion-electron reaction based fragmentation methods (ExD) in tandem mass spectrometry (MS), such as electron capture dissociation (ECD) and electron transfer dissociation (ETD) represent a powerful tool for biological analysis. ExD methods have been used to differentiate the presence of the isoaspartate (isoAsp) from the aspartate (Asp) in peptides and proteins. IsoAsp is a β₃-type amino acid that has an additional methylene group in the backbone, forming a C_α–C_β bond within the polypeptide chain. Cleavage of this bond provides specific fragments that allow differentiation of the isomers. The presence of a C_α–C_β bond within the backbone is unique to β-amino acids, suggesting a similar application of ExD toward the analysis of peptides containing other β-type amino acids. In the current study, ECD and ETD analysis of several β-amino acid containing peptides was performed. It was found that N–C_β and C_α–C_β bond cleavages were rare, providing few c and z type fragments, which was attributed to the instability of the C_β radical. Instead, the electron capture resulted primarily in the formation of a and y fragments, representing an alternative fragmentation pathway, likely initiated by the electron capture at a backbone amide nitrogen protonation site within the β amino acid residues.     

Reagent peak-free liquid chromatography–fluorescence analysis of carboxylic acids using a fluorous scavenging–derivatization method

We developed a fluorous scavenging–derivatization method for reagent peak-free liquid chromatography (LC)–fluorescence analysis of carboxylic acids. In this method, carboxylic acids were fluorescently derivatized with 1-pyrenemethylamine in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 1-hydroxy-1H-benzotriazole. Residual excess unreacted reagent was tagged with 2-(perfluorooctyl)ethyl isocyanate and could be selectively removed by microfluorous solid-phase extraction before LC analysis. With use of this method, eight fluorescent derivatives of linear aliphatic carboxylic acids (C₁–C₈) can be separated within 30 min by reversed-phase LC with gradient elution. In the chromatogram obtained, the fluorous-tagged unreacted reagent peak is greatly decreased after microfluorous solid-phase extraction and does not interfere with the quantification of each acid. With use of microfluorous solid-phase extraction with 80% (v/v) aqueous methanol elution, over 99.9% of the unreacted fluorescent reagent was removed. The detection limits (signal-to-noise ratio of 3) for the carboxylic acids examined are 2.3–8.0 fmol per 10-μL injection. We also applied this method successfully to the analysis of highly polar carboxylic acids such as α-keto acids and tricarboxylic acid cycle metabolites.     

Kinetics of β-picoline oxidation to nicotinic acid over vanadia-titania catalyst. 3. The oxidation of nicotinic acid

The oxidation of nicotinic acid (NA) over binary vanadia-titania catalysts with different contents of residual sulfate ions (0.2 and 2.8 wt. %) was studied at 250–300°C in the feed reaction mixture of the composition NA: O₂: H₂O = 0.01–0.17: 5–20: 0–20 (vol. %), with nitrogen as a balance. The kinetic parameters of the process were determined. It was shown that even a ten-fold increase in the content of residual sulfate ions in the samples has no significant effect on the kinetics of the NA oxidation.     

Comparison of SO2 and H2SO4 impregnation of softwood prior to steam pretreatment on ethanol production

The pretreatment of softwood with sulfuric acid impregnation in the production of ethanol, based on enzymatic hydrolysis, has been investigated. The parameters investigated were: H₂SO₄ concentration (0.5 – 4.4% w/w liquid), temperature (180 – 240°C), and residence time (1-20 minutes). The combined severity (log Ro-pH) was used to combine the parameters into a single reaction ordinate. The highest yields of fermentable sugars, i.e., glucose and mannose, were obtained at a combined severity of 3. At this severity, however, the fermentability declined and the ethanol yield decreased. In a comparison with previous results, SO₂ impregnation was found to be preferable, since it resulted in approximately the same sugar yields, but better fermentability.     

Quantitative study of hydration of C<Subscript>3</Subscript>S and C<Subscript>2</Subscript>S by thermal analysis

This research is part of a European project (namely, CODICE project), main objective of which is modelling, at a multi-scale, the evolution of the mechanical performance of non-degraded and degraded cementitious matrices. For that, a series of experiments were planned with pure synthetic tri-calcium silicate (C₃S) and bi-calcium silicate (C₂S) (main components of the Portland cement clinker) to obtain different calcium–silicate–hydrate (C–S–H) gel structures during their hydration. The characterization of those C–S–H gels and matrices will provide experimental parameters for the validation of the multi-scale modelling scheme proposed. In this article, a quantitative method, based on thermal analyses, has been used for the determination of the chemical composition of the C–S–H gel together with the degree of hydration and quantitative evolution of all the components of the pastes. Besides, the microstructure and type of silicate tetrahedron and mean chain length (MCL) were studied by scanning electron microscopy (SEM) and ²⁹Si magic-angle-spinning (MAS) NMR, respectively. The main results showed that the chemical compositions for the C–S–H gels have a CaO/SiO₂ M ratio almost constant of 1.7 for both C₃S and C₂S compounds. Small differences were found in the gel water content: the H₂O/SiO₂ M ratio ranged from 2.9 ± 0.2 to 2.6 ± 0.2 for the C₃S (decrease) and from 2.4 ± 0.2 to 3.2 ± 0.2 for the C₂S (increase). The MCL values of the C–S–H gels, determined from ²⁹Si MAS NMR, were 3.5 and 4 silicate tetrahedron, for the hydrated C₃S and C₂S, respectively, remaining almost constant at all hydration periods.     

A thorough study of the surface wax of apple fruits

The composition of the surface waxes of three apple ( Malus domestica L.) cultivars ("Florina", "Golden B" and "Ozark Gold") has been studied by means of spectroscopic and GC–MS analysis of the class-fractionated mixture of components. Odd n -alkanes, mainly C₂₇ and C₂₉ molecules, are prevalent in the saturated fraction. Small concentrations of alkenes were also found; the C_28:1 component is strongly (72%) in excess over the other 1-alkenes. Straight-chain esters (mainly of palmitic acid) of saturated primary alcohols (C₁₈–C₃₀) were also detected; whereas the acyl moiety is made up essentially of an even number of carbons, the alcohol counterpart does not exhibit this characteristic. Aldehydes are present (C₂₀–C₃₀) with the homologue patterns C₂₆–C₃₀ most strongly represented. Straight-chain free secondary alcohols characterize the waxes of "Florina" and "Ozark Gold"; the hydroxy function is located far from the extremity of the carbon framework. Outstanding is the presence of three alcohols with 29 carbon centres. These alcohols are accompanied by free straight-chain primary alcohols, mainly with even-numbered carbon chains in the range C₂₆–C₃₀. Free fatty acids are present; all of have a framework of even-numbered carbon chains mainly in the range C₁₆–C₂₀. C_18:1 (oleic acid) is well represented.     

Determination of Phenolic Acids in Herba Epilobi by ITP–CE in the Column-Coupling Configuration

The combination of capillary isotachophoresis (ITP) and capillary zone electrophoresis (CZE) in the column-coupling configuration has been optimized in a mode in which the background electrolyte employed in the CZE step was different from the leading and terminating electrolytes of the ITP step. The optimum composition of the electrolyte system was 0.01 M HCl, 0.02 M IMI, 0.2% HEC, pH 7.2 (leading electrolyte), 0.01 M HEPES, pH 8.2 (terminating electrolyte), and 25 mM MES, 50 mM TRIS, 30 mM boric acid, 0.2% HEC, pH 8.3 (background electrolyte). All solutions contained 20% methanol. The timing of the transfer of isotachophoretically stacked analyte zones into the CZE column was also optimized. An ITP–CZE method with UV detection at 270 nm was developed for separation of nine phenolic acids (protocatechuic, syringic, vanillic, cinnamic, ferulic, caffeic, ρ-coumaric, chlorogenic, and gentisic acids) in a model mixture and used for assay of some of these acids in a methanolic extract of herba epilobi. Application of ITP–CZE resulted in 100-fold better sensitivity than conventional CZE; limits of detection ranged between 10 and 60 ng mL⁻¹. When MES–TRIS–borate-based buffer, pH 8.3, was used in the CZE separation step the linearity of the ITP–CZE response was satisfactory (correlation coefficients were from 0.9937 to 0.9777). Repeatability was also satisfactory (RSD values ranged between 0.77% and 1.28% for migration times and between 1.65% and 13.69% for peak area). Revised: 23 March and 27 April 2006     

Determination of sulfonylurea herbicides in soil extracts by solid-phase extraction and capillary zone electrophoresis

Summary Sulfonylurea herbicides in soil extracts were concentrated using off-line solid-phase extraction (SPE), and determined by capillary zone electrophoresis (CZE) and UV detection. The method involves extraction of soils with 0.1 M NaHCO₃ solution and subsequent preconcentration by using C₁₈ cartridges prior to separation of the pesticide using CZE. The results show that a C₁₈ cartridge is suitable for the purification of sulfonylurea herbicides in soil extracts with the recoveries ranging from 65–103%. The separation conditions affecting the resolution and detection sensitivity was systematically investigated. The sulfonylureas were resolved well using 30 mM sodium acetate (NaAc)/acetic acid (HAc)+10% acetonitrile (ACN) buffer at pH 4.80. The calibration plots for the test solutes in the concentration of 0.2–50 mg L⁻¹ were linear with detection limits in the range of 0.05–0.10 mgL⁻¹. The proposed method has been successfully demonstrated for the determination of sulfonylurea herbicides in soil samples.     

Combined steam pretreatment and enzymatic hydrolysis of starch-free wheat fibers

Steam treatment of an industrial process stream, denoted starch-free wheat fiber, was investigated to improve the formation of monomeric sugars in subsequent enzymatic hydrolysis for further bioconversion into ethanol. The solid fraction in the process stream, derived from a combined starch and ethanol factory, was rich in arabinose (21.1%), xylose (30.1%), and glucose (18.6%), in the form of polysaccharides. Various conditions of steam pretreatment (170–220°C for 5–30 min) were evaluated, and their effect was assessed by enzymatic hydrolysis with 2 g of Celluclast + Ultraflo mixture/ 100 g of starch-free fiber (SFF) slurry at 5% dry matter (DM). The highest overall sugar yield for the combined steam pretreatment and enzymatic hydrolysis, 52g/100 g of DM of SFF, corresponding to 74% of the theoretical, was achieved with pretreatment at 190°C for 10 min followed by enzymatic hydrolysis.     

Optimization of SO2-catalyzed steam pretreatment of corn fiber for ethanol production

A batch reactor was employed to steam explode corn fiber at various degrees of severity to evaluate the potential of using this feedstock as part of an enzymatically mediated cellulose-to-ethanol process. Severity was controlled by altering temperature (150–230°C), residence time (1–9 min), and SO₂ concentration (0–6% [w/w] dry matter). The effects of varying the different parameters were assessed by response surface modeling. The results indicated that maximum sugar yields (hemicellulose-derived water soluble, and cellulose-derived following enzymatic hydrolysis) were recovered from corn fiber pretreated at 190°C for 5 minutes after exposure to 3% SO₂. Sequential SO₂-catalyzed steam explosion and enzymatic hydrolysis resulted in a conversion efficiency of 81% of the combined original hemicellulose and cellulose in the corn fiber to monomeric sugars. An additional posthydrolysis step performed on water soluble hemicellulose stream increased the concentration of sugars available for fermentation by 10%, resulting in the high conversion efficiency of 91%. Saccharomyces cerevisiae was able to ferment the resultant corn fiber hydrolysates, perhydrolysate, and liquid fraction from the posthydrolysis steps to 89, 94, and 85% of theoretical ethanol conversion, respectively. It was apparent that all of the parameters investigated during the steam explosion pretreatment had a significant effect on sugar recovery, inhibitory formation, enzymatic conversion efficiency, and fermentation capacity of the yeast.     

Oxidation of brown coal of Angren deposit with a mixture of nitric and sulfuric acids

Oxidation of brown coal of Angren deposits by a mixture of nitric and sulfuric acids was studied in respect of dependence on the concentration of nitric acid (5–30%), concentration of sulfuric acid in nitric acid solution (2.5–20%), and temperature (40–80°C) at the process duration 2 h and the ratio of coal: HNO₃ = 1: 2. Optimal conditions of the process in terms of maximum yield of humic acids and the minimum loss of nitrogen oxides were found.     

Evaluation of carob pod as a substrate for pullulan production byAureobasidium pullulans

The production of extracellular polysaccharides from carob pod extract by Aureobasidium pullulans in batch fermentation was investigated. Optimum conditions for polysaccharide productivity, polysaccharide yield, and fermentation efficiency were: initial sugar concentration of 25 g/L, initial pH 6.5, and temperature 25–30°C. A maximum polysaccharide concentration (6.5 g/L), polysaccharide productivity (2.16 g/L/d), total biomass concentration (6.3 g/L), and polysaccharide yield (30%) were obtained with inoculum at 10% (v/v), initial sugars in carob pod extract of 25 g/L, pH 6.5, and 25°C. The highest values of pullulan proportion (70% of total polysaccharides) and fermentation efficiency (89%) were assumed at initial sugar concentration of 25 g/L, pH 6.5 and 30°C. Structural characterization of purified pullulan samples by monosaccharide and methylation analyses, 13C-NMR, and pullulanase digestion combined with size-exclusion chromatography revealed the presence of mainly α-(l → 4) (68%) and α-(l → 6) (31%) glucosidic linkages; however, small amounts (<1%) of triply linked (1, 3, 4-and 1, 4, 6-Glc) glucose residues were detected. The molecularsize distribution and intrinsic viscosity of pullulan derived from culture grown at pH 4.5 (30°C) showed a higher molecular weight than its counterpart obtained at pH 6.5 (30°C).     

An improved derivatization method for sensitive determination of fatty acids by high-performance liquid chromatography using 9-(2-hydroxylethyl)-carbazole as derivatization reagent with fluorescence detection

Summary Tagging techniques with reagents used for fluorescent detection for short and long-chain fatty acids using high-performance liquid chromatography are evaluated in terms of the tagging reactions, handing, flexibility, stability of the reagents. Emphasis is given to the applications of the tagging techniques to relatively high molecular mass fatty acids. The fatty acids or carboxylic compounds were derivatized to their corresponding esters with 9-(2-hydroxy ethyl)-carbazole (HEC) in acetonitrile at 60°C with N, N′-carbonyldiimidazole (CDI) as a coupling agent in the presence of 4-dimethylaminopyridine (DMAP). A mixture of esters of C₁−C₂₀ fatty acids was completely separated with 45 min using gradient elution on a reversed-phase C₁₈ column. The maximum fluorescence emission for the derivatized fatty acids is at 365 nm (λ_ex 293 nm). Studies on derivatization conditions indicated that fatty acids react rapidly and smoothly with HEC in the presence of CDI and DMAP in acetonitrile to give the corresponding sensitively fluorescent derivatives. The application of this method to the analysis of long chain fatty acids in plasma is also investigated. The LC separation shows good selectivity and reproducibility for fatty acids derivatives. The relative standard deviations (n=6) for each fatty acid derivative are <5.0%. The detection limits are at 38–57 fmol levels for C₁₄−C₂₀ fatty acids and lower levels for <C₁₄ fatty acids.     

Simultaneous determination of azelaic and benzoic acids in topical preparations by liquid chromatography

Summary An isocratic, reversed-phase liquid chromatographic (LC) method has been developed for the simultaneous determination of azelaic and benzoic acids in pharmaceutical creams. The compounds were separated on a C₁₈ column (4 μm particles); the mobile phase was methanolwater, 40∶60, containing 10mm ammonium acetate and with the pH adjusted to 5.0. Detection was performed at 220 nm. The method was validated for accuracy, linearity, precision, and selectivity. Recoveries at levels corresponding to 80% to 120% of the declared content of the creams ranged from 99.5 to 101.8% and from 100.4 to 102.1% for azelaic and benzoic acids, respectively. The calibration graphs were linear in the ranges 20–1400 μg mL⁻¹ for azelaic acid (correlation coefficient,r ₁>0.99999), and 0.1–7.0 μg mL⁻¹ for benzoic acid (r>0.99998).     

The stabilization of titanium dioxide in dry benzene by n-aliphatic carboxylic acids

Summary The colloidal stability of rutile, of primary particle radius 25 ?, in solutions ofn-aliphatic carboxylic acids in benzene has been examined under rigorously dry conditions. Very stable suspensions were obtained for acid chain lengths of 12 to 18 carbons and surface fractional coverages of 0.4. A rather less stable suspension was given by acetic acid. The C_{4, 6, 8, and 10} acids gave poor stability. The suspensions generally, and that for lauric acid in particular, appeared to consist mainly of particles whose radius was of the order of 0.08Μ. It has been argued that these particles were probably loosely packed aggregates of primary particles and that their stability was conferred by the C_12–18 molecules by an “entropic” repulsion produced when the hydrocarbon chains on opposing particle surfaces tended to interpenetrate. The stability in the acetic, and to a lesser extent, butyric acid systems has been attributed tentatively to the existence of some electrostatic repulsion.

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Zusammenfassung Die Stabilit?t von Rutil von einem Radius von 25 ? der Prim?rteilchen in kolloiden L?sungen von Benzol mitn-aliphatischen Carboxyls?uren wurde unter extremem Feuchtigkeitsausschlu\ geprüft. Sehr stabile Suspensionen lagen für Kettenl?ngen von 12–18 Kohlenstoff-Atomen und einer Oberfl?chenbedeckung von 0,4 vor. Ziemliche Stabilit?t ergab sich für Essigs?ure als Zusatz. Sehr gro\e Instabilit?t zeigte sich für Kettenl?ngen von 4–10. Die Suspensionen im allgemeinen und die für Lauryls?ure im besonderen scheinen haupts?chlich aus Partikeln von einem Radius der Gr?\enordnung von 0.08Μ zu bestehen. Es wird vermutet, da\ diese Teilchen wahrscheinlich locker gepackte Aggregate von Prim?rpartikeln sind und da ihre Stabilit?t wahrscheinlich für die C_12–18-Moleküle durch eine entropische Absto\ung hervorgerufen wird, wenn sich die Kohlenwasserstoffketten senkrecht der Oberfl?chen der verschiedenen Partikel zu durchdringen beginnen. Die Stabilit?t in dem Essigs?ure- und in einem geringeren Ausma\ in dem Butters?uresystem — wird der Existenz einer gewissen elektrostatischen Abschirmung zugeschrieben.

     

Gas chromatographic analysis of C2−C16 dicarboxylic acids esterified in aqueous solutions as n-propyl esters

Summary C₂−C₁₆ dicarboxylic acids were esterified in aqueous solution in the presence of sulfuric acid. Esterification in water/n-propanol mixtures with mole ratios between 0.03 and 2.21 can be utilized for the quantitative determination of dicarboxylic acids by gas chromatography. The presence of water does not interfere at water/n-propanol mole ratios below 0.45. For mole ratios above 0.45 anhydrous sodium sulfate has been used for binding the water. The mole ratio range tested was 0.12–0.99 for anhydrous sodium sulfate/water, and 0.16–2.55 for sulfuric acid/anhydrous sodium sulfate.     

Determination of 30 Free Fatty Acids in Two Famous Tibetan Medicines by HPLC with Fluorescence Detection and Mass Spectrometric Identification

A simple and sensitive high-performance liquid chromatographic (HPLC) method with fluorescence detection and mass spectrometric identification has been developed for analysis of 30 long-chain and short-chain free fatty acids (FFAs). The fatty acids were derivatized to their esters with 1-[2-(p-toluenesulfonate)ethyl]-2-phenylimidazole-[4,5-f]-9,10-phenanthrene (TSPP) in N,N-dimethylformamide (DMF) at 90 °C with anhydrous K₂CO₃ as catalyst. A mixture of C₁–C₃₀ fatty acids was completely separated within 60 min by gradient elution on a reversed-phase C₈ column. Qualitative identification of the acids was performed by atmospheric-pressure chemical ionization mass spectrometry (APCI–MS) in positive-ion mode. The fluorescence excitation and emission wavelengths were 260 and 380 nm, respectively. Quantitative determination of the 30 acids in two Tibetan medicines Gentiana straminea and G. dahurica was performed. The results indicated that the medicines contained many FFAs. Linear correlation coefficients for the FFA derivatives were >0.9991. Relative standard deviations (RSDs, n = 6) for the fatty acid derivatives were <3%. Detection limits (at a signal-to-noise ratio of 3:1) were 3.1–38 fmol. When the fatty acid derivatives were determined in the two real samples results were satisfactory and the sensitivity and reproducibility of the method were good.