Simultaneous Determination Of Mono Research Articles

Simultaneous determination of mono-, di-, oligo- and polysaccharides via planar chromatography in 4 different prebiotic foods and 60 naturally degraded inulin samples

Oligo- and polysaccharides, especially fructooligosaccharides and inulin, are increasingly used as food ingredients. They are reported to stimulate the growth of bifidobacteria and are therefore used as prebiotics. As mono-, di-, oligo- and polysaccharides can together be present in food, an HPTLC method was developed for analyzing all in a single development. This method was used for both, effective food screening and quantification on the same plate. After a minimal sample preparation (aqueous extraction, dilution and filtration) and application, the samples were separated on an HPTLC plate silica gel 60 with acetonitrile - water 4:1 (V/V), containing 3.6 mM natural product reagent A. For a good reproducibility of the separation, the control of the layer activity was recommended. For up to 20 samples in parallel, the HPTLC analysis took 45 min (2.3 min/sample) with running costs of ca. 7 Euro (0.35 Euro/sample). Determination coefficients of the calibration curves were obtained between 0.9980 and 0.9998. The high degree of automation proved the method to be robust and suited for routine analysis, especially in food control. The newly developed method was successfully tested with 4 different prebiotic food and 60 naturally degraded inulin samples. A minimal sample preparation along with the determination of the intact inulin and FOS allowed the evaluation of the natural inulin degradation profile, as shown for naturally degraded inulin samples. This fast analysis might also be of interest in other fields that study, for example, plant breeding, edible insects, functional feed and metabolic processes.

Simultaneous determination of mono- and disubstituted polyfluoroalkyl phosphates in drinking water by liquid chromatography–electrospray tandem mass spectrometry

A sensitive liquid chromatography–electrospray tandem mass spectrometry method was established for the simultaneous determination of five monosubstituted polyfluoroalkyl phosphates (monoPAPs) and eight disubstituted polyfluoroalkyl phosphates (diPAPs) in drinking water. Complete separation and good retention for 13 polyfluoroalkyls phosphates (PAPs) were achieved with a Waters ACUITY UPLC BEH C8 column using a mixture of methanol/water containing 0.1% NH4OH as the mobile phases. Extraction of drinking water samples was performed on weak anion exchange (WAX) cartridges, and the recoveries of target compounds were from 65 to 110%. The limits of quantization (LOQs) for 13 analytes were in the range of 0.4–40ng/L. This method was applied to analyze the PAPs in drinking water samples from three cities in China. Of the 13 PAPs, six PAPs including 6:2 monoPAP (13.0ng/L), 8:2 monoPAP (3.6ng/L), 10:1 monoPAP (4.3–70.3ng/L), 10:2 monoPAP (1.4–5.6ng/L), 8:2 diPAP (0.10ng/L), and 10:1 diPAP (0.8–3.8ng/L) were detected.

Simultaneous Determination of Mono- and Dicarboxylic Acids, ω-Oxo-carboxylic Acids, Midchain Ketocarboxylic Acids, and Aldehydes in Atmospheric Aerosol Samples

This paper describes a method for the simultaneous determination of monocarboxylic acids (C6-C34), dicarboxylic acids (C2-C24), omega-oxo-carboxylic acids (C2-C9), ketocarboxylic acids (pyruvic and pinonic acid), and select aldehydes (glyoxal, methylglyoxal, and nonanal) in atmospheric particles. Quantification of these compounds gives information on important chemical characteristics of aerosols for source apportioning of aerosol organics and for studying atmospheric processes leading to secondary organic aerosol formation. These target analytes were determined as their butyl ester or butyl acetal derivatives using gas-chromatography mass spectrometry. The method is modified from a method described by Kawamura. Kawamura's original method involved a water extraction step, which practically restricted the method to the determination of only those compounds that are water-soluble. Our method eliminates the water extraction step and combines extraction and derivatization of the target compounds in one step. A mixture of hexane/butanol/BF3 simultaneously derivatizes the polar function groups (i.e., -COOH, -C=O) and extracts the target analytes from the aerosol filter substrates. A prominent advantage of our method is improved recoveries for the more volatile analytes in the target compound classes as a result of eliminating the water evaporation step. Recoveries better than 66% were obtained for the target analytes, including the relatively volatile ones. This improvement for the light species has allowed detection of a new midchain ketocarboxylic acid, 4-oxopentanoic acid, which would have escaped detection by the Kawamura method because of its high susceptibility to evaporative loss. Examples are presented to demonstrate the use of this method in analysis of ambient aerosol samples.

Simultaneous determination of monofluoroacetate, difluoroacetate and trifluoroacetate in environmental samples by ion chromatography

A method is reported for the sensitive, simultaneous determination of mono- (MFA), di- (DFA), and trifluoroacetates (TFA) by ion chromatography (IC). These species were separated using a Dionex AS17 anion-exchange column employed with a potassium hydroxide gradient (via a Dionex EG40 eluent generator) and suppressed conductivity detection. The fluoroacetates were successfully separated from a range of inorganic and organic species likely to be present in environmental samples, in a total analysis time of 35 min (including re-equilibration of the column). Detection limits for mono-, di- and trifluoroacetate were 21, 38 and 36 μg/l, respectively, determined using a signal-to-noise ratio of 3, and were obtained using a sample injection volume of 50 μl. Precision was less than 0.83% relative standard deviation (RSD) for replicate injections performed over a period of 30 days. The method was applied to the determination of monofluoroacetate in river water samples and also in carrot baits.

Direct determination of phosphorylated intracellular anabolites of stavudine (d4T) by liquid chromatography/tandem mass spectrometry.

The objective was to develop and validate a routine assay for active intracellular anabolites of stavudine (d4T), a nucleoside reverse transcriptase inhibitor in human PBMC, applicable to pharmacokinetic studies and treatment monitoring. This was achieved using liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS), which theoretically allies optimum sensitivity, specificity and high sample throughput. After cellular lysis in a Tris/methanol buffer, the extract spiked with 2[H(8)]-ATP (internal standard) is directly injected into the LC/MS/MS system. Phosphorylated metabolites of d4T as well as deoxythymidine-triphosphate, the competitor on the reverse transcriptase, are separated from d4T on a reverse-phase microbore column with ion pairing. The detection is performed in the multiple reaction monitoring (MRM) mode after drug ionisation in negative mode electrospray. The limit of quantitation for d4T-TP was 138 fmol per 7 mL blood (9.8 fmol per 10(6) cells) and CV% for repeatability and intermediate precision were lower than 15%. Stability of compounds was checked before and during the process of isolation of PBMC. Cellular samples from several d4T-treated patients were successfully analysed using this method and d4T-triphosphate and deoxythymidine triphosphate were recovered. In conclusion, we have developed and validated a routine LC/MS/MS method that allows the simultaneous determination of mono-, di- and triphosphorylated anabolites of d4T in PBMC as well as the natural corresponding triphosphate in one analysis. For the first time, the chain terminator ratio (d4T-TP/dT-TP) could be directly measured. This method can be used simply and routinely on more than 35 samples per day. Extension to other nucleoside analogues is under development.

Simultaneous determination of mono-, di-, and tributyltin in sediments by isotope dilution analysis using gas chromatography--ICPMS.

A mixed spike containing 119Sn-enriched monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) was prepared by direct butylation of 119Sn-enriched tin metal using a 1:3 molar excess of butyl chloride with iodide and triethylamine as catalysts. The isotopic composition of the different tin species in the spike solution was determined by gas chromatography- ICPMS after aqueous ethylation using sodium tetraethylborate. Reverse isotope dilution analysis was used for the characterization of the spike by means of natural MBT, DBT, and TBT standards. No species transformation was evident during derivatization from the reverse isotope dilution experiments based on the measured isotope ratios both before and after spiking. The mixed spike was applied to the simultaneous analysis of MBT, DBT, and TBT in certified reference materials, PACS-2 and CRM 646, with satisfactory results.

Simultaneous Determination of Mono-, Di-, and Trihydroxyoctadecenoic Acids in Beer and Wort

Monohydroxy, dihydroxy-, and trihydroxyoctadecenoic acids in beer and wort were simultaneously determined using gas chromatography after a solid extraction method. These three acids were detected at ppm levels in the wort. The monohydroxyoctadecenoic acids were not detected after wort boiling, but the dihydroxy- and trihydroxyoctadecenoic acids were transferred through wort boiling, fermentation and lagering into the finished beer. During the mashing using a laboratory mash bath, they gradually increased to about twice the levels those at mashing-in. The amounts of dihydroxyoctadecenoic acid and trihydroxyoctadecenoic acid in commercial beer samples varied from 0.6 to 1.6 ppm and 6 to 15 ppm, respectively.

Simultaneous Determination of Mono-, Di-, and Trinucleotides by High-Performance Liquid Chromatography Using N-(Dansyl)Ethylenediamine as a Fluorescent Derivatizing Reagent

Abstract A method for simultaneous determination of mono-, di- and trinucleotides with high sensitivity has been developed. This based on the fluorescent derivatization of nucleotides by the reaction of 5-dimethylaminonaphthaIene-l-[N-(2-aminoethyl)]sulfonamide (dansylEDA) with the phosphoric acid moiety of nucleotide, and then the resolution of fluorescent derivatives by high-performance liquid chromatography with a spectrofluoro monitor. The fluorescent dansylEDA derivatives of nucleotides were separated sharply each other. The detection limits for dansylEDA derivatives of nucleotides were between 4.7 and 20.3 pmol per 10-μ1 injection. This method was applied to analyze the yeast RNA after the generation of ribonucleoside 5′-monophosphate by nuclease P1 digestion. As a result, no more than 40 ng of RNA was needed for one analysis, and so such sensitivity of this method gives an advantage to analyze the RNA in a small scale.

海水中の微量有機スズ化合物の分析ならびにその海洋環境における挙動に関する研究 第１０報 ガスクロマトグラフィーによる海水中の微量モノ，ジおよびトリフェニルスズ化合物の同時定量

炎光光度検出器付きガスクロマトグラフィー(GC-FPD)による海水中のng/1(ppt)レベルのモノフェニルスズ(MPT),ジフェニルスズ(DPT)およびトリフェニルスズ(TPT)化合物の微量分析法を確立し,港湾海水中におけるMPT,DPTおよびTPT化合物の濃度について考察した。海水中のMPT,DPTおよびTPT化合物を,トリブチルスズ(TBT)化合物の分析法と同様に水素化ホウ素ナトリウムでフェニルスズ化合物の水素化物(MPTH,DPTHおよびTPTH)としジクロロメタンで抽出してGC-FPDで定量した。本法による海水からの三塩化モノフェニルスズ(MPTC),二塩化ジフェニルスズ(DBTC)および塩化トリフェニルスズ(TPTC)の回収率は75.0-82.4%,79.4-92.6%および84.5-91.5%であり,それらの定量限界は夏5ng/l,5ng/lおよび20ng/l(PPt)であった。本法を用いて,1989年6月から1990年6月までの1年間にわたって採取した京都府舞鶴湾の表層海水中のMPT,DPTおよびTPT化合物を定量した結果,MPTC,DBTCおよびTPTCはすべて定量限界以下(N.Dt)であった。

Simultaneous determination of mono- and bivalent cations in environmental chemistry using isocratic ion chromatography

The influence of the pH of the mobile phase ethylenediamine (EDA)/citrate on the retention behaviour of mono- and bivalent cations on a silica based cationexchange stationary phase was studied. Variation of the pH-value was accomplished either by changing the concentration of one component of the eluent or by adding potassium hydroxide or hydrochloric acid to an eluent of fixed composition. The pH range between 2.8 and 3.0 proved to be most suitable for the separation of mono- and bivalent cations. Alkali metals, alkaline earths and transition elements could be separated in a single run. Extending the pH-range up to 5.2 showed the possibility of an additional determination of more strongly retained ions, such as Pb2+ or Sr2+.

Simultaneous determination of mono- and poly(ADP-ribose) in vivo by tritium labelling and direct high-performance liquid chromatographic separation

A microanalytical method for the determination of cellular mono-, oligo- and poly(ADP-ribose) has been developed that does not involve enzymatic degradation of oligomers to ribosyladenosine. The method consists of separation of protein-bound mono-, oligo- and poly(ADP-ribose) adducts from soluble nucleotides, followed by hydrolysis and quantitative isolation of AMP [derived from mono-(ADP-ribose)proteins], oligo- and poly(ADP-ribose) by boronate affinity chromatography and subsequent isolation of these nucleotides by HPLC. cis-Diols in AMP, oligo- and poly(ADP-ribose) are selectively oxidized by periodate, then reduced by [ 3H]borohydride. Conditions for the oxidation—reduction steps were optimized, and tritiated AMP, oligo- and poly(ADP-ribose) were quantitatively determined by radiochemical analysis of these components that were isolated by reversed-phase high-performance liquid chromatography (18). A 1-pmol ADP-ribose unit under standard conditions yields 2 · 10 3–2.2 · 10 3 cpm 3H and this sensitivity can be amplified by increasing the specific radioactivity of [ 3H]borohydride.