共查询到20条相似文献,搜索用时 915 毫秒
1.
Simultaneous production of citric acid and erythritol from crude glycerol by Yarrowia lipolytica Wratislavia K1 总被引:2,自引:0,他引:2
This study shows a possible microbial process for utilization of crude glycerol generated by the biodiesel industry for citric
acid and erythritol production. Simultaneous production of citric acid and erythritol under nitrogen-limited conditions with
glycerol as the carbon source was achieved with an acetate negative mutant of Y. lipolytica Wratislavia K1 in fed-batch cultivations. The effect of the initial glycerol concentration (from 30–180 g dm−3) on the citrate and erythritol production was investigated. As a result of the experiments, maximum citric acid production
(110 g dm−3) and a very high amount of erythritol (81 g dm−3) were determined after 168 h of fed-batch cultivation with the initial glycerol concentration of 150 g dm−3 and the total glycerol concentration of 250 g dm−3. In addition, the citric acid to isocitric acid ratio of the products from this strain was 35.5:1.
Presented at the 34th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 21–25 May
2007. 相似文献
2.
R. Schindler R. Vonach B. Lendl R. Kellner 《Fresenius' Journal of Analytical Chemistry》1998,362(1):130-136
A new process control methodology for the simultaneous determination of sugars, alcohols and organic acids in wine based
on multivariate evaluation of mid-IR transmission spectra of wine samples is presented. In addition to ethanol several lower
level wine components (glucose, fructose, glycerol, citric-, tartaric-, malic-, lactic- and acetic acid) were determined.
To establish a multivariate calibration model a set of 72 calibration solutions was prepared and measured, using a novel,
fully automated sequential injection (SI) system with Fourier transform infrared (FTIR) detection. The resulting spectra were
evaluated using a partial least square (PLS) model. The developed PLS model was then applied to the analysis of real wine
samples containing 79–91 g L–1 ethanol, 5.9–8.1 g L–1 glycerol, 0.4–6.9 g L–1 glucose, 1.5–7.5 g L–1 fructose, 0.3–1.6 g L–1 citric acid, 1.0–1.7 g L–1 tartaric acid, 0.02–3.2 g L–1 malic acid, 0.4–2.8 g L–1 lactic acid and 0.15–0.60 g L–1 acetic acid, yielding results which were in good agreement with those obtained by an external reference method (HPLC-IR).
The short analysis time (less than 3 min) together with high reproducibility makes the newly developed method applicable to
process control and screening purposes (average of the standard deviations calculated from four repetitive measurements of
six different real samples: ethanol: 0.55 g L–1, glycerol: 0.037 g L–1, glucose: 0.056 g L–1, fructose: 0.036 g L–1, citric acid: 0.020 g L–1, tartaric acid: 0.010 g L–1, malic acid: 0.052 g L–1, lactic acid: 0.012 g L–1 and acetic acid: 0.026 g L–1).
Received: 21 January 1998 / Revised: 5 March 1998 / Accepted: 6 March 1998 相似文献
3.
E. Miralles R. Compa?ó M. Granados M. D. Prat 《Fresenius' Journal of Analytical Chemistry》1999,365(6):516-520
Total cyanide species are determined in a flow injection system which includes UV-photodissociation, gas-diffusion separation
and spectrofluorimetric detection. Without the irradiation step, only cyanide easily released in acid medium, i.e. labile cyanide, is determined. Cyanide diffuses through a microporous PTFE membrane from an acid donor stream to a sodium
hydroxide acceptor stream. Then, the transferred cyanide reacts with ?o-phthalaldehyde and glycine to form a highly fluorescent isoindole derivative. Complete cyanide recoveries were obtained for
the most important metal cyanide complexes found in environmental samples, excepting cobaltocyanide. The sampling frequency
for total cyanide was 4 samples h–1 and the detection limit was 0.4 μg L–1. Recoveries of total cyanide from river water obtained with this method are about 90% of those obtained with APHA Method 4500-CN C for total cyanide.
Received: 10 February 1999 / Revised: 7 May 1999 / Accepted: 13 May 1999 相似文献
4.
The chiral separation of dansyl-amino acids has been performed by capillary zone electrophoresis using ?β-cyclodextrin as
a chiral selector, urea as an additive and 2-propanol and methanol as organic modifiers. The enantiomeric separations of dansyl-amino
acids were investigated in aqueous medium and compared with the separation in mixed aqueous-organic medium as background electrolytes.
The separation conditions, (concentration of buffer, β-cyclodextrin, methanol, urea and the pH value of buffer) were optimized.
In the absence of organic modifier, only five pairs of 8 separated dansyl-amino acids were resolved when run separately. A
mixture of up to eight chiral amino acids can be baseline resolved in less than 19 min by β-cyclodextrin-modified capillary
zone electrophoresis with a buffer of 60 mmol L–1 H3BO3-KCl/40 mmol L–1 NaOH (pH 9.0), 4 mol L–1 urea, 100 mmol L–1β-cyclodextrin and 10% (v/v) methanol.
Received: 15 March 1999 / Revised: 10 May 1999 / Accepted: 12 May 1999 相似文献
5.
Application of a hexapole collision and reaction cell in ICP-MS Part II: Analytical figures of merit and first applications 总被引:1,自引:0,他引:1
I. Feldmann N. Jakubowski C. Thomas D. Stuewer 《Fresenius' Journal of Analytical Chemistry》1999,365(5):422-428
The application of an ion-guiding gas-filled hexapole collision/reaction cell in ICP-MS has been studied to characterize
the analytical figures of merit that can be achieved with this approach. For the elements investigated, application of a buffer
and a reaction gas resulted in improved sensitivities which are lowest for Be with about 7 · 107 cps per μg mL–1 and highest for Ba with about ?6 · 108 cps per μg mL–1. Relative standard deviations (RSD) < 0.1% were obtained. Application of the reaction gas H2 was used to suppress polyatomic ions caused by argon. The reduction amounted up to four orders of magnitude so that elements
such as Ca, K, Cr, Fe, As and Se could be analyzed in nitric and hydrochloric acid or in methanol. Detection limits of 6 pg
mL–1 for Cr in 2% methanol, 23 pg mL–1 for As and 9 pg mL–1 for Se in 0.28 M HCl were achieved. For other elements detection limits ?< 1 pg mL–1 were realized in the medium and high mass range. Accuracy was proved using the NIST 1643d standard reference material.
Received: 10 May 1999 / Revised: 4 June 1999 / Accepted: 12 June 1999 相似文献
6.
Jaw-Cherng Hsu Chin-Hung Chang C.-Y. Liu 《Analytical and bioanalytical chemistry》1998,362(6):514-521
A silica based sorbent with an anion complexone polymer coating, [24]ane-N6 macrocycle, was prepared. The chelation properties of this material were investigated by elemental analysis, infrared spectra
and Voige’s method. The polymer-coated silica column (25– 40 μm, 100 × 4.6 mm i.d.) was employed for trace metal analyses.
Oxalic acid, malonic acid, succinic acid, citric acid, phthalic acid and acetic acid were used as mobile phases. Their retention
characteristics were elucidated. Oxalic acid was found to be the most effective eluent. With a mobile phase consisting of
oxalic acid (25 mM) and sodium nitrate (25 mM) at pH 4.2, the separation of copper(II), cadmium(II), cobalt(II) and zinc(II)
in sea water could be achieved. The identification of metal ions was performed at 510 nm using 4(2-pyridylazo)resorcinol (1
× 10–4 M) as post column reagent. The limits of detection were 5 × 10–7 M, 1 × 10–5 M, 3 × 10–5 M and 2 × 10–6 M for copper(II), cadmium(II), cobalt(II) and zinc(II) based on three times the standard deviation of the response for the
lowest concentration (n = 5) in the chromatogram with a sample volume of 50 μL. For evaluation of data reliability, oyster
tissue (NIST SRM 1566 a) was studied with the proposed system.
Received: 9 February 1998 / Revised: 15 May 1998 / Accepted: 16 June 1998 相似文献
7.
S. M. Sultan Aladdin M. Almuaibed A. Townshend 《Fresenius' Journal of Analytical Chemistry》1998,362(1):167-169
A new flow injection chemiluminescence method for the assay of medazepam is explored. The method involves the use of permanganate
in sulfuric acid for the oxidation of medazepam with the emission of chemiluminescence detected by a photomultiplier tube.
A simplex procedure was employed for optimising the conditions for high sensitivity detection, which were found to be 1.03
× 10–3 mol L–1 permanganate, 0.153 mol L–1 sulfuric acid and 3.43 mL min–1 flow rate. The linear calibration range was 3.7 × 10–5 to 1.7 × 10–3 mol L–1. The detection limit (3σ) and the sample throughput were 1.85 × 10–5 mol L–1 and 100 per hour, respectively. The relative standard deviation for 5 replicate determinations of 1.9 × 10–4 mol L–1 medazepam was 0.15%. Common excipients (starch, glucose, maltose, lactose) used in pharmaceutical preparations had no effect.
Received: 2 February 1998 / Revised: 20 May 1998 / Accepted: 25 May 1998 相似文献
8.
N. Alizadeh S. Ershad H. Naeimi H. Sharghi M. Shamsipur 《Fresenius' Journal of Analytical Chemistry》1999,365(6):511-515
A PVC membrane electrode for copper(II) ions based on a recently synthesized naphthol-derivative Schiff’s base as membrane
carrier was prepared. The sensor exhibits a Nernstian response for Cu2+ ions over a wide concentration range (5.0 × 10–6–5.0 × 10–2 mol/L) with a detection limit of 3.1 × 10–6 mol/L (0.2 μg/mL). It has a very short response time of about 5 s and can be used for ?3 months without any divergence in
potential. The proposed electrode revealed good selectivities over a wide variety of other cations including alkali, alkaline
earth, transition and heavy metal ions and could be used in a pH range of 4.0–7.0. It was successfully applied to the direct
determination and potentiometric titration of copper ion.
Received: 23 February 1999 / Revised: 4 May 1999 / Accepted: 5 May 1999 相似文献
9.
A. Ruiz Medina M. L. Fernández de Córdova A. Molina Díaz 《Analytical and bioanalytical chemistry》1999,365(7):619-624
A new, sensitive and very simple spectrofluorimetric biparameter sensor is described for the determination of salicylamide
and/or salicylic acid in pharmaceutical preparations. The method integrates the transitory retention and fluorescence detection
of both compounds on Sephadex QAE A-25 resin packed into a conventional flow-through cell. A monochannel manifold with two
alternative carriers is used. At pH 2.0 (first carrier) salicylic acid is selectively retained on the solid support and after
developing the analytical signal it is desorbed. At pH 11.0 (second carrier) both salicylic acid and salicylamide are simultaneously
and transitorily retained on the solid, the analytical signal now corresponding to both analytes. The monochromators were
tuned at 260 (excitation) and 415 (emission) nm, respectively. The calibration graph for salicylamide is linear over the range
0.01 to 0.32 μg mL–1 and for salicylic acid from 0.04 to 1.0 μg mL–1 in the presence of each other. The relative standard deviation and the sampling frequency for the determination of salicylamide
(0.20 μg mL–1) and salicylic acid (0.50 μg mL–1) were 1.1% and 35 h–1, and 0.9% and 45 h–1, respectively. Good results on application to individual determination or mixture resolution in pharmaceutical samples testify
to the usefulness of the proposed sensor.
Received: 20 April 1999 / Revised: 7 June 1999 / Accepted: 12 June 1999 相似文献
10.
Michael Winklmair Andreas J. Schuetz M. G. Weller Reinhard Niessner 《Fresenius' Journal of Analytical Chemistry》1999,363(7):619-624
A new, sensitive and very simple spectrofluorimetric biparameter sensor is described for the determination of salicylamide
and/or salicylic acid in pharmaceutical preparations. The method integrates the transitory retention and fluorescence detection
of both compounds on Sephadex QAE A-25 resin packed into a conventional flow-through cell. A monochannel manifold with two
alternative carriers is used. At pH 2.0 (first carrier) salicylic acid is selectively retained on the solid support and after
developing the analytical signal it is desorbed. At pH 11.0 (second carrier) both salicylic acid and salicylamide are simultaneously
and transitorily retained on the solid, the analytical signal now corresponding to both analytes. The monochromators were
tuned at 260 (excitation) and 415 (emission) nm, respectively. The calibration graph for salicylamide is linear over the range
0.01 to 0.32 μg mL–1 and for salicylic acid from 0.04 to 1.0 μg mL–1 in the presence of each other. The relative standard deviation and the sampling frequency for the determination of salicylamide
(0.20 μg mL–1) and salicylic acid (0.50 μg mL–1) were 1.1% and 35 h–1, and 0.9% and 45 h–1, respectively. Good results on application to individual determination or mixture resolution in pharmaceutical samples testify
to the usefulness of the proposed sensor.
Received: 20 April 1999 / Revised: 7 June 1999 / Accepted: 12 June 1999 相似文献
11.
José L. F. C. Lima C. Delerue-Matos M. Carmo M. C. V. F. Vaz Jeanine Silva 《Fresenius' Journal of Analytical Chemistry》1999,364(3):266-269
A flow injection analysis (FIA) system with potentiometric detection has been developed for the determination of citric acid
in commercial fruit juices using a copper-selective tubular electrode. It consists of the complexation of citrate ion with
copper (II) ion, monitoring the free copper (II) concentration. Linear relationships between the potential and log concentrations
of citric acid in the range of 1 × 10–3 mol/L – 1 × 10–2 mol/L were attained with samples injected in the system without prior treatment. Repeatability was determined by assessing
the relative standard deviation for ten replicate injections of different juice samples which varied from 1.2% to 3.0%. The
results provided by the automated system were compared with those of an enzymatic conventional method used for the analysis
of citric acid in food and a relative deviation of less than 4.0% was found. Recovery trials resulted in values from 97.0%
to 101.0%. The system allows a sampling frequency of 60 samples/h.
Received: 22 October 1998 / Revised: 14 December 1998 / Accepted: 16 December 1998 相似文献
12.
A continuous flow atomic absorption spectrometric system was used to develop an efficient on-line preconcentration-elution
procedure for the determination of iodide traces. Chromium (VI) is introduced into the flow system and is reduced to chromium
(III) in acid medium proportionally to the iodide present in the sample. The Cr(III) reduced by iodide is retained on a minicolumn
packed with a poly(aminophosphonic acid) chelating resin, while unreduced Cr(VI) is not retained. Reduced Cr(III) is preconcentrated
by passing the sample containing iodide through the system during 3 min, and is then eluted with 0.5 mol L–1 hydrochloric acid and determined by flame atomic absorption spectrometry (FAAS). The detection limit (3σ) obtained is 2.5
μg L–1. Other ions typically present in waters do not interfere. The proposed method allows the determination of iodide in the range
6–220 μg L–1 with a relative standard deviation of 2.7% at a rate of 17 samples h–1. The method has been applied to the determination of iodide in tap and sea waters.
Received: 16 September 1999 / Revised: 15 November 1999 / Accepted: 19 November 1999 相似文献
13.
Three acetate mutants of the yeast species Yarrowia lipolytica were screened using batch cultivation. The strain Y. lipolytica 1.31 was found to be the most suitable for citric acid production from raw glycerol, a by-product of biodiesel production
from rapeseed oil. At the initial concentration of glycerol of 200 g dm−3, the citric acid production of 124.5 g dm−3, yield of 0.62 g g−1, and productivity of 0.88 g dm−3 h−1 were achieved.
Presented at the 33rd International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 22–26 May
2006. 相似文献
14.
Sérgio L. C. Ferreira Marcus L. S. F. Bandeira Valfredo A. Lemos Hilda C. dos Santos A. C. Spinola Costa Djane S. de Jesus 《Analytical and bioanalytical chemistry》1997,357(8):1174-1178
A simple and very sensitive method has been developed for the determination of ascorbic acid based on the oxidation of ascorbic
acid to dehydroascorbic acid by iron(III), followed by a complexation of iron(II) with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol(Br-PADAP).
The iron(II) complex is formed immediately, with absorption maxima at 560 and 748 nm and a molar absorptivity of 1.31 × 105 l mole–1cm–1 and 5.69 × 104 l mole–1cm–1, respectively. The ascorbic acid determination is possible with a linear range up to 2.4 μg ml–1, a calibration sensitivity of 0.744 ml μg–1 at 560 nm and 0.323 ml μg–1 at 748 nm, and a detection limit of 15 ng ml–1 and 44 ng ml–1, respectively. The procedure was used for the ascorbic acid determination in several fruit juices and pharmaceutical formulations.
The results demonstrated a good precision (R.S.D. < 1%) and are in agreement with those obtained with others methods. The
Br-PADAP method proposed is six times more sensitive than the method using the iron(II)-1,10-phenanthroline system.
Received: 7 May 1996 / Revised: 1 July 1996 / Accepted: 8 August 1996 相似文献
15.
I. V. Pletnev Nataliya V. Shvedene Irina V. Lyutikova Inna A. Nazarova Ilya M. Litvak Irina V. Mikhura Yury A. Zolotov 《Fresenius' Journal of Analytical Chemistry》1999,364(8):682-685
Arylboronic acids are used as novel carriers for membrane electrodes suitable for direct potentiometric determination of
the catecholamine drug dobutamine. The carriers are capable of binding diol groups of catecholamines; solvent extraction data
confirm the formation of an 1 : 1 complex. For the electrode based on octyloxyphenylboronic acid, the slope of electrode function
is S = 58 mV decade–1; the detection limit is 1.7 · 10–5 mol/L, the linear range 5 · 10–4– 1 · 10–2 mol/L, the response time 10–20 s. The results suggest the potential use of boronic carriers for the detection of biogenic
catecholamines.
Received: 25 November 1998 / Revised: 2 March 1999 / Accepted: 11 March 1999 相似文献
16.
Sérgio L. C. Ferreira Marcus L. S. F. Bandeira Valfredo A. Lemos Hilda C. dos Santos A. C. Spinola Costa Djane S. de Jesus 《Fresenius' Journal of Analytical Chemistry》1997,357(8):1174-1178
A simple and very sensitive method has been developed for the determination of ascorbic acid based on the oxidation of ascorbic
acid to dehydroascorbic acid by iron(III), followed by a complexation of iron(II) with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol(Br-PADAP).
The iron(II) complex is formed immediately, with absorption maxima at 560 and 748 nm and a molar absorptivity of 1.31 × 105 l mole–1cm–1 and 5.69 × 104 l mole–1cm–1, respectively. The ascorbic acid determination is possible with a linear range up to 2.4 μg ml–1, a calibration sensitivity of 0.744 ml μg–1 at 560 nm and 0.323 ml μg–1 at 748 nm, and a detection limit of 15 ng ml–1 and 44 ng ml–1, respectively. The procedure was used for the ascorbic acid determination in several fruit juices and pharmaceutical formulations.
The results demonstrated a good precision (R.S.D. < 1%) and are in agreement with those obtained with others methods. The
Br-PADAP method proposed is six times more sensitive than the method using the iron(II)-1,10-phenanthroline system.
Received: 7 May 1996 / Revised: 1 July 1996 / Accepted: 8 August 1996 相似文献
17.
Combination of various analytical techniques for speciation of low molecular weight aluminium complexes in plant sap 总被引:1,自引:0,他引:1
T. Bantan R. Milai B. Mitrovi B. Pihlar 《Fresenius' Journal of Analytical Chemistry》1999,365(6):545-552
The possibilities for speciation of low molecular weight aluminium organic acid complexes (LMW-Al) in plant sap were investigated
by applying a combination of various chromatographic and spectroscopic techniques. The behavior of different LMW-Al complexes
was investigated in synthetic aqueous solutions on anion and cation exchange fast protein liquid chromatography (FPLC) columns
with inductively coupled plasma – atomic emission spectrometry (ICP-AES) or electrothermal atomic absorption spectrometry
(ETAAS) detection. Plant sap of Sempervivum tectorum with a high concentration of Al (9.3 μg cm–3) and Sansevieria trifasciata with an appreciably lower Al concentration (0.065 μg cm–3) were analyzed. The speciation study in plant sap indicated that the species present in these samples, existed as negatively
charged LMW-Al complexes which were eluted at the retention time typical for Al-citrate and Al-aconitate. In order to identify
Al binding ligands eluted under the chromatographic peak analysis by electrospray ionization (ESI)-MS technique using Z spray
ion source were also applied. The predominant LMW-Al negatively charged complexes in Sempervivum tectorum and Sansevieria trifasciata were found to be Al-citrate and Al-aconitate. It was shown that other LMW organic acids do not form complexes with Al in
the samples studied.
Received: 5 April 1999 / Revised: 15 May 1999 / Accepted: 27 May 1999 相似文献
18.
The suitability of 1-nitroso-2-naphthol as a complexing agent for on-line preconcentration of copper using RP-C18 material in a microcolumn with flow injection coupled with flame atomic absorption spectrometry (FI-FAAS) has been tested.
Various parameters affecting complex formation, such as pH, sample flow rate, etc. and its elution into the nebulizer of FAAS
were optimized. ?A 5 × 10–3 mol/L reagent was on-line mixed with aqueous sample solution acidified with 0.1% (v/v) nitric acid ?(pH 3–4) and flowed through
the microcolumn for 30 s. The adsorbed complexes in the microcolumn were eluted with ethanol in 10 s into the nebulizer of
FAAS. A good precision (1.7% for 50 μg/L copper, n = 12), high enrichment factor (19) with detection limit (3σ) 2.0 μg/L,
and sample throughput (90 h–1) were obtained. The method was applied to certified reference materials seawater, mussel (biological), NBS-362 and NBS-364
(special low alloy steel), for the determination of copper, and the results were in good agreement with the certified values.
Received: 4 May 1999 / Revised: 25 June 1999 / Accepted: 29 June 1999 相似文献
19.
M. C. Yebra M. F. Enríquez A. García A. Moreno-Cid 《Analytical and bioanalytical chemistry》2001,370(1):64-68
A minicolumn packed with poly(aminophosphonic acid) chelating resin incorporated in an on-line preconcentration system for
flame atomic-absorption spectrometry was used to determine ultratrace amounts of lead in mussel samples at μg L–1 level. The preconcentrated lead was eluted with hydrochloric acid and injected directly into the nebulizer for atomization
in an air-acetylene flame for measurement. The performance characteristics of the determination of lead were: preconcentration
factor 26.8 for 1 min preconcentration time, detection limit (3σ) in the sample digest was 0.25 μg g–1 (dry weight) for a sample volume of 3.5 mL and 0.2 g sample (preconcentration time 1 min), precision (RSD) 2.3% for 25 μg
L–1 and 2.0% for 50 μg L–1. The sampling frequency was 45 h–1. The method was highly tolerant of interferences, and the results obtained for the determination of lead in a reference material
testify to the applicability of the proposed procedure to the determination of lead at ultratrace level in biological materials
such as mussel samples.
Received: 1 November 2000 / Revised: 8 January 2001/ Accepted: 11 January 2001 相似文献
20.
Characterization and application of an electrode modified by mechanically immobilized copper hexacyanoferrate 总被引:1,自引:0,他引:1
A newly modified electrode was prepared by mechanical immobilization of copper hexacyanoferrate (CuHCF) on a graphite electrode.
The modified electrode was characterized by cyclic voltammetric experiments. The effect of different background electrolytes,
pHs and scan rates on the electrochemical behaviour of the electrode has been evaluated. In NH4Cl two reversible redox peaks were observed. The first redox peak corresponding to Cu+/Cu2+ is observed only in this medium. The second redox peak corresponds to the Fe(CN)6
4–/Fe(CN)6
3– couple. Both anodic peaks were used for catalytic oxidation of ascorbic acid. As the anodic current for catalytic oxidation
was proportional to the amount of ascorbic acid, an analytical method was developed for the determination of ascorbic acid
in commercial samples.
Received: 26 May 1998 / Revised: 15 March 1999 / Accepted: 20 March 1999 相似文献