共查询到20条相似文献,搜索用时 15 毫秒
1.
A. R. Jalilian S. Shanehsazzadeh M. Akhlaghi J. Garousi S. Rajabifar M. B. Tavakoli 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(1):123-129
Gonadorelin was successively labeled with [67Ga]-gallium chloride after residulation with freshly prepared cyclic DTPA-dianhydride. The best results of the conjugation
were obtained by the addition of 1 mg of a gonadorelin to a glass tube pre-coated with DTPA-dianhydride (0.33 mg) at 25 °C
with continuous mild stirring for 1 hour. Radio thin layer chromatography showed an overall radiochemical purity of >90% at
optimized conditions after labeling. HPLC showed a radiochemical purity more than 95% (specific activity = 400–450 GBq/M).
The stability of the radioconjugate was tested in presence of human serum at 37 °C. Preliminary in vivo studies in normal
rats were performed to determine the biodistribution of the conjugate up to 48 hours. The breast and ovaries uptakes were
significantly high in first 15-minute post injection which is in agreement with the other reports regarding the presence of
specific GnRH receptors. This tracer can be used in detection of GnRH receptor biodistribution in various diseases and malignancies. 相似文献
2.
H. Sadeghpour A. R. Jalilian M. Akhlaghi M. Kamali-dehghan M. Mirzaii A. Shafiee 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(1):117-122
Human recombinant erythropoietin (EPO) was successively labeled with [111In]-indium chloride after conjugation with freshly prepared cyclic DTPA-dianhydride (ccDTPA). The best results of the conjugation
were obtained by the addition of 100 i.u. of an EPO pharmaceutical solution (in phosphate buffer, pH 7.5) to a glass tube
pre-coated with DTPA-dianhydride (0.01 mg) at 25 °C with continuous mild stirring for 30 minutes. Radio thin layer chromatography
(RTLC), instant thin layer chromatography (ITLC) and high performance liquid chromatography (HPLC) showed overall radiochemical
purity of higher than 95% at optimized conditions (specific activity = 1.2–1.5 GBq/mg, labeling efficiency 80%). Preliminary
in vivo studies in normal rat model was performed to determine the biodistribution of the radiotracer up to 1 hour using scarification.
The high kidney uptake of the tracer was consistent with the reported EPO receptor distribution. 相似文献
3.
A. R. Jalilian J. Garousi M. Akhlaghi P. Rowshanfarzad 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(3):791-796
In order to target insulin receptors in various diabetic and insulinoma conditions, human recombinant insulin was successively
labeled with [111In]-indium chloride after conjugation with freshly prepared cyclic DTPA-dianhydride (ccDTPA). The best results of the conjugation
were obtained by addition of 0.5 mL of an insulin pharmaceutical solution (5 mg/mL, in phosphate buffer, pH 8) to a glass
tube pre-coated with DTPA-dianhydride (0.01 mg) at 25 °C with continuous mild stirring for 30 minutes. Radio-thin layer chromatography
(RTLC), instant thin layer chromatography (ITLC) and high performance liquid chromatography (HPLC) have shown an overall radiochemical
purity of higher than 93% at optimized conditions (specific activity = 550–750 MBq/mg, radiochemical yield =81%). The white
blood cell labeling capacity of the tracer was determined up to 4 hours at 37 °C. Preliminary in vivo studies in normal rat
model was performed to determine the biodistribution of the radiotracer up to 48 hours. It showed a high liver and spleen
uptake of the tracer which is consistent with other reported radiolabeled insulins. SPECT images have also shown high liver
accumulation of the tracer. 相似文献
4.
Babu Rao Chandu Sreekanth Nama Kanchanamala Kanala Balasekhara Reddy Challa Rihana Parveen Shaik Mukkanti Khagga 《Analytical and bioanalytical chemistry》2010,398(3):1367-1374
A novel simple, sensitive, selective, and rapid high-performance liquid chromatography coupled with tandem mass spectrometry
method was developed and validated for quantification of riluzole in human plasma. The chromatography was performed by using
a Zorbax-SB-C18 (4.6 × 75 mm, 3.5 μm) column , isocratic mobile phase 0.1% formic acid/acetonitrile (10:90 v/v), and an isotope-labeled
internal standard (IS), [13C,15N2]riluzole. The extraction of drug and internal standard was performed by liquid–liquid extraction and analyzed by MS in the
multiple reaction monitoring (MRM) mode using the respective [M+H]+ ions, m/z 235.0/165.9 for riluzole and m/z 238.1/169.0 for the IS. The calibration curve was linear over the concentration range 0.5–500.0 ng/ml for riluzole in human
plasma. The limit of quantification (LOQ) was demonstrated at 0.5 ng/ml. The within-batch and between-batch precision were
0.6–2.3% and 1.4–5.7%, and accuracy was 97.1–101.1% and 98.8–101.2% for riluzole respectively. Drug and IS were eluted within
3.0 min. The validated method was successfully applied in a bioequivalence study of riluzole in human plasma. 相似文献
5.
A. R. Jalilian L. Mirsadeghi Y. Yari-kamrani P. Rowshanfarzad M. Kamali-dehghan M. Sabet 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(3):563-568
Copper-64 was produced as a by-product of 55Co via 64Ni(p,n)64Cu by 15 MeV proton bombardment of natNi resulting in a thick target yield of 5.31 MBq/μAh (143.5 μCi/μAh) and a radiochemical separation yield of 95% (radionuclide
purity >97% after 25 hours of bombardment). Rituximab was successively labeled with [64Cu]-CuCl2. N-succinimidyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA-NHS) was prepared at 25 °C using DOTA and
N-hydroxy succinimide (NHS) in CH2Cl2 followed by the addition of 1 ml of a Rituximab pharmaceutical solution. Radiolabeling was performed at 37 °C in 3 hours.
Radio thin-layer chromatography showed an overall radiochemical purity of 90–95% at optimized conditions (specific activity=30
GBq/mg, labeling efficacy; 82%) using various chromatography systems. The final isotonic 64Cu-DOTA-Rituximab complex was passed through a 0.22 μm filter and checked by gel electrophoresis for radiolysis control. Stability
of the final product was checked in the formulation and in presence of human serum at 37 °C. 相似文献
6.
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
7.
A multi-component method focussing on thorough sample preparation has been developed for simultaneous analysis of swine manure
for three classes of antibiotic—tetracyclines, sulfonamides, and tylosin. Liquid manure was initially freeze-dried and homogenised
by pulverization before extraction by pressurised liquid extraction. The extraction was performed at 75°C and 2,500 psig in
three steps using two cycles with 0.2 mol L−1 citric acid buffer (pH 4.7) and one cycle with a mixture of 80% methanol with 0.2 mol L−1 citric acid (pH 3). After liquid–liquid extraction with heptane to remove lipids, the pH of the manure was adjusted to 3
with formic acid and the sample was vacuum-filtered through 0.6 μm glass-fibre filters. Finally the samples were pre-concentrated
by tandem SPE (SAX-HLB). Recoveries were determined for manure samples spiked at three concentrations (50–5,000 μg kg−1 dry matter); quantification was achieved by matrix-matched calibration. Recoveries were >70% except for oxytetracycline (42–54%),
sulfadiazine (59–73%), and tylosin (9–35%) and did not vary with concentration or from day-to-day. Limits of quantification
(LOQ) for all compounds, determined as a signal-to-noise ratio of 10, were in the range 10–100 μg kg−1 dry matter. The suitability of the method was assessed by analysis of swine manure samples from six different pig-production
sites, e.g. finishing pigs, sows, or mixed production. Residues of antibiotics were detected in all samples. The largest amounts
were found for tetracyclines (up to 30 mg kg−1 dry matter for the sum of CTC and ECTC). Sulfonamides were detected at concentrations up to 2 mg kg−1 dry matter (SDZ); tylosin was not detected in any samples.
相似文献
8.
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
9.
Hassan Yousefnia Edalat Radfar Amir Reza Jalilian Ali Bahrami-Samani Simindokht Shirvani-Arani Azim Arbabi Mohammad Ghannadi-Maragheh 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(1):199-209
Rituximab was successively labeled with 177Lu-lutetium chloride. 177Lu chloride was obtained by thermal neutron flux (4 × 1013 n cm−2 s−1) of natural Lu2O3 sample with a specific activity of 2.6–3 GBq/mg. The macrocyclic bifunctional chelating agent, N-succinimidyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic
acid (DOTA-NHS) was prepared at 25 °C using DOTA, N-hydroxy succinimide (NHS) in CH2Cl2. DOTA-rituximab was obtained by the addition of 1 mL of a rituximab pharmaceutical solution (5 mg/mL, in phosphate buffer,
pH 7.8) to a glass tube pre-coated with DOTA-NHS (0.01–0.1 mg) at 25 °C with continuous mild stirring for 15 h. Radiolabeling
was performed at 37 °C in 24 h. Radio-thin layer chromatography showed an overall radiochemical purity of >98% at optimized
conditions (specific activity = 444 MBq/mg, labeling efficacy; 82%). The final isotonic 177Lu-DOTA-rituximab complex was checked by gel electrophoresis for structure integrity control. Radio-TLC was performed to ensure
that only one species was present after filtration through a 0.22 μm filter. Preliminary biodistribution studies in normal
rats were carried out to determine complex distribution of the radioimmunoconjugate up to 168 h. The biodistribution data
were in accordance with other antiCD20 radioimmunoconjugates already reported. 相似文献
10.
C. Sanchez-Pedreño M. S. García J. A. Ortuño M. I. Albero E. Ballester 《Analytical and bioanalytical chemistry》2001,369(7-8):680-683
A flow-through bulk optode based on the use of 1-(2-pyridylazo)-2-naphthol (PAN) immobilized in a plasticized poly(vinyl
chloride) membrane entrapped in a cellulose support, in conjuntion with the flow injection analysis technique, is proposed
for the determination of manganese(II). The calibration graph obtained at 570 nm was linear in the range 0.27–27.5 mg L–1 (5 × 10–6– 5 × 10–4 M) Mn(II) with a detection limit of 0.18 mg L–1. The coefficients of variation of the sensor response for 5.5 mg L–1 of Mn(II) were ±0.22% for consecutive measurements (n = 10), ±0.48% between days (n = 5) and ±0.38% between different membranes
(n = 6). The sensor was readily regenerated with the carrier acetic acid/acetate buffer of pH 4.5. The method was applied
to the determination of manganese in steels, waters and lemon tree leaves.
Received: 13 December 2000 / Revised: 25 January 2001 / Accepted: 26 January 2001 相似文献
11.
Yousef Fazaeli Amir R. Jalilian Mostafa M. Amini Ali Rahiminejad-kisomi Saeed Rajabifar Fatemeh Bolourinovin Sedigheh Moradkhani 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(1):17-24
[67Ga]labeled tetraphenyl porphyrin ([67Ga]-TPP) was prepared using freshly prepared [67Ga]GaCl3 and tetraphenyl porphyrin (TPPH2) for 30–60 min at 25 °C (radiochemical purity: >97 ± 1% ITLC, >98 ± 0.5% HPLC, specific activity: 13–14 GBq/mmol). Stability
of the complex was checked in final formulation and human serum for 24 h. The partition coefficient was calculated for the
compound (log P 1.89). The biodistribution of the labeled compound in vital organs of wild-type rats was studied using scarification studies
and SPECT imaging up to 24 h. A detailed comparative pharmacokinetic study performed for 67Ga cation and [67Ga]-TPP. The complex is mostly washed out from the circulation through kidneys and can be an interesting tumor imaging/targeting
agent due to low liver uptake and rapid excretion through the urinary tract. 相似文献
12.
MSPD procedure for determining buprofezin,tetradifon, vinclozolin,and bifenthrin residues in propolis by gas chromatography–mass spectrometry 总被引:1,自引:0,他引:1
dos Santos TF Aquino A Dórea HS Navickiene S 《Analytical and bioanalytical chemistry》2008,390(5):1425-1430
A simple and effective extraction method based on matrix solid-phase dispersion (MSPD) was developed to determine bifenthrin,
buprofezin, tetradifon, and vinclozolin in propolis using gas chromatography–mass spectrometry in selected ion monitoring
mode (GC–MS, SIM). Different method conditions were evaluated, for example type of solid phase (C18, alumina, silica, and Florisil), the amount of solid phase and eluent (n-hexane, dichloromethane, dichloromethane–n-hexane (8:2 and 1:1, v/v) and dichloromethane–ethyl acetate (9:1, 8:2 and 7:3, v/v)). The best results were obtained using 0.5 g propolis, 1.0 g silica as dispersant sorbent, 1.0 g Florisil as clean-up sorbent,
and dichloromethane–ethyl acetate (9:1, v/v) as eluting solvent. The method was validated by analysis of propolis samples fortified at different concentration levels
(0.25 to 1.0 mg kg−1). Average recoveries (four replicates) ranged from 67% to 175% with relative standard deviation between 5.6% and 12.1%. Detection
and quantification limits ranged from 0.05 to 0.10 mg kg−1 and 0.15 to 0.25 mg kg−1 propolis, respectively. 相似文献
13.
A. N. Garg A. Kumar R. P. Choudhury 《Journal of Radioanalytical and Nuclear Chemistry》2007,271(2):481-488
A nondestructive NAA method based on the reaction 31P(n,γ)32P (T
1/2 = 14.23 d) has been developed where the product nucleus, a pure β-emitter with end point energy 1.71 MeV is measured by using
an end window G.M. counter and an Al filter of 27 mg·cm−2. 32P was identified by measuring E
β using Feather’s analysis and its half-life was found to be 15.3±0.2 days in standard reference materials (SRMs) and samples.
For most reference materials (RMs) from NIST (USA) and IAEA (Vienna), our values agree within ±5% of the certified values.
A variety of biological samples have also been analyzed and our values are in the range; medicinal herbs (n = 43), 0.29–5.23 mg/g; bhasmas (n = 19), 0.09–51.4 mg/g; vegetables (n = 8), 1.85–5.73 mg/g; lentils (n = 6), 2.1–5.5 mg/g; flours (n = 6), 1.3–3.3 mg/g; vegetarian diet (n = 5), 2.41–2.90 mg/g; fish (n = 43), 3.61–36.8 mg/g; human and animal milk (n = 6), 1.24–7.95 mg/g; commercial milk powders (n = 14), 2.76–11.9 mg/g; water from various sources (n = 14), 1–417 μg/l; human and animal blood (n = 9), 1.00–15.0 mg/g; cancerous and healthy breast tissue (n = 60), 1.00–8.63 mg/g; human hair (n = 43), 0.12–5.81 mg/g, where n is the number of samples analyzed. The method is simple, fast, and nondestructive and provides
data within ±5% error limit with a detection limit of 0.1 mg/g. 相似文献
14.
Monia Blibech Raoudha Ellouz Ghorbel Ines Fakhfakh Patricia Ntarima Katheleen Piens Abir Ben Bacha Semia Ellouz Chaabouni 《Applied biochemistry and biotechnology》2010,160(4):1227-1240
The highest β-mannanase activity was produced by Penicillium occitanis Pol6 on flour of carob seed, whereas starch-containing medium gave lower enzymes titles. The low molecular weight enzyme
was purified to homogeneity by ammonium sulfate precipitation, gel filtration, and ion-exchange chromatography procedures.
The purified β-mannanase (ManIII) has been identified as a glycoprotein (carbohydrate content 5%) with an apparent molecular
mass of 18 kDa. It was active at 40 °C and pH 4.0. It was stable for 30 min at 70 °C and has a broad pH stability (2.0–12.0).
ManIII showed K
m, V
max, and K
cat values of 17.94 mg/ml, 93.52 U/mg, and 28.13 s−1 with locust bean gum as substrate, respectively. It was inhibited by mannose with a K
I of 0.610−3 mg/ml. ManIII was activated by CuSO4 and CaCl2 (2.5 mM). However, in presence of 2.5 mM Co2+, its activity dropped to 60% of the initial activity. Both N-terminal and internal amino acid sequences of ManIII presented
no homology with mannanases of glycosides hydrolases. During incubation with locust bean gum and Ivory nut mannan, the enzyme
released mainly mannotetraose, mannotriose, and mannobiose. 相似文献
15.
D. Ertel 《Journal of Radioanalytical and Nuclear Chemistry》1969,2(3-4):205-209
By intensity measurements of the uranium and plutoniumL
α1-lines these elements can be determined simultaneously either in aqueous or in organic Purex process solutions. Thorium was
used as an internal standard. The sensitivity of the method is about 105 cpm/mg U, Pu/ml and the detection limits are around 2–3 μg U, Pu/ml. The analytical range extends from 0.003 mg U, Pu/ml
up to 10 mg U, Pu/ml. A time-saving routine procedure is described. Interferences detected at extreme U/Pu concentration ratios
are discussed and explained. 相似文献
16.
Weisheng Yue Xiaolin Li Jiangfeng Liu Yulan Li Guilin Zhang Yan Li 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(1):115-121
Due to the interesting anti-proliferative properties of gallium-thiosemicarbazone complexes, the production of [67Ga]labeled 2-acetylpyridine 4,4-dimethyl thiosemicarbazone (APTSM2) was investigated. The freshly prepared [67Ga]GaCl3 was mixed with 2-acetylpyridine 4,4-dimethyl thiosemicarbazone for 60 minutes at 90 °C to yield [67Ga]APTSM2 with a radiochemical yield of more than 98%. Radio-thin-layer-chromatography (RTLC) showed a radiochemical purity of more
than 99%. A specific activity of about 370–740 MBq/mmol (10–20 Ci/mmol) was obtained. The stability of the final product was
checked in the absence and presence of human serum at 37 °C. The partition coefficient of the final complex was also determined.
The biodistribution of the labeled compound in normal rats was compared with that of free Ga3+ cation up to 22 hours. 相似文献
17.
Jae Hyung Park Yong Woo Cho Yoen Ju Son Kwangmeyung Kim Hesson Chung Seo Young Jeong Kuiwon Choi Chong Rae Park Rang-Woon Park In-San Kim Ick Chan Kwon 《Colloid and polymer science》2006,284(7):763-770
An anthracycline drug, adriamycin, was chemically conjugated onto the backbone of glycol chitosan via an acid-labile cis-aconityl linkage. The physicochemical characteristics of the glycol chitosan–adriamycin (GC–ADR) conjugates were investigated by dynamic light scattering, atomic force microscopy, and fluorescence spectroscopy. The GC–ADR conjugates were capable of forming nano-sized self-aggregates in an aqueous medium, when the adriamycin content in the conjugate was in the range of 2.0–5.0 wt.%. The self-aggregates were spherical in shape, and had mean diameters of 238–304 nm, depending on the adriamycin content. The critical aggregation concentrations of the conjugates, estimated by the fluorescence quenching method, were as low as 1.0–2.5×10−2 mg/ml. The size of self-aggregates was not affected by the polymer concentration in the range from 50 to 2,000 μg/ml, and was maintained up to 8 days in phosphate-buffered saline (pH 7.4), indicating high colloidal stability. The release of adriamycin from self-aggregates was significantly dependent on the pH of the medium due to the cis-aconityl linkage; e.g., the amount of adriamycin released for 4 days was 7.3±0.3% at pH 7, whereas it was 29.3±1.9% at pH 4. The cell viability results demonstrated that free adriamycin shows more potent cytotoxicity than the conjugates, primarily attributed to the sustained release of adriamycin from self-aggregates. In conclusion, the self-aggregates, formed by GC–ADR conjugates, might be useful for the site-specific delivery of adriamycin in a sustained manner. 相似文献
18.
Barroso MF Paíga P Vaz MC Delerue-Matos C 《Analytical and bioanalytical chemistry》2005,383(5):880-885
The electrochemical behaviour of the pesticide metam (MT) at a glassy carbon working electrode (GCE) and at a hanging mercury
drop electrode (HMDE) was investigated. Different voltammetric techniques, including cyclic voltammetry (CV) and square wave
voltammetry (SWV), were used. An anodic peak (independent of pH) at +1.46 V vs AgCl/Ag was observed in MT aqueous solution
using the GCE. SWV calibration curves were plotted under optimized conditions (pH 2.5 and frequency 50 Hz), which showed a
linear response for 17–29 mg L−1. Electrochemical reduction was also explored, using the HMDE. A well defined cathodic peak was recorded at −0.72 V vs AgCl/Ag,
dependent on pH. After optimizing the operating conditions (pH 10.1, frequency 150 Hz, potential deposition −0.20 V for 10 s),
calibration curves was measured in the concentration range 2.5×10−1 to 1.0 mg L−1 using SWV. The electrochemical behaviour of this compound facilitated the development of a flow injection analysis (FIA)
system with amperometric detection for the quantification of MT in commercial formulations and spiked water samples. An assessment
of the optimal FIA conditions indicated that the best analytical results were obtained at a potential of +1.30 V, an injection
volume of 207 μL and an overall flow rate of 2.4 ml min−1. Real samples were analysed via calibration curves over the concentration range 1.3×10−2 to 1.3 mg L−1. Recoveries from the real samples (spiked waters and commercial formulations) were between 97.4 and 105.5%. The precision
of the proposed method was evaluated by assessing the relative standard deviation (RSD %) of ten consecutive determinations
of one sample (1.0 mg L−1), and the value obtained was 1.5%. 相似文献
19.
A column preconcentration method has been established for the spectrophotometric determination of traces of nitrite using
diazotization and coupling on an naphthalene-tetradecyldimethylbenzylammonium (TDBA)-iodide (I) adsorbent. Nitrite ion reacts
with sulfanilic acid (SA) in the pH range 1.8–3.0 for the SA-1-naphthol system and in the pH range 2.3–3.2 for the SA-1-naphthylamine-4-sulfonate
system (SA-NAS system) in hydrochloric acid medium to form water-soluble colourless diazonium cations. These cations were
coupled with 1-naphthol in the pH range 1.6–4.6 and with NAS in the pH range 2.6–5.0 to be retained on naphthalene-TDBA-I
packed in a column. The solid mass was dissolved from the column with 5 mL of dimethylformamide (DMF) and the absorbance measured
at 418 nm for the SA-1-naphthol system and at 485 nm for the SA-NAS system. The calibration curve was linear over the concentration
range 0.02–0.87 mg/L for SA-1-naphthol and 0.02–0.80 mg/L in the sample for SA-NAS. The molar absorptivity was calculated
to be 1.70 × l04 Lmol−1 cm−1 for SA-1-naphthol and 1.66 × l04 L mol−1 cm−1 for SA-NAS. The detection limits were found to be 0.014 and 0.016 mg/L for SA-1-naphthol and SA-NAS, respectively. The preconcentration
factors were 8 and 6 for SA-1-naphthol and SA-NAS, respectively. Replicate determinations of seven sample solutions containing
6.6 ug of nitrite for SA-1-naphthol and 5.3 ug of nitrite for SA-NAS gave mean absorbances of 0.486 and 0.382 with relative
standard deviations of 0.49 and 0.58%, respectively. Interferences due to various foreign ions have been studied and the method
has been applied to the determination of 27–65 μg/L levels of nitrite in natural waters. The recovery and relative standard
deviation for water samples were 98–102% and 0.49–0.58% for both systems.
Presented at the 29th Colloquium Spectroscopicum Internationale, Leipzig, Germany, 27 August –1 September 1995 相似文献
20.
Summary Colloidal plasma substitutes of chemically modified starch are used in surgery and in emergency medicine. Acetyl starch (ACS)
is a new plasma substitute based on an amylopectin acetic ester. Metabolic cleavage of the ACS ester substituents leads to
improved degradation and elimination of infused polymer. To determine the metabolic fate of ACS a rapid LC-method for ACS
quantitiation in blood samples was needed. For this purpose a size-exclusion chromatography (SEC) system with improved sensitivity
is outlined using a refractive index detector. The limit of detection is 0.005 mg mL−1. From 0.10–5.00 mg mL−1 a linear relationship (correlation coefficient R=0,9999) between the RI signal and ACS concentration is obtained. Recoveries
of ACS from blood plasma range 102.3–107.7% for ACS 200/0.5 (range 0.20–7.94 mg mL−1) and 103.0–111.4% for ACS 200/0.7 (range 0.19–9.33 mg mL−1). Only small differences between runs are obtained. In the inter assay test coeficients of variation of 1.8% and of 2.6%
respectively are obtained for ACS 200/0.5 and ACS 200/0.7. 相似文献