scholarly journals Determination of epinephrine by the Briggs-Rauscher oscillating system using non-equilibrium stationary state

2012 ◽  
Vol 77 (1) ◽  
pp. 95-104 ◽  
Author(s):  
Jinzhang Gao ◽  
Yanjun Liu ◽  
Jie Ren ◽  
Xiaoli Zhang ◽  
Li Ming ◽  
...  
Keyword(s):  
Detection Limit ◽  
Stationary State ◽  
Lower Detection Limit ◽  
Highly Sensitive ◽  
Lower Detection ◽  
Oscillating Reaction ◽  
The Difference ◽  
Foreign Species ◽  
Non Equilibrium

A highly sensitive method for the determination of epinephrine was proposed, which was based on the perturbation of epinephrine to Briggs-Rauscher oscillating system involving malonic acid, Mn2+, H+, IO3 - and H2O2 at non-equilibrium stationary state. The concentration of KIO3 was chosen as a control parameter to find the bifurcation point in this paper. Results showed that a well linear relationship between the difference of potential and the negative logarithm concentrations of epinephrine existed in the range of 1.1?10-7?5.2?10-9 mol L-1 with a lower detection limit of 6.8?10-10mol L-1 and a correlation coefficient of 0.9974. Compared to the classical oscillating reaction, this method has a lower detection limit and wider linear range. The effects of some foreign species, which may possibly be existed with epinephrine, on determination were also investigated. The proposed method has been successfully used to determine the epinephrine both in the serum and adrenaline hydrochloride injection.

Improved Spectrophotometric Determination of Cyclopiazonic Acid in Poultry Feed and Corn

1990 ◽  
Vol 73 (2) ◽  
pp. 257-259 ◽  
Author(s):  
Ivan Chang-Yen ◽  
Keshore Bidasee
Keyword(s):  
Detection Limit ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Cyclopiazonic Acid ◽  
Poultry Feed ◽  
Reaction Conditions ◽  
Lower Detection Limit ◽  
Lower Detection ◽  
Feed Samples

Abstract An improved visible spectrophotometric method has been developed for cyclopiazonic acid in poultry feed and corn. The method Is based on the reaction of cyclopiazonic acid with Ehrlich reagent and detection at 580 nm. Reaction conditions were optimized with respect to reaction and measurement times and acid and Ehrlich reagent concentrations. Calibration curves were linear from 1 to 20 μg cyclopiazonic acid in 3 mL Ehrlich reagent, with a lower detection limit of 0.08 mg/kg for 50 g samples of poultry feed and corn. Recoveries from 50 g samples of poultry feed spiked with cyclopiazonic ranging from 0.16 to 1.20 mg/kg averaged 93.8%. Moldy corn and poultry feed samples analyzed by this method contained between 1 and 4 mg/kg cyclopiazonic acid.

Analysis of Tri-aryl Phosphate Esters and the Determination of Imol S-140 in Fish Tissue and Water Samples by Gas Chromatography

1975 ◽  
Vol 32 (4) ◽  
pp. 457-460 ◽  
Author(s):  
Derek A. J. Murray
Keyword(s):  
Gas Chromatography ◽  
Detection Limit ◽  
Water Samples ◽  
Fish Tissue ◽  
Phosphate Esters ◽  
Lower Detection Limit ◽  
Lower Detection ◽  
Trimethylsilyl Derivatives ◽  
The Individual

This report describes a method for the analysis of tri-aryl phosphate esters used commercially as lubricants. In a fish toxicity study, Imol S-140 (tri-tolyl phosphate) was extracted from fish tissue and water samples, hydrolyzed, and the individual phenols measured by gas chromatography as the trimethylsilyl derivatives. The lower detection limit was about 3 ppm of Imol in wet fish tissue.

Differential assay of zidovudine and its glucuronide metabolite in serum and urine with a radioimmunoassay kit

1990 ◽  
Vol 36 (6) ◽  
pp. 897-900 ◽  
Author(s):  
S M Tadepalli ◽  
L Puckett ◽  
S Jeal ◽  
L Kanics ◽  
R P Quinn
Keyword(s):  
Inhibitory Concentration ◽  
Serum Samples ◽  
Lower Detection Limit ◽  
Coefficients Of Variation ◽  
Lower Detection ◽  
Before And After ◽  
The Difference ◽  
Glucuronide Metabolite ◽  
Serum And Urine

Abstract We developed an ancillary procedure for the ZDV-Trac RIA (Incstar) to allow simultaneous determination of both zidovudine (3'-azido-3'-deoxythymidine, ZDV, AZT, Retrovir) and its metabolite, the glucuronide of ZDV (3'-azido-3'-deoxy-5'-O-beta-D-glucopyranuronosylthymidine, ZDVG, GAZT), in human serum and urine. Using the ZDV-Trac RIA, we measured ZDV concentrations before and after ZDVG in samples was hydrolyzed to ZDV by beta-glucuronidase (EC 3.2.1.31); ZDVG concentration was calculated as the difference between the two results. This method enables rapid evaluation of a large number of samples with a total turn-around time of 6 h. The lower detection limit of the RIA was 0.27 micrograms/L; the measurements varied linearly with ZDV concentrations from 0.27 to 217 micrograms/L, with the 50% inhibitory concentration being approximately 10 micrograms/L. Analytical recoveries of inhouse serum and urine controls for both ZDV and ZDVG exceeded 90%. Coefficients of variation (CVs) of serum controls were less than 6% for ZDV and less than 11% for ZDVG; for urine controls, CVs for both ZDV and ZDVG were less than 6%. Results for ZDVG concentrations obtained by HPLC and by the ZDV-Trac RIA system compared well: r = 0.978, slope 1.0, for serum samples, and r = 0.993, slope 1.09, for urine samples.

Determination of Residual Acrylamide Monomer in Medical Polyacrylamide Hydrogel by HPLC-SPE

2005 ◽  
Vol 288-289 ◽  
pp. 405-408
Author(s):  
Zi Yi Wan ◽  
Ting Fei Xi ◽  
P. Zhao ◽  
Y. Sun ◽  
Z.G. Feng
Keyword(s):  
Detection Limit ◽  
Solid Phase ◽  
Polyacrylamide Hydrogel ◽  
Simple Method ◽  
Lower Detection Limit ◽  
Response Range ◽  
Coefficients Of Variation ◽  
Lower Detection ◽  
Linear Response Range

The polyacrylamide hydrogel (PAMG) has been used in cosmetology in China, Ukraine and Russia since 1990s. Because the monomer acrylamide(AM) used to produce PAMG has been implicated as a potential mutagen and reproductive toxicant[1,2], it is important to accurately determine the amount of residual AM monomer in the PAMG. In this study, a quick, practical and simple method to determine AM is presented with respect to the hydrogel. AM is analysed quantitatively by ODS-3 column with ultraviolet (UV) absorbance detector. AM is separated from interferential component with an aqueous solution of 0.9%NaCl (NS) adjusted at pH~3.7 using hydrochloric acid and then detected at a UV wavelength of 210 nm. The results show that ODS-3 is effective approach for quantifying AM concentrations in PAMG. This method has a lower detection limit of 0.003µg/ml and a linear response range of 0.003 and 0.9 µg/ml (depending on the range required for analysis). Precision studies give coefficients of variation of <3.2%(n=5) for 0.003µg/ml. The recoveries for this method are greater than 90%. When AM content in PAMG is lower than the detection limit of this method, SPE (solid phase extraction) could be used to concentrate AM. In the case, C18 cartridge is used. And the recoveries are about 70% for SPE when AM concentration is lower than ppb.

scholarly journals Determination of p-nitroaniline by the tartrate-acetone-Mn2+-KBrO3-H2SO4 double organic substrate oscillating system using non-equilibrium stationary state

2009 ◽  
Vol 7 (3) ◽  
pp. 298-302 ◽  
Author(s):  
Jinzhang Gao ◽  
Jing Liu ◽  
Jie Ren ◽  
Xiuli Niu ◽  
Yingying Zhang ◽  
...  
Keyword(s):  
Detection Limit ◽  
Linear Relationship ◽  
Bifurcation Point ◽  
Convenient Method ◽  
Control Parameter ◽  
Organic Substrate ◽  
Optimum Conditions ◽  
Lower Detection Limit ◽  
Lower Detection

AbstractThis paper described the determination of p-nitroaniline in a double organic substrate oscillating system of tartrate-acetone-Mn2+-KBrO3-H2SO4. Under the optimum conditions, temperature was chosen as a control parameter to design the bifurcation point and proposed a convenient method for determination of p-nitroaniline. Results showed that the system consisting of 3.5 mL 0.06 mol L−1 tartrate, 4.0 mL 0.7 mol L−1 H2SO4, 1.5 mL 1.5×10−4 mol L−1 MnSO4, 4.0 mL 0.4 mol L−1 acetone and 7.0 mL 0.05 mol L−1 KBrO3 was very sensitive to the surrounding at 33.5°C. A good linear relationship between the potential difference and the negative logarithm concentration of p-nitroaniline was obtained to be in the range of 2.50×10−7∼3.75×10−5 mol L−1 with a lower detection limit of 2.50×10−8 mol L−1.

Determination of Ethylene Oxide and Ethylene Chlorohydrin in Plastic and Rubber Surgical Equipment Sterilized with Ethylene Oxide

1970 ◽  
Vol 53 (2) ◽  
pp. 263-267
Author(s):  
Daniel J Brown
Keyword(s):  
Detection Limit ◽  
Ethylene Oxide ◽  
Chromatographic Analysis ◽  
Ethylene Chlorohydrin ◽  
Surgical Equipment ◽  
Lower Detection Limit ◽  
Lower Detection ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic

Abstract A method is presented for the determination of ethylene chlorohydrin and ethylene oxide residues in plastic and rubber surgical equipment. Samples are extracted with p-xylene and the desired constituents are isolated by column chromatography. Ethylene oxide is converted to ethylene chlorohydrin on a Celite column. Sweep co-distillation is then employed for further purification, if necessary, before gas-liquid chromatographic analysis. The lower detection limit is approximately 25 ng. Recoveries of 3.5’50 ppm chlorohydrin from 20’35 g samples range from 64 to 100%, depending on the absorbing capacity of the material being analyzed and the condition of the adsorbent.

scholarly journals Multiple Fluorescent Labeling of Silica Nanoparticles with Lanthanide Chelates for Highly Sensitive Time-Resolved Immunofluorometric Assays

2007 ◽  
Vol 53 (8) ◽  
pp. 1503-1510 ◽  
Author(s):  
Ye Xu ◽  
Qingge Li
Keyword(s):  
Detection Limit ◽  
Hepatitis B ◽  
Silica Nanoparticles ◽  
Fluorescent Labeling ◽  
Time Resolved ◽  
Robust Detection ◽  
Lower Detection Limit ◽  
Lanthanide Chelates ◽  
Highly Sensitive ◽  
Lower Detection

Abstract Background: Time-resolved immunofluorometric assays (TrIFA) using lanthanide-labeled nanoparticles have greatly increased the sensitivity of immunoassays. Current labeling strategies, however, use either physical doping of lanthanide chelates into preformed nanoparticles or covalent linking of lanthanide chelates to precursors used for making nanoparticles; both these strategies have drawbacks. Methods: Luminescent Eu(III) and Tb(III) chelates were covalently coated on the surface of preformed silica nanoparticles to which detection antibodies or bridging proteins for antibody binding were conjugated. We used the resulting conjugates in TrIFA for detection of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg), both individually and simultaneously. We compared the results of the newly established method with results of an ELISA for serum samples. Positive samples identified by TrIFA but not by ELISA were confirmed by additional assays, including real-time PCR detection of viral DNA. Results: The prepared nanoparticle conjugates were homogeneous in size, at ∼55 (5) nm in diameter [mean (SD)], were stable for long-time storage (&gt;2 years), and contained more chelates [6.86 × 105 for Eu(III), 4.73 × 104 for Tb(III)] per nanoparticle than particles made as previously reported. The TrIFA established for HBsAg had a comparable or lower detection limit (0.0092 μg/L) than existing nanoparticle-based TrIFA or ELISA. The TrIFA for HBeAg had a much lower detection limit [10.0 National Centre Unit (NCU)/L] than ELISA and detected HBeAg in 5 samples missed by the ELISA method. Simultaneous TrIFA for both HBsAg and HBeAg was achieved with detection limits (0.033 μg/L for HBsAg and 27.0 NCU/L for HBeAg) close to those of the individual assays. Conclusions: Covalent surface labeling of silica nanoparticles with lanthanide chelates provides good fluorescent labels that can be used in TrIFA for highly sensitive and robust detection of clinical targets.

Determination of serum retinol (vitamin A) by high-speed liquid chromatography.

1976 ◽  
Vol 22 (10) ◽  
pp. 1593-1595 ◽  
Author(s):  
M G De Ruyter ◽  
A P De Leenheer
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Vitamin A ◽  
High Speed ◽  
Serum Retinol ◽  
Lower Detection Limit ◽  
Serum Pool ◽  
Lower Detection ◽  
Liquid Chromatographic

Abstract We report a fast and simple high-speed liquid-chromatographic assay for serum retinol. Only 100 mul of serum is required. The lower detection limit is 50 mug/liter; linearity was demonstrated up to 1.50 mg/liter. On analyzing a serum pool eight times, a CV of 2.5% was obtained. Values by this method are compared with results obtained by a flurometric method [Clin. Chem. 16, 766(1970)].

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