Experimental determination of the lower detection limit of a CNC by observation of the coagulation of H2SO4 nuclei

1975 ◽  
Vol 6 (6) ◽  
pp. 490
1990 ◽  
Vol 73 (2) ◽  
pp. 257-259 ◽  
Author(s):  
Ivan Chang-Yen ◽  
Keshore Bidasee

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.


2012 ◽  
Vol 77 (1) ◽  
pp. 95-104 ◽  
Author(s):  
Jinzhang Gao ◽  
Yanjun Liu ◽  
Jie Ren ◽  
Xiaoli Zhang ◽  
Li Ming ◽  
...  

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.


1975 ◽  
Vol 32 (4) ◽  
pp. 457-460 ◽  
Author(s):  
Derek A. J. Murray

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.


2005 ◽  
Vol 288-289 ◽  
pp. 405-408
Author(s):  
Zi Yi Wan ◽  
Ting Fei Xi ◽  
P. Zhao ◽  
Y. Sun ◽  
Z.G. Feng

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.


2009 ◽  
Vol 7 (3) ◽  
pp. 298-302 ◽  
Author(s):  
Jinzhang Gao ◽  
Jing Liu ◽  
Jie Ren ◽  
Xiuli Niu ◽  
Yingying Zhang ◽  
...  

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.


1970 ◽  
Vol 53 (2) ◽  
pp. 263-267
Author(s):  
Daniel J Brown

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.


1976 ◽  
Vol 22 (10) ◽  
pp. 1593-1595 ◽  
Author(s):  
M G De Ruyter ◽  
A P De Leenheer

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)].


2021 ◽  
Author(s):  
Yu Liu ◽  
Yan Wang ◽  
Xiao-Sa Zhang ◽  
Yu-Shu Sheng ◽  
Wen-Ze Li ◽  
...  

A Zn-CP exhibits remarkable fluorescence behaviours and stability in a wide range of pH values. It can become an outstanding candidate in the selective sensing of Fe3+, Mg2+, Cr2O72−, MnO4−, NB and NM at a lower detection limit.


1974 ◽  
Vol 20 (9) ◽  
pp. 1181-1186 ◽  
Author(s):  
Jorge Lizana ◽  
Kristoffer Hellsing

Abstract A manual immunonephelometric method for proteins has been developed by using an ordinary fluorometer as a nephelometer. By applying the enhancing effect of polyethylene glycol (av mol wt, 6000) on the immunological reaction, albumin and fibrinogen were quantitated after a 10-min reaction time. Under the present conditions the sensitivity was increased and thus antiserum consumption was decreased. The reaction conditions were carefully studied with respect to optimal time and concentration of the reactants. The precision of the method was 2.6-3.6% (CV). The lower detection limit in the albumin-antialbumin system was 0.1 mg/liter. Comparative studies showed a correlation coefficient of 0.991 with an automated immunonephelometric method for urinary albumin, and of 0.908 with a thrombin clottable method for plasma fibrinogen. We especially suggest use of this manual immunonephelometric method where small series of samples are to be analyzed.


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