Dual-wavelength dual-indicator catalytic kinetic spectrophotometry for determination of trace Ru(Ⅲ)

A new dual-wavelength dual-indicator catalytic kinetic spectrophotometric method for the determination of trace Ru(III)was studied.This method was based on Ru(III)-catalyzing oxidation of Arsenazo I and indigo carmine by potassium bromate in sulfuric acid.The absorbances of the catalytic and noncatalytic systems were measured at 510 and610 nm,respectively.Under the optimum conditions,the linear range of determination is 0–0.12 lgáml-1and the detection limit is 1.21 9 10-4lgáml-1.The method was applied for the determination of trace Ru(III)in ore samples with satisfactory results.

Spectrophotometric Determination of Trace Amounts of Vanadium(Ⅴ) by Means of Its Catalytic Effect on Oxidation of Azomethine-H by Bromate

A new selective and sensitive kinetic method for determination of trace amounts of vanadium(Ⅴ) (0.5～40ng/ml) based on its catalytic effect on the oxidation of azomethine H by bromate at pH 4.2 and 25 ℃ was reported and its reaction mechanism was studied.The reaction was monitored spectrophotometrically by measuring the increase in absorbance of oxidation product of azomethine H at 436 nm after a fixed time ( 5 min ).The detection limit of the method is down to 2.0×10 -10 g/ml and the relative standard deviation (RSD) for 30 ng/ml of V(Ⅴ) is 0.26 % ( n =6). The effect of foreign ions on V(Ⅴ) determination was also discussed,and the method is mostly free from interferences of other ions.The proposed method was successfully applied to the determination of trace amounts of vanadium in water samples.

Right time to detect urine iodine during papillary thyroid carcinoma diagnosis and treatment:A case report

BACKGROUND This is the first documentation of a spontaneous and nonspecific chemical reaction of an iodinated contrast media with ammonium persulfate used in As3+-Ce4+catalytic spectrophotometry for urine iodine concentration(UIC)detection.CASE SUMMARY We herein report an incidental case who had a dual source computed tomography examination for papillary thyroid carcinoma diagnosis.Serial spot urine specimens were collected during her hospitalization and were measured by As3+-Ce4+catalytic spectrophotometry on a Beckman Coulter AU5800.The reacted solutions were“brownish”,and the results showed extremely high iodine concentrations despite serial dilutions.The patient claimed no dietary habit of iodized salt or iodine-containing medical history,which strongly pointed to iodinated contrast media(ICM)via intravenous injection.Even with 0.01%ICM,its interruption is still profound on the desired urine iodine reaction with ammonium persulfate,leading to inaccurate UIC and possibly inappropriate treatment.CONCLUSION The following laboratory suggestions should be considered:(1)As3+-Ce4+catalytic spectrophotometry is only suitable for UIC measurement after confirmed ICM renal clearance;(2)A mass spectrometry-based method can be applied as an alternative during the ICM clearance period;and(3)The UIC baseline can be confirmed after ICM injection by consecutive detection for at least 2 mo.

Catalytic kinetic spectrophotometric determination of cerium

A new procedure for the determination of cerium was established using the catalytic effect of Ce(IV) on the oxidation of tribromoarsenazo(TB-ASA) by potassium bromate.In 0.080 mol/L sulfuric acid medium,the maximum absorption peak of Ce(IV)-(TB-ASA)-KBrO3 system is at 510 nm.The amount of Ce(IV) and the difference of absorbance(△A) showed a good linear relationship over the range of 5.7×10-8-5.1×10-7 mol/L.The regression equation is △A=2.3×10-11 C(C:mol/L)+0.0196,with a regression coefficient of 0.9914 at t...