[Determination of bisphenol S in urine by vortex-assisted liquid-liquid microextraction with high performance liquid chromatography].

Objective: To establish a method for the determination of bisphenol S in urine using dispersive liquid-liquid microextraction (DLLME) coupled with high performance liquid chromatography (HPLC) . Methods: The acetonitrile, octanol were used as extraction solvent, dispersive solvent respectively, for the preconcentration of bisphenol S. The optimal extraction conditions were optimized by single factor rotations, and methodological performance index were tested. Results: The linear correlation coefficient of bisphenol S in the range of 0.0-160 µg/L is greater than 0.999. The detection limit of this method was 0.76 µg/L, and the recovery rates were 88.06%-103.81%. The intra-and inter-day precisions were 1.78%-2.85% and 2.65%-4.25%, respectively. Conclusion: The method is reliable and sensitive. It is suitable for the determination of bisphenol S in urine samples for occupational exposure populations and non-professional.

[Determination of nickel in urine by ultrasonic-assisted ionic liquid microextraction-graphite furnace atomic absorption spectrometry].

Objective: To set up a new method to determine the nickel of urine in urine using dispersive liquid-liquid microextraction (DLLME) coupled with graphite furnace atomic absorption spectrometry (GFAAS) . Methods: From September 2018 to September 2019, the methanol, pyrrolidine dithiocarbamate and ionic liquid 1-hexyl-3-methyl-imidazolium hexafluorophosphate were used as dispersive solvent, the chelating agent and extraction solvent for the preconcentration of nickel, respectively. After adding into buffer solution of pH 9, ultrasonic dissolving for 10 minutes, centrifugal separation and then discarding the supernatant, the precipitate was saved. Dissolving the precipitate by methanol, mixing thoroughly on a vortex mixer, the 15 µl of the mixed solution was used for determination by graphite furnace atomic absorption spectrometry. Results: The linear correlation coefficient of urine nickel concentration in the range of 2.0-10.0 µg/L, r=0.999, with the detection limitation of 0.43 µg/L. The recovery rate and the relative standard deviations were 95.6%-103.7% and 2.53%-4.82%, respectively. Conclusion: The method, which has low detection limit, high recovery rate and good precision, is suitable for the determination of nickel in urine for the occupational populations exposure to nickel and non-occupational exposure.

[Recurrent bleeding following the renal artery embolization treating post-percutaneous nephrolithotomy hemorrhage: causes and countermeasure].

Objective: To explore the causes and countermeasure in recurrent bleeding following the selective renal artery embolization treating post-percutaneous nephrolithotomy hemorrhage. Methods: A total of 334 patients of severe renal hemorrhage associated with percutaneous nephrolithotomy (PCNL) from March 2011 to April 2015 were analyzed retrospectively.All the patients underwent super selective angiography and renal artery embolization.The causes of recurrent hemorrhage were analyzed and principles for diagnosis and embolization were studied. Results: The initial embolization was performed in 329 cases hospitalized in the First Affiliated Hospital of Guangzhou Medical University and 318 cases were successfully stopped bleeding with a hemostatic rate of 96.7 %(318/329). Of total 334 consecutive cases, there were 16 cases of recurrent renal hemorrhage, 11 cases were initially embolized in this hospital, and otherwise the other 5 cases were in other hospitals. Causes of recurrent hemorrhage were missed embolization of tiny pseudoaneurysm (n=12), and two cases of 12, the tiny pseudoaneurysm were feeding by accessory renal arteries, undetected arteriovenous fistula(n=2), recanalization of the embolized arteries (n=2). Conclusion: The causes of recurrent bleeding fallowing the initial selective renal artery embolization treating post-percutaneous nephrolithotomy hemorrhage are varied, and missed embolization of tiny pseudoaneurysm is the major cause of unsuccessful initial renal artery embolization. To strengthen the understanding of tiny pseudoaneurysm is helpful to improve the success rate of hemostasis.