Correlation Between Endoscopic Macroscopic Type and Depth of Tumor Invasion for Superficial Adenocarcinoma of Esophagogastric Junction

Objective To develope a method of solvent demulsification dispersive liquid phase microextraction (SD-DLPME) based on ion association reaction coupled with graphite furnace atomic absorption spectroscopy (GFAAS) for detecting thallium in water samples. Methods Thallium ion in water samples was oxidized to Tl(Ⅲ) with bromine water, which reacted with Cl^- to form TlCl₄^-. The ionic associated compound with trioctylamine was obtained and extracted. DLPME was completed with ethanol as dispersive solvent. The separation of aqueous and organic phase was achieved by injecting into demulsification solvent without centrifugation. The extractant was collected and injected into GFAAS for analysis. With palladium colloid as matrix modifier, a two step drying and ashing temperature programming process was applied for high precision and sensitivity. Results The linear range was 0.05-2.0 μg/L, with a detection limit of 0.011 μg/L. The relative standard derivation (RSD) for detecting Tl in spiked water sample was 9.9%. The spiked recoveries of water samples ranged from 94.0% to 103.0%. Conclusion The method is simple, sensitive and suitable for batch analysis of Tl in water samples.