Determination of the Unconjugated Forms of Benzophenone-3 and Benzophenone-4 in Urine by Solid-Phase Extraction Coupled to a Liquid Chromatographic System with UV/Vis Detection by Using Automated Sequential Injection Analysis

2013 ◽  
pp. 83-102
Author(s):  
Zacarías León González
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Sequential Injection Analysis ◽  
Phase Extraction ◽  
Sequential Injection ◽  
Chromatographic System ◽  
Liquid Chromatographic

scholarly journals Automated Online Solid-Phase Extraction Coupled with Sequential Injection-HPLC-EC System for the Determination of Sulfonamides in Shrimp

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Pimkwan Chantarateepra ◽  
Weena Siangproh ◽  
Shoji Motomizu ◽  
Orawon Chailapakul
Keyword(s):  
Solid Phase Extraction ◽  
High Performance ◽  
Solid Phase ◽  
Sequential Injection Analysis ◽  
Phase Extraction ◽  
Sequential Injection ◽  
Elution Time ◽  
Online Solid Phase Extraction ◽  
Relative Standard

The use of fully automated online solid-phase extraction (SPE) coupled with sequential injection analysis, high-performance liquid chromatography (HPLC), and electrochemical detection (EC) for the separation and determination of sulfonamides has been developed. A homemade microcolumn SPE system coupled with sequential injection analysis (SIA) was used to automate the sample cleanup and extraction of sulfonamides. The optimal flow rate of sample loading and elution was found to be 10 μL/s, and optimal elution time of zone was 20–24 s. Under the optimal conditions, a linear relationship between peak area and sulfonamide concentrations was obtained in the range of 0.01–8.0 μg mL−1. Detection limits for seven sulfonamides were between 1.2 ng mL−1and 11.2 ng mL−1. The proposed method has been applied for the determination of sulfonamides in shrimp. Recoveries in the range of 84–107% and relative standard deviations (RSDs) below 6.5% for intraday and 13% for inter-day were received for three concentration levels of spiking. The results showed that the present method was simple, rapid, accurate and highly sensitive for the determination of sulfonamides.

scholarly journals Application of a Mixed-Mode Solid-Phase Extraction and Cleanup Procedure for LC/MS Determination of Thiabendazole and Carbendazim in Apple Juice

2001 ◽  
Vol 84 (5) ◽  
pp. 1608-1614 ◽  
Author(s):  
Michael S Young ◽  
Michael F Early ◽  
Claude R Mallet ◽  
Jim Krol
Keyword(s):  
Solid Phase Extraction ◽  
Mixed Mode ◽  
Apple Juice ◽  
Solid Phase ◽  
Ionization Mass ◽  
Phase Extraction ◽  
Cleanup Procedure ◽  
Sample Preparation Procedure ◽  
Liquid Chromatographic

Abstract Recently, a mixed-mode solid-phase extraction (SPE) procedure was developed for rapid extraction and cleanup for determination of the fungicides thiabendazole and carbendazim in various fruit juices. This paper reports the application of that sample preparation procedure to the liquid chromatographic/mass spectrometric determination of these fungicides in apple juice with detection by positive electrospray ionization mass spectrometry (ESI/MS). Response was linear for sample concentrations from 2 to 500 μg/L (ppb). Recoveries averaged 74% (9% RSD) for carbendazim and 93% (9% RSD) for thiabendazole. After SPE cleanup, no matrix supression was observed for the ESI+ response for either compound studied. The method was applied to the analysis of incurred residues in 4 store-bought apple juices; carbendazim levels ranged from 10 to 70 μg/L and thiabendazole levels ranged from less than 2 to 130 μg/L.

Liquid Chromatographic Screening Method for Fluorescent Derivatives of Chlorophenoxy Acid Herbicides in Water

1992 ◽  
Vol 75 (4) ◽  
pp. 720-724 ◽  
Author(s):  
Toshinari Suzuki ◽  
Satoru Watanabe
Keyword(s):  
Solid Phase Extraction ◽  
Water Samples ◽  
Solid Phase ◽  
Screening Method ◽  
Ethyl Esters ◽  
Separate Determination ◽  
Phase Extraction ◽  
Liquid Chromatographic ◽  
Acid Herbicides

Abstract A liquid chromatographic method for screening 9 chlorophenoxy acids (2,4-D; 2,4-DP; 2,4-DB; MCPA; MCPP; MCPB; 2,4,5-T; 2,4,5-TP; and 2,4,5-TB) and their ethyl esters in ground- and tap water is presented. The water samples are acidified and subjected to either liquid-liquid or solid-phase extraction. The extracts obtained are saponified in 0.03N NaOH-50% methanol (1+1) and the acidic compounds are re-extracted with ethyl acetate-n-hexane (8 + 2) after acidification and derivatized with 9- anthryldiazomethane. Derivatized compounds are analyzed using reversed-phase column chromatography with fluorescence detection (excitation, 365 nm; emission, 412 nm). Recoveries of analytes from 20 mL water samples were greater than 90%, and the average coefficient of variation was within 5.0% at 0.5 ppb for both extraction methods. These methods are simple and useful for the determination of small amounts of chlorophenoxy herbicides. Solid-phase extraction is suitable for screening a large number of samples simultaneously, and liquid extraction for separate determination of the acids and ethyl esters of the herbicides was improved by introducing a saponification step.

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