Sensitive Determination of Total Microcystins in Water by Derivatization-Gaschromatography-Mass Spectrometry

2014 ◽  
Vol 955-959 ◽  
pp. 1321-1325
Author(s):  
Hong Ping Pu ◽  
Qian Cai ◽  
Xue Jun Pan
Keyword(s):  
Mass Spectrometry ◽  
Drinking Water ◽  
Detection Limit ◽  
Method Development ◽  
Freshwater Lakes ◽  
Molecular Weights ◽  
Sensitive Determination ◽  
Phenylbutyric Acid ◽  
Sensitive Method

The aim of the method development in this paper was to tackle the problems with the erythro-2-methyl-3-methoxy-4-phenylbutyric acid (MMPB) methodology: the rather laborious workflow and the loss of material during different steps of the method. In the optimised workflow, The detection limit of MMPB was 0.01 μg/L. Supposing the average of molecular weights of microcystins variants are 1000, the value of the detection limit is equivalent to 0.05 μg/L of microcystins. These results indicated that this method is the most sensitive method for determination of total microcystins, and it could be applied to the monitoring of microcystins in drinking water, reservoirs and freshwater lakes.

Colorimetric Determination of Fluoride in Drinking Groundwater using a Polymeric Zirconium Complex of 5-(2-Carboxyphenylazo)-8-Hydroxyquinoline

2013 ◽  
Vol 12 (7) ◽  
pp. 460-465
Author(s):  
Sameer Amereih ◽  
Zaher Barghouthi ◽  
Lamees Majjiad
Keyword(s):  
Drinking Water ◽  
Detection Limit ◽  
Complex Formation ◽  
Molar Absorptivity ◽  
Colorimetric Determination ◽  
Zirconium Complex ◽  
Reliable Determination ◽  
Percentage Recovery ◽  
Quantitation Limit

A sensitive colorimetric determination of fluoride in drinking water has been developed using a polymeric zirconium complex of 5-(2-Carboxyphenylazo)-8-Hydroxyquinoline as fluoride reagents. The method allowed a reliable determination of fluoride in range of (0.0-1.5) mg L-1. The molar absorptivity of the complex formation is 7695 ± 27 L mol-1 cm-1 at 460 nm. The sensitivity, detection limit, quantitation limit, and percentage recovery for 1.0 mg L-1 fluoride for the proposed method were found to be 0.353 ± 0.013 μg mL-1, 0.1 mg L-1, 0.3 mg L-1, and 101.7 ± 4.1, respectively.

Alcohol Determination by HPLC with Postcolumn Derivatization Based on the Thiosulfate-catalyzed Reaction of Alcohols and Cerium(IV) and Fluorescence Detection of Cerium(III)

2020 ◽  
Vol 16 ◽  
Author(s):  
Ikko Mikami ◽  
Eri Shibayama ◽  
Kengo Takagi
Keyword(s):  
Detection Limit ◽  
Fluorescence Detection ◽  
Reaction Rate ◽  
Detection Method ◽  
Fluorescence Detector ◽  
Reaction Solution ◽  
Optimum Detection ◽  
Postcolumn Derivatization ◽  
Sensitive Method

Background: Determination of a reducing substance based on the reaction between Ce(IV) and a reducing substance and fluorescence detection of Ce(III) generated has been reported as a selective and sensitive method. However, this method could not be applied to the determination of alcohol due to the low reaction rate of alcohol and Ce(IV). Objective: We found that thiosulfate catalytically enhanced reaction of alcohols (such as, methanol, ethanol, and propanol) and Ce(IV). Utilizing this effect, we developed a new method for the determination of alcohols. Results: In the presence of thiosulfate, an increase in fluorescence intensity was detected by injecting alcohol at concentrations of several millimolar, whereas it was not observed even at the concentration of 10% v/v (2 M for ethanol) in the absence of thiosulfate. The optimum detection conditions were determined to be 4.0 mM Ce(IV) sulfate and 0.50 mM thiosulfate, and the detection limit (S/N = 3) of ethanol under these conditions was 1 mM. In the calibration curves, changes in the slope were observed when the alcohol concentrations were approximately 10–25 mM. Using a thiosulfate solution containing ethanol as the reaction solution, a calibration curve without any change in slope was obtained, although the concentration of ethanol at the detection limit increased. The alcohols in the liquor and fuel were successfully analyzed using the proposed detection method as a postcolumn reaction. Conclusion: This new alcohol detection method using a versatile fluorescence detector can be applied to the postcolumn reaction of HPLC omitting need of time-consuming pretreatment processes.

scholarly journals The pathway through LC-MS method development: in-house or ready-to-use kit-based methods?

2020 ◽  
Vol 58 (6) ◽  
pp. 1002-1009 ◽  
Author(s):  
Caroline Le Goff ◽  
Jordi Farre-Segura ◽  
Violeta Stojkovic ◽  
Patrice Dufour ◽  
Stéphanie Peeters ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Method Development ◽  
Clinical Laboratory ◽  
Cross Reactivity ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

AbstractHistorically, the determination of low concentration analytes was initially made possible by the development of rapid and easy-to-perform immunoassays (IAs). Unfortunately, typical problems inherent to IA technologies rapidly appeared (e.g. elevated cost, cross-reactivity, lot-to-lot variability, etc.). In turn, liquid chromatography tandem mass spectrometry (LC-MS/MS) methods are sensitive and specific enough for such analyses. Therefore, they would seem to be the most promising candidates to replace IAs. There are two main choices when implementing a new LC-MS/MS method in a clinical laboratory: (1) Developing an in-house method or (2) purchasing ready-to-use kits. In this paper, we discuss some of the respective advantages, disadvantages and mandatory requirements of each choice. Additionally, we also share our experiences when developing an in-house method for cortisol determination and the implementation of an “ready-to-use” (RTU) kit for steroids analysis.

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