A new method for screening and determination of diuretics by on‐line CE‐ESI‐MS

Abstract

A rapid, high-resolution and effective new method for analyzing 12 diuretics by CE-ESI-MS was established in this paper. Ten diuretics (except two neutral compounds) could be fast separated by CE with a DAD at 214 nm with a 20 kV voltage within 6 min, using a 50 microm id and 48.5 cm effective length uncoated fused-silica capillary in a 40 mM ammonium formate buffer (pH 9.40). CE was coupled to the mass spectrometer applying an orthogonal electrospray interface with a triple-tube sheath liquid arrangement. The sheath liquid was composed of isopropanol-water (1:1 v/v) containing 30 mM acetic acid with a flow rate of 4 microL/min. Mass spectrum was employed in the positive mode and both full scan mode and SIM scan mode were utilized. All 12 diuretics could be detected and confirmed by MS in a single analysis. Under optimized conditions, LODs for the 12 diuretics were in the range of 0.13-2.7 micromol/L at an S/N of 3, and the correlation coefficients R(2 )were between 0.9921 and 0.9978. The RDSs (n = 5) of the method was 0.24-0.94 % for migration times and 1.6-8.8 % for peak areas. The recoveries of spiked samples of 12 diuretics were between 72.4% and 118%. The real urine samples were injected directly for analysis, with only simple filtration through a 0.22 microm membrane filter in order to remove solid particles, which may cause capillary blockage. Based on the migration times and characteristic ions, the diuretics in urine samples were detected successfully. This CE-ESI-MS method for analyzing diuretics will hopefully be applied to doping control.

Electrochemical Oxidation of Metolazone at a Glassy Carbon Electrode

“…In addition, sodium cations and chloride anions may also affect the renal readsorption and excretion of potassium, calcium, magnesium and other ions. Some diuretics increase urinary potassium excretion and can cause hypokalemia in patients treated with these medications for prolonged times [1,2].…”

“…Based on the effect of diuresis, diuretics can also be classified into high-efficiency diuretics (such as loop diuretics), medium-efficiency diuretics (such as thiazides and related compounds) and low-efficiency diuretics (such as potassium-sparing diuretics and carbonic anhydrase inhibitors) [1].…”

CE at the omics level: Towards systems biology – An update

“…Agilent has produced a CE-MS system (an Agilent 3D CE system coupled to an Agilent 1100 series LC/MSD via an electrospray API interface) that is controlled by only one software program [6][7][8][9][10], whereas other CE-MS systems usually consist of two different instruments joined by an interface. For example, a Beckman and/or Agilent CE coupled with a Thermo Finnigan and/or Bruker MS through an ESI interface [11][12][13] are both operated by two different software programs.…”

Eletroforese capilar acoplada à espectrometria de massas (CE-MS): vinte anos de desenvolvimento

“…Um avanço no desenho da interface ESI com líquido coaxial para o formato ortogonal, isto é, a 90° com relação ao eixo do espectrô-metro, 52 ou para o formato excêntrico, isto é, alinhado com o eixo do espectrômetro 53 porém não centralizado, introduziu uma maior flexibilidade na escolha dos eletrólitos da CE. O uso de uma interface ortogonal à entrada da amostra (contra-eletrodo) no MS reduz o risco de contaminação ou obstrução da entrada do MS e permite o uso de tampões eletroforéticos moderadamente não voláteis, podendo melhorar a separação dos analitos.…”