, Volume 405, Issue 15, pp 5333-5339
Date: 04 Apr 2013

Determining urea levels in dialysis human serum by means of headspace solid phase microextraction coupled with ion mobility spectrometry and on the basis of nanostructured polypyrrole film

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Abstract

A simple and sensitive headspace (HS) solid phase microextraction (SPME) coupled with ion mobility spectrometry (IMS) method is presented for analysis of urea in dialysis human serum samples. A dodecylbenzenesulfonate-doped polypyrrole coating was used as a fiber for SPME. The HS-SPME–IMS method exhibits good repeatability (relative standard deviation of 3 % or less), simplicity, and good sensitivity. The influence of various analytical parameters such as pH, ionic strength, extraction time and temperature was investigated and the parameters were optimized. The calibration graph was linear in the range from 5 to 50 μg mL−1, and the detection limit was 2 μg mL−1. The method was applied successfully for determination of urea in human serum and with acceptable recovery (more than 98 %). Finally, a standard addition calibration method was applied to the HS-SPME-IMS method for the analysis of human serum samples before and at the end of dialysis. The proposed method appears to be suitable for the analysis of urea in serum samples as it is not time-consuming and requires only small quantities of the sample without any derivatization process.

Figure

The ion mobility spectrum obtained by HS-SPME–IMS using a PPy fiber under optimum conditions from headspace of 5 mL (A): 2 µg mL-1 of urea solution, (B): non-spiked control serum sample, (C): non-spiked patient 1 serum sample before dialysis, (D) non-spiked patient 1 serum sample at the end of dialysis, (E) spiked patient 1 serum sample at the end of dialysis with 10 µg mL−1 of urea, (F): non-spiked patient 2 serum sample before dialysis, (G): non-spiked patient 2 serum sample at the end of dialysis, (H): spiked patient 2 serum sample at the end of dialysis with 10 µg mL−1 of urea