Outline

  • Abstract
  • Keywords
  • Introduction
  • Reagents
  • Instrumentation
  • Shs Extraction Procedure
  • Gas Chromatography-Mass Spectrometry Analysis
  • Sampling
  • Results and Discussion
  • Screening Design
  • Optimization Design
  • Real Samples Analysis
  • Conclusion
  • References

رئوس مطالب

  • چکیده
  • کلیدواژه ها
  • مقدمه
  • واکنش گر ها
  • ابزار
  • روش استخراج SHS
  • تجزیه و تحلیل طیف سنجی جرمی کروماتوگرافی گاز
  • نمونه برداری
  • نتایج و مباحث
  • طراحی غربالگری
  • طراحی بهینه سازی
  • تجزیه و تحلیل نمونه های واقعی
  • نتیجه

Abstract

Static headspace coupled with gas chromatography-mass spectrometry was applied to extraction and analysis of volatile organic compounds in water samples. The effects of various factors affecting on the extraction efficiency including: the extraction temperature, extraction time, salt concentration and stirring speed were carried out by means of a 24 full factorial design. It was found that the effects of extraction temperature and salt concentration were signi?cant. Then, a central composite design was performed to optimize the level of these factors. The optimal headspace conditions were achieved when the vials were heated under 88°C and 29% w/w addition of salt. At optimum operating conditions, analytical figures of merit of method such as linearity (0.9962-0.9996), repeatability (1.2-12.13%), detection limits (0.1-4.9 μg.L−1) and linearity dynamic range (10-1000 μg.L−1) were determined. The proposed methods can be used to direct investigation of the presence of Volatile organic compounds in environmental samples without pretreatment of samples. Finally the optimized method was used to investigate the existence of volatile organic compounds in Babolroud River in the north of Iran.

Keywords: - - -

Conclusions

In this work, the effect of different factors on the SHS extraction efficiency of VOCs was studied by performing a 24 full factorial experimental design. The results showed that the percent of NaCl in the water samples and the extraction temperature were dominant factors in extraction efficiency of SHS. The results of VOCs analysis in optimum conditions indicated that the analytical figures of merits of the proposed method are comparable with other methods.

The main advantage of proposed protocol is that greatly decreased the risk of contamination or sample loss that can occur in other processes. No potential interferences are introduced, minimizing the problems associated with the sample matrix. The sampling is fast and does not require expensive materials or extensive laboratory work. In addition, it does not use solvents, concentrating samples instead of diluting them, as it often happens when solvent extraction is used.

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