Analysis of Five Earthy-Musty Odorants in Environmental Water by HS-SPME/GC-MS

Zhen Ding,Xiaodong Chen,Lihong Yin,Shifu Peng,Weiwen Xia,Hao Zheng

doi:10.1155/2014/697260

Abstract

The pressing issue of earthy and musty odor compounds in natural waters, which can affect the organoleptic properties of drinking water, makes it a public health concern. A simple and sensitive method for simultaneous analysis of five odorants in environmental water was developed by headspace solid-phase microextraction (HS-SPME) coupled to chromatography-mass spectrometry (GC-MS), including geosmin (GSM) and 2-methylisoborneol (2-MIB), as well as dimethyl trisulfide (DMTS), β-cyclocitral, and β-ionone. Based on the simple modification of original magnetic stirrer purchased from CORNING (USA), the five target compounds can be separated within 23 min, and the calibration curves show good linearity with a correlation coefficient above 0.999 (levels = 5). The limits of detection (LOD) are all below 1.3 ng L−1, and the relative standard deviation (%RSD) is between 4.4% and 9.9% (n = 7) and recoveries of the analytes from water samples are between 86.2% and 112.3%. In addition, the storage time experiment indicated that the concentrations did not change significantly for GSM and 2-MIB if they were stored in canonical environment. In conclusion, the method in this study could be applied for monitoring these five odorants in natural waters.

Highlights

Earthy and musty odors in drinking water are often associated with the metabolites which are produced in the degradation of cyanobacteria, actinomyces, fungi, and blue-green algae [1,2,3], including geosmin (GSM) and 2-methylisoborneol (2-MIB), commonly found in lakes and reservoirs [4, 5]
Attention now is drawn to the compounds dimethyl trisulfide (DMTS), β-cyclocitral, and β-ionone, which are associated with algal blooms caused by eutrophication progress [6,7,8,9], and they often simultaneously break out in environmental waters [4, 10]
The storage time experiment indicated that the concentrations did not change significantly for both GSM and 2-MIB if they were stored in canonical environment in ten days

Summary

Introduction

Earthy and musty odors in drinking water are often associated with the metabolites which are produced in the degradation of cyanobacteria, actinomyces, fungi, and blue-green algae [1,2,3], including geosmin (GSM) and 2-methylisoborneol (2-MIB), commonly found in lakes and reservoirs [4, 5]. The odor threshold concentration (OTC) is extremely low, 10 ng L−1 or less for GSM and 2-MIB [14], for instance, which can be detected by human nose. The low threshold of detection can result in consumer complaints about the terrible malodors in recreational waters, aquatic products, and tap water, especially during the outbreak period of algal blooms [8, 15, 16], even if some other quality indicators of water, such as turbidity, number of algal cells, and suspended matter, are acceptable.

Methods

Results

Conclusion