Determination of Short Chain Chlorinated Paraffins in Textile Samples by GC-MS

Zeng Zheng

doi:10.11648/j.ajac.20190703.14

Abstract

The method of determining short-chain chlorinated paraffins in textiles by GC-MS was established. Short-chain chlorinated paraffins, short for SCCPs, are a mixture of polychlorinated n-alkanes. These high production volume chemicals are widely used as leather coating, plasticizers for PVC and chlorinated rubber and flame retardants for plastics and textile. Due to their toxicity, as well as capacity for bioaccumulation and persistence in the environmental residue, SCCPs have become an obviously environmental issue. The current analytical equipment combination are very expensive and require a lot of laboratory space and advanced skills for operation, a ready-to-use commercially available method with relatively short time and satisfactory sensitivity urge to be established. In this new method, samples were extracted by n-hexane under ultrasonic followed by concentration and constant-volume and then identified by GC-MS and quantified by external standard method. With this method, a good linear relationship was found between 5 μg/mL ~30μg/mL with a linear correlation coefficient (R<sup>2</sup>) above 0.995. The detection limit for SCCPs by this method was found to be as low as 10mg/kg. The recoveries of SCCPs in textiles at three levels which covers low, media and high concentration ranges are ranged from 82.3% to 106.9% with relative standard deviation (RSD) of 3.41%~7.61%(RSD, N = 6).

Highlights

[2] The classification of chlorinated paraffins (CPs) in general is based on chain length and is divided into three general groups: (1) short-chain CPs (SCCPs), which chain length range from C10 to C13; (2) medium-chain CPs (MCCPs) ), which chain length range from C14 to C17; (3) long-chain CPs (LCCPs), which chain length are above C17. [3]
The experimental results indicated that the detection limits of SCCPs (51.5%Cl), SCCPs (55.5%Cl), SCCPs (63%Cl) standard samples by this method were 9.64mg/kg, 9.73 mg/kg and 9.69 mg/kg respectively
[15] this method detection limits met the requirements for the detection of SCCPs in ecological textiles

Summary

Introduction

The chemical compounds defined as chlorinated paraffins (CPs), knowns as polychlorinated alkanes (PCA), are a complex mixture of different chlorinated hydrocarbons with variable composition, first introduced to the market in the 1930s. [1] This group contains many congeners with different carbon chain length from C10 to C30, diverse chlorination degree from 40% to 70% by weight, as well as structural and spatial isomers. [2] The classification of CPs in general is based on chain length and is divided into three general groups: (1) short-chain CPs (SCCPs), which chain length range from C10 to C13; (2) medium-chain CPs (MCCPs) ), which chain length range from C14 to C17; (3) long-chain CPs (LCCPs), which chain length are above C17. [3]Industrial synthesis of SCCPs are conducted by ways of chlorination of petroleum-based n-alkanes/paraffins, olefin and alkyne fractions. [4] Because of their chemical and thermal stabilities, SCCPs are often used as flame retardants, plasticizers, and additives in paints, sealants and metal working fluids. [4] SCCPs have been listed as candidate persistent organic pollutants (POPs) in the Stockholm Convention due to their persistence, bioaccumulation and toxicity. [5] The use of SCCPs in metal- and leather product has been restricted in the European Union since 2004 because of high toxicities. [6] In recent years, several international and national law regulations on the manufacturing process and application of SCCPs have been introduced. [7] Oeko-Tex Standard 100 has imposed restrictions in SCCPs within 0.1% since 2011and highlighted their mass concentration to 100mg/kg in 2008. [8] DeTox organization require its concentration in ecological textile within the limitation of 50mg/kg. [9]Recently, the most reliable approach are single column gasZeng Zheng et al.: Determination of Short Chain Chlorinated Paraffins in Textile Samples by GC-MS chromatography coupled with appropriate detectors including gas chromatography and mass spectrometer (GC-MS) [/10], gas chromatography-electron capture negative chemical ion source low/high resolution mass spectrometry (GC-ECNI-LRMS/HRMS) and gas chromatography-electron impact ionization mass spectrometry (GC-EI-MS) 11] and final determination with gas chromatography-flame ionization detector (GC-FID). [12] According to the Determination of Short-chain Chlorinated Paraffins in Textiles for Import and Export, ultrasonic extraction with n-hexane prior to the identification with gas chromatography-negative chemical ionization-mass spectrometry (GC-NICI-MS) and the quantification with gas chromatography-flame ionization detector (GC-FID). [13] This determination only processes in basis of the application of time-consuming and finance-consuming extraction techniques and purification solution. The chemical compounds defined as chlorinated paraffins (CPs), knowns as polychlorinated alkanes (PCA), are a complex mixture of different chlorinated hydrocarbons with variable composition, first introduced to the market in the 1930s. Zeng Zheng et al.: Determination of Short Chain Chlorinated Paraffins in Textile Samples by GC-MS chromatography coupled with appropriate detectors including gas chromatography and mass spectrometer (GC-MS) [/10], gas chromatography-electron capture negative chemical ion source low/high resolution mass spectrometry (GC-ECNI-LRMS/HRMS) and gas chromatography-electron impact ionization mass spectrometry (GC-EI-MS) 11] and final determination with gas chromatography-flame ionization detector (GC-FID). [12] According to the Determination of Short-chain Chlorinated Paraffins in Textiles for Import and Export, ultrasonic extraction with n-hexane prior to the identification with gas chromatography-negative chemical ionization-mass spectrometry (GC-NICI-MS) and the quantification with gas chromatography-flame ionization detector (GC-FID). There is still a lack of a clearly defined, optimized and validated analytical methods which might be implemented in everyday analytical laboratory practice in studies of SCCPs’ occurrence. [14]

Methods

Results

Conclusion