Page 65 - Pharmaceutical Solution for Pharma Analysis

Analysis of styrene leached from polystyrene cups
using GCMS coupled with Headspace (HS) sampler

Introduction

Worldwide studies have revealed the negative impacts of body and can therefore disrupt normal hormonal
household disposable polystyrene cups (Figure 1) on functions. This could also lead to breast and prostate
human health and environment. cancer.
Molecular structure of styrene is shown in Figure 2. Styrene The objective of this study is to develop a sensitive,
is considered as a possible human carcinogen by the WHO selective, accurate and reliable method for styrene
[1]
and International Agency for Research on Cancer (IARC). determination using low carryover headspace sampler,
Migration of styrene from polystyrene cups containing HS-20 coupled with Ultra Fast Scan Speed 20,000 u/sec,
[2]
beverages has been observed. Styrene enters into our GCMS-QP2010 Ultra to assess the risk involved in using
body through the food we take, mimics estrogens in the polystyrene cups.

Figure 1. Polystyrene cup Figure 2. Structure of styrene

Method of Analysis

Extraction of styrene from polystyrene cups
This study was carried out by extracting styrene from commercially available polystyrene cups and recoveries were
established by spiking polystyrene cups with standard solution of styrene. Solutions were prepared as follows,

1) Standard Stock Solution:
1000 ppm of styrene standard stock solution in DMF: Water-50:50 (v/v) was prepared. It was further diluted with
water to make 100 ppm and 1 ppm of standard styrene solutions.
2) Calibration Curve:
Calibration curve was plotted using standard styrene solutions in the concentration range of 1 to 50 ppb with water as
a diluent. 5 mL of each standard styrene solution was transferred in separate 20 mL headspace vials and crimped with
automated crimper.
3) Sample Preparation:
150 mL of boiling water (around 100 ºC) was poured into polystyrene cups. The cup was covered with aluminium foil
[1]
and kept at room temperature for 1 hour. After an hour, 5 mL of sample from the cup was transferred into the 20 mL
headspace vial and crimped with automated crimper.

Method was partly validated to support the findings by performing reproducibility, linearity, LOD, LOQ and recovery
studies. For validation, solutions of different concentrations were prepared using standard stock solution of styrene (1000
ppm) as mentioned in Table 1.

2