Agilent supports GC/MS with fast, accurate FTIR screening of phthalates in toys

Frank Higgins
Agilent Senior Applications Development Scientist,
Molecular Spectroscopy

Alan Rein
Agilent Business Development Manager,
Molecular Spectroscopy

Many common plastic consumer products contain high levels of toxic chemical additives known as phthalates. Phthalates are referred to as plasticizers, which are used to make plastics more flexible, durable, and softer. Typically, 15-30% phthalates are added to a base polymer such as polyvinyl chloride (PVC) and other widely used polymers. Since there are no chemical bonds between the plasticizer and the polymer, the plasticizers can easily leach out, contaminating the surrounding environment or being ingested by humans. Phthalates are hormone disruptors and phthalate exposure is also linked to obesity, insulin resistance, kidney and liver damage, ADHD, and possibly other neurological effects in children [1].

Figure 1. Importance of pre-screening: Toy examples above are phthalate-free, while the toys shown below contain phthalates above the specified concentrations.

Regulations in the U.S. permanently prohibit the sale of any “children’s toy or childcare article” containing concentrations of more than 0.1% of three specified phthalates. In addition, three other phthalates are temporarily prohibited in the same products. FTIR spectroscopy is recommended as an optional pre-screening procedure for determining gross phthalate contamination. The concentration limit is based on the individual plasticized parts of a children’s toy or childcare product. Figure 1 illustrates examples of similar toys that may or may not contain phthalates.

Simple, rapid phthalates screening using
Agilent 4500 FTIR methodology

To address these safety concerns, a screening method for phthalates is needed that is more rapid, simple, and supportive of the regulatory approved gas chromatograph/mass spectroscopy (GC/MS) method. By screening samples, only those identified as PVC polymers, or polymers that show traces of ortho-phthalates, are sent for GC/MS analysis. In this article we will examine the use of Agilent FTIR methodology in the pre-screening of children’s toys for phthalates.

The portable Agilent 4500a FTIR is the primary choice for phthalate screening and, more generally, for the identification of plastics that may contain phthalates. The spectrometer features a three reflection diamond ATR (attenuate total reflectance) sensor on which the plastic samples are placed for measurement. Objects for analysis do not require sample preparation and the infrared spectral measurement is made in approximately 1 minute. The 4500 FTIR uses the the intuitive Agilent MicroLab software, and the imbedded method for phthalate analysis employs multiple calibrations. The software’s advanced condition reporting capability enables automatic selection of the best calibration, so that the method can measure phthalates even in the presence of other legal types of plasticizers.

In our test, a series of phthalates in PVC were prepared gravimetrically by a commercial laboratory using certified reagents (Table 1). The phthalates in the standards were a mixture of the permanently banned phthalates dioctyl phthalate (DOP or DEHP), dibutyl phthalate (DBP), and benzyl butyl phthalate (BBP), mixed with an approved replacement plasticizer, diisononyl cyclohexane-1,2-dicarboxylate (DINCH).

PVC products are produced with sufficient plasticizer to make them soft and pliable, typically 20-35 wt% total plasticizer. To reproduce a typical vinyl toy composition in the evaluation standards, the total plasticizer concentration of 33-35 wt% was used. The FTIR method, using the Agilent 4500 Series Portable FTIR, was calibrated with DEHP in PVC along with various replacement plasticizers. Testing the method with other types of banned phthalate, such as DBP and BBP, proves its effectiveness to detect any type of ortho-phthalate at the low levels required for screening purposes.

* The 4.0% relative uncertainty is based on errors from the weighing of the raw materials at 95% confidence level, or k = 2.
Table 1. Phthalates used as standards for evaluation.

The results from the Agilent 4500 FTIR total phthalate method are shown in Table 2. The data demonstrate that the FTIR values match well against samples prepared gravimetrically and can measure to levels required for screening purposes.

Table 2. Comparison of total phthalates measured gravimetrically and by FTIR.

The Agilent 4500 portable FTIR equipped with the exclusive phthalate method is being adopted by a number of organizations and companies that require a means to quickly screen plastic toys and other objects in order to help ensure that banned phthalates are either not present, or present below regulated levels. The speed of the FTIR method enables more objects to be screened, as well as flag suspect objects for further analysis by GC/MS for regulatory compliance. Learn more about fast FTIR screening for phthalates in Agilent publications 5991-5709EN and 5991-3649EN.

Agilent offers a full suite of reliable solutions for quick, accurate contaminant detection

Agilent’s suite of advanced detection instruments for consumer products helps you quickly and easily validate methods and results to ensure global compliance. For example, the 7890B GC and 5977A GC/MS deliver excellent sensitivity and selectivity for phthalate analysis. Advanced LC and LC/MS systems, and gel permeation/size exclusion chromatography systems, columns and standards, enable cost-effective, robust, and reliable results for product quality. Reliable and easy-to-use Agilent ICP-MS and ICP-OES solutions also deliver excellent levels of sensitivity for impurity analysis, ensuring safety and product quality at all production stages.

Explore more Agilent phthalate analysis applications by LC (5991-2784EN), LC/MS (5990-9597EN), GPC (5990-8324EN), and GC (A01462). Then contact your Agilent Representative today to find the perfect solution for your application.

Reference

1. Visit https://www.cpsc.gov/phthalates for further details regarding phthalate regulations and measurement.

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Article Directory – February 2016