Rapid, Sensitive, and Robust Detection of Phthalates in Food Using GC/MS or LC/MS

Significance of the topic

Phthalates are widely used plasticizers that can migrate into food and beverages, leading to human exposure and potential health risks such as endocrine disruption and reproductive abnormalities.
Recent food safety incidents involving illegal phthalate adulteration underline the need for rapid, sensitive, and reliable analytical methods to monitor regulatory limits.

Objectives and study overview

This work presents the development and validation of quantitative methods for the detection of phthalates in food matrices using both gas chromatography–mass spectrometry (GC/MS and GC/MS/MS) and liquid chromatography–mass spectrometry (LC/MS and LC/MS/MS).
The focus is on six regulated phthalates in the EU and USA, as well as broader screening of up to 30 phthalate compounds.

Methodology and instrumentation

Sample preparation:

• GC: Solid-phase extraction with Agilent Chem Elut cartridges to replace traditional hexane liquid-liquid extraction, reducing background and speeding processing (<10 min).
• LC: Methanol extraction with sonication (20 min) for beverages, powders, healthcare products, with internal standard addition before cleanup.

Chromatographic and MS Conditions:

• GC/MS: Agilent 7890A GC with J&W DB-5MS Ultra Inert column (30 m × 0.25 mm, 0.25 µm), splitless injection, temperature ramp from 120 °C to 300 °C; detection on 5975C MSD (SIM/Scan) or 7000B triple quadrupole in MRM mode.
• LC/MS: Agilent 1260 RRLC on ZORBAX Eclipse Plus C18 (2.1 × 50 mm, 1.8 µm) or Eclipse Plus C18 (2.1 × 100 mm, 1.8 µm) at 25–50 °C; mobile phases water/methanol gradients; analysis on 6150 single quadrupole or 6400 triple quadrupole with ESI in positive mode.

Instrumentation summary:

• GC: Agilent 7890A with 5975C single quad MSD or 7000B triple quad GC/MS.
• LC: Agilent 1260 RRLC with 6150 single quad LC/MS or 6400 triple quad LC/MS/MS.

Main results and discussion

Sample preparation performance:

• Chem Elut SPE yielded virtually blank backgrounds compared to heavy carryover from hexane LLE, improving detection reliability.

Sensitivity and linearity:

• GC/MS (single quad) achieved detection down to 50 ppb for regulated phthalates with R² ≥ 0.992; triple quad GC/MS/MS showed similar sensitivity with R² ≥ 0.997.
• LC/MS/MS delivered instrument detection limits of 0.3–5 ppb for 13 phthalates with correlation coefficients ≥ 0.9947.

Reproducibility and selectivity:

• Six regulated phthalates demonstrated highly reproducible total ion current traces across six injections at 50 ppb.
• Simultaneous SIM and scan acquisition reduced false-positive identifications in GC/MS.

Real sample analysis:

• Retail beverage samples contained DINP and DEHP levels exceeding the 1 ppm regulatory limit in China and Taiwan; one sample showed DINP >100× the allowable level.
• Sports drink analysis by LC/MS/MS quantified DEHP at 1.05 ppm, slightly above the Taiwan FDA limit.

Benefits and practical applications

The described methods are platform-agnostic and adaptable to single or triple quadrupole instruments, enabling rapid screening and accurate quantification of regulated and emerging phthalates in diverse food matrices.
Reduced sample preparation steps and low detection limits ensure compliance with stringent safety standards.

Future trends and possibilities

Future developments may include high-throughput automation of sample extraction, integration with high-resolution MS for non-targeted screening of new plasticizers, and expansion of validated methods to complex matrices such as dairy and fatty foods.
Advanced data analysis algorithms could enhance identification confidence and regulatory compliance workflows.

Conclusion

Agilent’s GC/MS and LC/MS solutions provide robust, sensitive, and reproducible methods for rapid detection of phthalates in food and beverages, supporting laboratories in meeting global regulatory requirements and responding swiftly to food safety incidents.