📄 chemistry

Fabric Phase Sorptive Extraction -Silica-based Sol–Gel Sorbent for Simultaneous Extraction of Pyrene, Chrysene, and Benzo[a]pyrene from Urine Samples

This study presents a rapid and sensitive Fabric Phase Sorptive Extraction (FPSE) method using a silica-based sol–gel sorbent coupled with HPLC-UV for the simultaneous determination of pyrene, chrysene, and benzo[a]pyrene in urine samples, offering a reliable, solvent-efficient alternative for assessing human exposure to polycyclic aromatic hydrocarbons.

Original authors: Reyhaneh Ghorbani pour, Seyed Jamaleddin Shahtaheri, Vida Shahbazian, Masood Hamadanian, Monireh Khadem

Published 2026-07-08

📖 5 min read🧠 Deep dive

CC BY 4.0

Original authors: Reyhaneh Ghorbani pour, Seyed Jamaleddin Shahtaheri, Vida Shahbazian, Masood Hamadanian, Monireh Khadem

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

The Big Picture: Catching Invisible Pollutants in a Cup of Pee

Imagine your body is a house, and Polycyclic Aromatic Hydrocarbons (PAHs)—dangerous chemicals found in car exhaust, cigarette smoke, and burnt food—are like tiny, invisible dust motes that have managed to sneak inside. Scientists want to know how much of this "dust" is in the house. The best way to check is to look at the "trash" the house throws out: urine.

However, finding these tiny chemical dust motes in a cup of urine is like trying to find a single grain of sand in a bucket of muddy water. The urine is too messy (complex), and the chemicals are too small and slippery to catch easily with old-fashioned tools.

This paper introduces a new, high-tech "net" called Fabric Phase Sorptive Extraction (FPSE) to catch these chemicals (specifically Pyrene, Chrysene, and Benzo[a]pyrene) so they can be counted accurately.

The New Tool: The "Magic Sponge" on a Fabric

The researchers didn't use a standard sponge or a filter. They created a special fabric patch coated with a "magic gel" (a silica sol–gel).

The Fabric: Think of this as a tiny piece of cloth (like a bandage).
The Gel Coating: This is the secret sauce. It's a chemical layer that acts like a magnet specifically designed to attract those three dangerous PAH chemicals. Because the gel is porous (full of tiny holes), the chemicals can swim right into it and get stuck.
The Advantage: Unlike old methods that clog up or need gallons of toxic chemicals to work, this fabric patch is tough, doesn't break down easily, and works in almost any liquid environment.

How the Process Works (Step-by-Step)

The Dip: You take a small piece of this special fabric and dip it into the urine sample.
The Catch: The fabric sits there for about an hour. The "magnet" on the fabric grabs the PAHs and holds them tight, leaving the rest of the urine behind.
The Wash: You take the fabric out and dip it into a tiny drop of a cleaning liquid (acetonitrile). This liquid is like a "release agent" that convinces the chemicals to let go of the fabric and jump into the liquid.
The Count: That tiny drop of liquid is then fed into a machine (HPLC) that acts like a super-sensitive scanner. It counts exactly how many chemical molecules were caught.

Tuning the Machine: Finding the Perfect Settings

The researchers spent a lot of time figuring out the "Goldilocks" settings to make this work perfectly. They tested many variables, much like a chef tasting a soup to get the seasoning right:

How much urine? They found that 10 mL (about two tablespoons) was the sweet spot. Too much urine, and the fabric gets overwhelmed; too little, and you don't catch enough.
How long to soak? 1 hour was perfect. Soaking longer didn't help; in fact, waiting too long (6 hours) actually made the chemicals slip back out of the fabric.
How fast to stir? They spun the sample at 1000 rpm (very fast). Think of this as shaking a salad dressing vigorously to make sure the oil and vinegar mix well; the fast spinning helps the chemicals find the fabric faster.
The Salt Factor: Adding 15% salt to the urine helped. It's like adding salt to water to make it harder for the chemicals to stay dissolved, forcing them to jump onto the fabric instead.
The Size: A 2x2 cm piece of fabric (about the size of a postage stamp) worked best. It had enough surface area to catch a lot of chemicals without needing a huge amount of cleaning liquid.
The pH: The urine needed to be neutral (pH 7). If it was too acidic or too soapy (basic), the chemicals wouldn't stick to the fabric.

The Results: A Clean, Fast, and Accurate Catch

The team proved that their new method works incredibly well:

It's Sensitive: It can find very tiny amounts of these chemicals (as low as 0.2 parts per million).
It's Reliable: If they tested the same sample five times in one day, or on five different days, they got almost the exact same result every time.
It's Clean: They used very little toxic solvent (only 1 mL of cleaning liquid), which is much better for the environment and the lab workers than older methods that use liters of chemicals.
It's Fast: The whole process, from dipping the fabric to getting the result, is much quicker than traditional methods.

The Bottom Line

This paper describes a new, smarter way to clean up a urine sample before testing it. By using a special "magnetic" fabric patch, scientists can now catch dangerous pollution chemicals more easily, faster, and with less waste than before. This makes it a powerful tool for checking if people are being exposed to harmful pollutants in their daily lives or workplaces.

Note: The paper focuses strictly on the development and testing of this extraction method in a lab setting. It does not claim to diagnose diseases or treat patients, but rather provides a better tool for measuring exposure.

Technical Summary: Fabric Phase Sorptive Extraction with Silica-based Sol–Gel Sorbent for PAHs in Urine

Problem Statement
Polycyclic aromatic hydrocarbons (PAHs), specifically pyrene, chrysene, and benzo[a]pyrene, are recognized for their carcinogenic and mutagenic properties. While air sampling is common, it fails to account for dermal and ingestion exposure routes, necessitating biological monitoring via matrices such as urine. However, the complexity of biological samples makes the preparation of urine for PAH analysis time-consuming and challenging. Conventional techniques like solid-phase extraction (SPE), liquid–liquid extraction (LLE), and solid-phase microextraction (SPME) often suffer from limitations including column clogging, high organic solvent consumption, and low extraction efficiency. There is a need for advanced, cost-effective sample preparation methods that ensure high accuracy and precision while minimizing pre-treatment steps.

Methodology
This study employed Fabric Phase Sorptive Extraction (FPSE) coupled with High-Performance Liquid Chromatography (HPLC) and UV detection to extract and quantify pyrene, chrysene, and benzo[a]pyrene from urine samples.

Sorbent Development: A sol–gel coated sorbent was synthesized using a phenyl/methyl/poly(dimethylsiloxane) (PDMS) composition. The phenyl groups were selected to facilitate $\pi$ – $\pi$ interactions with the target PAHs. The sol–gel solution was prepared with specific molar ratios of PDMS polymer, methyltrimethoxysilane, phenyltrimethoxysilane, and other reagents, followed by ultrasonication.
Fabric Preparation: Polyester fabric was activated via sequential NaOH and HCl washes, dried, and then coated with the sol–gel solution via immersion. The coated membranes underwent thermal conditioning and cleaning to ensure stability and remove unbonded residues.
Extraction Protocol: The optimized FPSE procedure involved immersing a 2×2 cm sol–gel coated membrane into 10 mL of urine samples (diluted 10-fold, pH 7) for 1 hour at a stirring rate of 1000 rpm. Ionic strength was adjusted to 15% using sodium chloride.
Desorption and Analysis: Following extraction, analytes were desorbed using 1 mL of acetonitrile via centrifugation. The desorbed samples were analyzed using a C18 column with a gradient mobile phase of acetonitrile and water. Detection wavelengths were optimized for each analyte (270 nm for pyrene, 290 nm for benzo[a]pyrene, and 390 nm for chrysene).

Key Contributions and Optimization
The study systematically optimized critical variables to maximize extraction recovery:

Sample Volume: 10 mL was identified as optimal; larger volumes (15–20 mL) reduced efficiency due to sorbent capacity limits.
Sorbent Size: A 2×2 cm membrane provided the highest surface area and extraction efficiency compared to smaller sizes.
Extraction Time: Equilibrium was reached within 1 hour; longer immersion times (4–6 hours) led to decreased recovery, likely due to back-diffusion or saturation.
Desorption Conditions: Acetonitrile was superior to methanol and dichloromethane for desorption, offering a balance of solubility and HPLC compatibility. A volume of 1 mL and a desorption time of 10 minutes yielded the best results.
Matrix Conditions: A neutral pH (7) and 15% ionic strength were determined to be optimal for maximizing analyte transfer to the sorbent.

Results
The developed method demonstrated high linearity, sensitivity, and precision:

Linearity: Calibration curves in both water and urine matrices showed correlation coefficients ( $r^2$ ) ranging from 0.9836 to 0.995.
Sensitivity: The method achieved low limits of detection (LOD) and quantification (LOQ). Specifically, LODs were 0.9 ppm for pyrene and 0.6 ppm for chrysene and benzo[a]pyrene. LOQs were 0.3 ppm for pyrene and 0.2 ppm for the other two analytes.
Precision and Accuracy: Intra-day relative standard deviations (RSD) ranged from 2.25% to 4.05%, and inter-day RSDs ranged from 3.93% to 5.27%. Extraction recoveries (RR) were between 93.4% and 96.6%, well within acceptable validation limits.
Separation: The HPLC system successfully resolved the three PAHs with distinct, non-overlapping peaks and a total run time of less than 10 minutes.

Significance and Claims
The authors claim that this FPSE-HPLC approach offers a reliable, simplified alternative to conventional sample preparation techniques. By utilizing a sol–gel coated silica-based sorbent, the method eliminates the need for complex urine pre-treatment steps, thereby reducing analysis time and the consumption of organic solvents. The sol–gel coating provides high thermal and chemical stability, allowing direct contact with the sample matrix. The study concludes that the method is a robust tool for the simultaneous extraction and determination of PAHs in biological samples, suitable for applications in environmental, occupational health, and toxicological studies. The authors note that while FPSE is not yet commercially ubiquitous, its high accuracy, precision, and reproducibility have established it as a practical laboratory technique.