Microporous Membrane Solid Phase Extraction Tested for Detecting Carcinogens in Smoker Urine

Scientists from Universidade Federal do Paraná in Curitiba, Brazil tested a new extraction device for determining carcinogenic aromatic amines in smoker urine. Their findings were published in the Journal of Chromatography A (1).

Close up male hand holding a cigarette. | Image Credit: © Nopphon - stock.adobe.com

Tobacco consumption is known to have carcinogenic side effects, which is part of why it remains a worldwide health issue. In 2016, approximately 5.7 trillion cigarettes were consumed worldwide, with China corresponding to 49.1% of all cigarette consumption. Carcinogens are substances that can increase the risk of developing cancer (2). More than100 carcinogens have been identified. These carcinogens can trigger a chain reaction that turns normal cells into cancerous cells.

Tobacco smoke can generate approximately 60 carcinogenic compounds, including aromatic amines (AA). AA is of particular interest for recent biomonitoring, with the Food and Drug Administration (FDA) and International Agency for Research on Cancer recognizing 1-naphthylamine (1-NA) and 2-naphthylamine (2-NA), two AA generated in tobacco burning, as having carcinogenic potential.

Analysis on these substances has become of interest lately, with miniaturized solid phase extraction techniques, such as microporous membrane solid phase extraction (MMSPE), showing potential for extracting aromatic compounds. For this study, the scientists developed a bioanalytical method for the determination of 1-NA and 2-NA in human urine; as part of this, polypropylene microporous membranes were used as a sorptive phase for MMSPE.

Urine samples were hydrolyzed using hydrochloric acid (HCl) for 1 h at 80 °C, with pH being adjusted to 10. Afterwards, ultrasound-assisted MMSPE procedures were optimized by factorial designs. To each sample, 750 µL of methanol was added, and ultrasound-assisted MMSPE was conducted for 1 h with four devices containing seven 2 mm polypropylene membrane segments. After extraction, the segments were transferred to 400 µL of hexane, and desorption was conducted for 30 min. Extracts were submitted to a simple and fast microwave-assisted derivatization procedure, by the addition of 10 µL of PFPA and heating at 480 W for 3 min, followed by clean-up with phosphate buffer pH 8.0 and GC–MS/MS analysis. Adequate linearity was obtained for both analytes in a range from 25 to 500 µg L⁻¹, while the multiple reaction monitoring approach provided satisfactory selectivity and specificity.

According to the scientists, this method provides the advantage of reduction of time required for derivatization; this stems from the use of a microwave-assisted approach instead of heating in a thermostatic bath, while ultrasound-assisted MMSPE took an amount of time compared to other MMSPE-based methods previously reported in the literature for determination of aromatic compounds. The stability of urine samples and derivatized extracts were successfully ascertained in working and storage conditions broached by the developed method. Further, in applying the method to urine samples provided by first- and second-hand smokers, 1-NA was found to be present in first-hand smokers’ urine, while none of the analytes were found in second-hand smoker samples.

Alongside these findings, MMSPE was shown to be applicable with polypropylene microporous membranes as an extraction technique for biological fluids, since this is the first method using urine as a matrix, and such matrices are highly complex. The range of compounds for which MMSPE devices can prove efficient was also broadened with this study, as according to the scientists, “this is the first method for the determination of AAs with polypropylene microporous membranes” (1). Though there is more research to be done, MMSPE devices can be considered a viable and low-cost alternative to devices used in previously reported bioanalytical methods for the determination of AAs in urine aiming at its biomonitoring.

References

(1) Cestaro, B. I.; Nagata, N.; da Silva, B. J. G. Evaluation of polypropylene microporous membranes as extraction devices for determination of carcinogenic aromatic amines in smoker urine by GC–MS/MS. J. Chromatogr. A 2024, 1729, 465030. DOI: 10.1016/j.chroma.2024.465030

(2) Carcinogens. Cleveland Clinic 2024. https://my.clevelandclinic.org/health/articles/25081-carcinogens (accessed 2024-6-25)