My research focuses on developing and applying innovative analytical techniques to address critical and emerging challenges in environmental science, agriculture, food science, and public health. My work centers on Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS), infrared spectroscopy (IR), and X-ray fluorescence spectroscopy (XRF).
My contributions include novel methods that advance chemical, physical, and biological analyses in complex systems. These methods help close knowledge gaps in the occurrence, behavior, and biological fate of target substances, supporting safer and more sustainable environmental, agricultural, and food systems while protecting public health.
Analytes of interest: pesticides, mycotoxins, heavy metals, food additives, microplastics, nanomaterials, bacteria, food and packaging analysis, hazard analysis, etc.
1. USDA-NIFA, 02/2026-01/2029, PI, ~ $800,000
Title: PARTNERSHIP: Development of a Green-Chemistry and Cost-Effective Method for Quantifying Inorganic Arsenic in High-Risk Food Products for Infants and Children
2. NIH R01, 01/01/24-10/31/28, Role: PI, ~ $1,900,000
Title: Novel approach for determining the age of mosquitoes
3. USDA-NIFA, 01/01/21-12/31/24, Role: PI, $469,900
Title: Investigate the impact of adjuvants on pesticide persistence and develop an effective strategy to reduce pesticide residues on fresh Produce
4. USDA-NIFA, 11/01/15-10/31/19, Role: PI, $473,628
Title: In situ and real time monitoring and characterization of pesticide residues on and in fresh produce using SERS
5. USDA-NIFA, 02/01/15-01/31/18, Role: PI, $444,200
Title: Development of a label-free SERS mapping-based platform for multi-bacterial detection in food
6. USDA-NIFA, 2/01/15-01/31/18, Role: PI, $499,500
Title: Investigate the interactions between silver nanoparticles and leafy vegetables using surface enhanced Raman spectroscopic mapping
1. Carroll, M., Gao, Z., He, L.. Comparison of Linear and Nonlinear Regression Models for Dual ED-XRF Analysis of Trace Arsenic and Lead in Rice-Based Foods. Applied Spectroscopy. 2026;0(0). doi:10.1177/00037028261492376
2. Guo, X., & He, L. (2026). Acetone-assisted enhancement of Raman detection of polystyrene nanoplastics. Food Bioscience, 80, 109045.
3. Zhang, Y., Pathak, S., Curry, G., Vu, N., Gao, Z., & He, L. (2026). A smartphone-based optical detection for rapid and reliable quantification of bacterial contamination on stainless-steel surfaces. Applied and Environmental Microbiology, 92, e00073-26. https://doi.org/10.1128/aem.00073-26
4. Carroll, M., Gao, Z., & He, L. (2026). Rapid and Accurate ED-XRF Quantification of Trace Arsenic in Rice-Based Foods Employing ANNs to Resolve Lead Spectral Interference. Foods, 15(7), 1130.
5. Forbes, A., & He, L. (2026). Rapid detection of erythrosine (FD&C Red 3) in candy using a paper-based SERS substrate and a handheld Raman spectrometer. Journal of Food Protection, 89(4), 100729. https://doi.org/10.1016/j.jfp.2026.100729
6. Carroll, M., Gao, Z., & He, L. (2026). Development of a rapid, minimally destructive, and accurate method to quantify arsenic in rice and rice-based foods utilizing X-ray fluorescence spectroscopy and chemometrics. Food Analytical Methods, 19, 72. https://doi.org/10.1007/s12161-025-02979-5
7. Adainoo, B., Gao, Z., & He, L. (2026). Real-time prediction of shelf-life of soymilk using a surface-enhanced Raman spectroscopy (SERS) fiber and convolutional neural networks. Sustainable Food Technology, 4, 1541-1549. https://doi.org/10.1039/D5FB00423C
8. Pandiangan, F. I., & He, L. (2026). Microplastics in the food system: Should we worry? Annual Review of Food Science and Technology, 17, 541-567. https://doi.org/10.1146/annurev-food-052924-062314
9. Usman, M., Zhang, Y., Rahman, H. U. U., Sahar, A., Aadil, R. M., Abdi, G., & He, L. (2025). Discrimination of porcine and bovine gelatin using Raman microspectroscopy coupled with chemometrics. Applied Food Research, 101350.
10. Adainoo, B., Gao, Z. and He, L., 2025. Headspace Analysis of Whole Milk Quality Using a Surface-Enhanced Raman Spectroscopy-Active Fiber and Convolutional Neural Networks. ACS Food Science & Technology, 5(4), pp.1504-1512.
11. Du, X., Doherty, J., Lee, J., Clark, J. M., & He, L. (2025). Assessment of the effect of non-ionic surfactant alkylphenol ethoxylates on the penetration of pesticides in fresh produce. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 330, 125691.
12. Patel, J. D., Gao, Z., & He, L. (2025). FTIR spectroscopic analysis of plant proteins and correlation with functional properties. Journal of AOAC International, 108(3), 348–356.
13. Shao, Y., He, L., & Zheng, H. (2025). Prediction of phase stability of UHT reconstituted skim milk after ambient storage using Raman spectroscopy. International Dairy Journal, 161, 106142.
14. Usman, M., Mac Regenstein, J., Rahman, H. U. U., Ishaq, A., Khan, M. I., Sahar, A., Abdi, G., Aadil, R. M., & He, L. (2025). Structural and functional characterization of Coryphaena hippurus skin gelatin with commercial porcine gelatin. Applied Food Research, 5(1), 100898.
15. Gao, Z., Zhang, Y., Harrington, L. C., Murdock, C. C., Martin, E., Manbeck-Mosig, D., Vetrone, S., Tremblay, N., Barker, C. M., Clark, J. M., He, L., & Zhu, W. (2025). Determining mosquito age using surface-enhanced Raman spectroscopy and artificial neural networks: Insights into the influence of origin and sex. Parasites & Vectors, 18, 218. https://doi.org/10.1186/s13071-025-06831-x
16. Sankaranarayanan, P., Li, J., Gao, Z., & He, L. (2025). Rapid detection of titanium dioxide in powdered food products using X-ray fluorescence spectroscopy. Journal of Food Composition and Analysis, 108019.
17. Usman, M., Mac Regenstein, J., Rahman, H. U. U., Sahar, A., Aadil, R. M., Tariq, A., Fatima, I., Bilal, A., & He, L. (2025). Physicochemical and functional properties of rainbow trout (Oncorhynchus mykiss) skin gelatin in comparison to commercial bovine gelatin. Food Chemistry Advances, 101088.
18. Gao, W., Du, X., Gao, Z., Dai, H., Li, L., Zhang, B., Wang, G., Chen, X., Doherty, J., Clark, J. M., Hou, R., Luo, F., & He, L. (2025). Assessing the effect of a non-ionic surfactant on surface degradation of the pesticide acetamiprid on live tea plants. Food Research International, 221(2), 117341. https://doi.org/10.1016/j.foodres.2025.117341
19. Du, X., Ho, L., Li, S., Doherty, J., Lee, J., Clark, J. M., & He, L. (2025). Efficacy of household and commercial washing agents in removing the pesticide thiabendazole residues from fruits. Foods, 14(2), 318.
20. Du, X., Doherty, J., Lee, J., Clark, J. M., & He, L. (2025). Investigating the impact of crop oil concentrate on the persistence and penetration of pesticides applied on apples. ACS Agricultural Science & Technology. https://doi.org/10.1021/acsagscitech.4c00587
21. Zhang, Y., Gao, Z., & He, L. (2024). Integration of surface swab with optical microscopy for detection and quantification of bacterial cells from stainless-steel surfaces. Letters in Applied Microbiology, 77(10), ovae089.
22. Guo, X., Dai, H., & He, L. (2024). Migration testing of microplastics from selected water and food containers by Raman microscopy. Journal of Hazardous Materials, 462, 132798.
23. Du, X., Gao, Z., & He, L. (2024). Quantifying the effect of non‐ionic surfactant alkylphenol ethoxylates on the persistence of thiabendazole on fresh produce surface. Journal of the Science of Food and Agriculture, 104(5), 2630–2640.
24. Zhang, Y., Gao, Z., & He, L. (2024). Optical detection and enumeration of Escherichia coli and Salmonella enterica using a low-magnification light microscope. Journal of Microbiological Methods, 226, 107041.
25. Gao, W., Du, X., Gao, Z., Dai, H., Liu, D., Doherty, J., ... & He, L. (2024). Surface dissipation and foliar penetration of acetamiprid on tea leaves in the presence or absence of adjuvants. LWT, 205, 116536.
26. Gao, Z., Harrington, L. C., Zhu, W., Barrientos, L. M., Alfonso-Parra, C., Avila, F. W., Clark, J. M., & He, L. (2023). Accurate age-grading of field-aged mosquitoes reared under ambient conditions using surface-enhanced Raman spectroscopy and artificial neural networks. Journal of Medical Entomology, 60(5), 917–923.
27. Guo, X., Dai, H., Gukowsky, J., Tan, X., & He, L. (2023). Detection and quantification of microplastics in commercially bottled edible oil. Food Packaging and Shelf Life, 38, 101122.
28. Dai, H., Gao, Q., Lu, J., & He, L. (2023). Improving the accuracy of saffron adulteration classification and quantification through data fusion of thin-layer chromatography imaging and Raman spectral analysis. Foods, 12(12), 2322.
29. Dai, H., & He, L. (2023). Mirror-stamping: A new TLC-SERS method for color authentication. Talanta Open, 7, 100237.
30. Du, X., Gao, Z., Yang, T., Qu, Y., & He, L. (2023). Understanding the impact of a non-ionic surfactant alkylphenoxylate on surface-enhanced Raman spectroscopic analysis of pesticides on apple surfaces. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 301, 122954.
31. Wang, D., Du, X., & He, L. (2022). Investigation of the impact of a pesticide adjuvant on dimethoate persistence, penetration, and stability on apples using surface-enhanced Raman spectroscopy. ACS Agricultural Science & Technology. https://doi.org/10.1021/acsagscitech.2c00092
32. Gukowsky, J. C., & He, L. (2022). Development of a portable SERS method for testing the antibiotic sensitivity of foodborne bacteria. Journal of Microbiological Methods, 106496.
33. Guo, X., Lin, H., Xu, S., & He, L. (2022). Recent advances in spectroscopic techniques for the analysis of microplastics in food. Journal of Agricultural and Food Chemistry, 70(5), 1410–1422.
34. Wang, D., Yang, J., Pandya, J., Clark, J. M., Harrington, L. C., Murdock, C. C., & He, L. (2022). Quantitative age grading of mosquitoes using surface‐enhanced Raman spectroscopy. Analytical Science Advances, 3(1–2), 47–53.
35. Gukowsky, J. C., Yang, T., & He, L. (2022). Assessment of three SERS approaches for studying E. coli O157:H7 susceptibility to ampicillin. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 264, 120239.
36. Shen, Y., Borgatta, J., Ma, C., Singh, G., Tamez, C., Schultes, N. P., Zhang, Z., Dhankher, O. P., Elmer, W. H., He, L., & Hamers, R. J. (2022). Role of foliar biointerface properties and nanomaterial chemistry in controlling Cu transfer into wild-type and mutant Arabidopsis thaliana leaf tissue. Journal of Agricultural and Food Chemistry, 70(14), 4267–4278.