1. Markus, V., Paul, A. A., Marks, R. S., & Caleb, J. (2026). Smartphone digital image colorimetry: An affordable easy-to-use technique. Analytical Letters, 59(1), 158–176.
  2. Ismail, S., Caleb, J., Abdullahi, A. B., Abughrin, S. E., & Al-Nidawi, M. (2025). Edible oil-based switchable-hydrophilicity solvent liquid-liquid microextraction coupled with HPLC-DAD for determination of parabens in food and pharmaceutical products. Journal of Food Composition and Analysis, 137, 106857.
  3. Al-Nidawi, M., & Caleb, J. (2025). Evaluation of the greenness of a supramolecular solvent liquid-liquid microextraction prior to HPLC for the determination of Sudan dyes in spices. Analytical Letters, 58, 1–17.
  4. Markus, V., Venn, C., Ismail, S., & Caleb, J. (2025). Deep eutectic solvent liquid-liquid microextraction prior to smartphone digital image colorimetry for the determination of iodate in table salt. Analytical Letters, 58(11), 1893–1905.
  5. Ahmad, B. I., Ismail, S., Caleb, J., Asir, S., & Usman, A. G. (2025). Smartphone digital image colorimetry coupled with chemometric approach for determination of boron in nuts prior to deep eutectic solvent liquid-liquid microextraction. Analytical Sciences, 41(4), 403–418.
  6. Al-Nidawi, M., Uzcan, F., Alshana, U., & Soylak, M. (2024). Switchable-hydrophilicity solvent liquid-liquid microextraction prior to spectrophotometric determination of Sudan I dye in spices. Analytical Letters, 57(2), 202–212.
  7. Al-Nidawi, M., Ozalp, O., Alshana, U., & Soylak, M. (2024). Cloud point microextraction prior to flame-atomic absorption spectrometry for the determination of zinc ethylene-1,2-bisdithiocarbamate in food and environmental samples. Analytical Letters, 57(8), 1313–1324.
  8. Ismail, S., Abdullahi, A. B., & Alshana, U. (2024). Edible oil-based switchable-hydrophilicity solvent liquid-liquid microextraction prior to smartphone digital image colorimetry for the determination of total curcuminoids in food samples. Analytical Methods, 16(24), 3983–3992.
  9. Al-Nidawi, M., Ozalp, O., Alshana, U., & Soylak, M. (2023). Synergistic cloud point microextraction prior to spectrophotometric determination of curcumin in food samples. Analytical Letters, 56(12), 1977–1988.
  10. Abdullahi, A. B., Ismail, S., Alshana, U., & Ertas, N. (2023). Smartphone digital image colorimetry combined with deep eutectic solvent liquid-liquid microextraction for the determination of cobalt in milk and dairy products. Journal of Food Composition and Analysis, 119, 105263.
  11. Abdullahi, A. B., Ismail, S., & Alshana, U. (2023). Edible oil-based switchable-hydrophilicity solvent liquid-liquid microextraction for the determination of lead in food samples using flame-atomic absorption spectrometry. Journal of Food Composition and Analysis, 118, 105189.
  12. Ismail, S., Abdullahi, A. B., Alshana, U., & Ertas, N. (2023). Switchable-hydrophilicity solvent liquid-liquid microextraction combined with smartphone digital image colorimetry for the determination of palladium in catalytic converters. Analytical Sciences, 39(1), 97–108.
  13. Caleb, J., Alshana, U., & Ertas, N. (2021). Smartphone digital image colorimetry combined with solidification of floating organic drop-dispersive liquid-liquid microextraction for the determination of iodate in table salt. Food Chemistry, 336, 127708.
  14. Caleb, J., & Alshana, U. (2021). Supramolecular solvent liquid-liquid microextraction followed by smartphone digital image colorimetry for the determination of curcumin in food samples. Sustainable Chemistry and Pharmacy, 21, 100424.
  15. Al-Nidawi, M., & Alshana, U. (2021). Reversed-phase switchable-hydrophilicity solvent liquid-liquid microextraction of copper prior to its determination by smartphone digital image colorimetry. Journal of Food Composition and Analysis, 104, 104140.
  16. Abughrin, S., Alshana, U., & Caleb, J. (2022). Smartphone digital image colorimetry for the determination of aluminum in antiperspirant products. Turkish Journal of Pharmaceutical Sciences, 19(6), 618.
  17. Agiel, N., Caleb, J., Mericli, A. H., Alshana, U., & Mericli, F. (2022). Comparison and validation of bioactive flavonoids by reverse phase high performance liquid chromatography in Crataegus species related to pharmaceutical Crataegus products. Indian Journal of Pharmaceutical Sciences, 84(2), 444–452.
  18. Caleb, J., Alshana, U., Hanoglu, A., & Calis, I. (2021). Dispersive liquid-liquid microextraction for the isolation and HPLC-DAD determination of three major capsaicinoids in Capsicum annuum L. Turkish Journal of Chemistry, 45(2), 420–429.
  19. Markus, V., Dalmizrak, O., Edebal, O. H., Al-Nidawi, M., & Caleb, J. (2023). Smartphone digital image colorimetry for quantification of serum proteins. Analytical Methods, 15(38), 5018–5026.
  20. Ismail, S., Abdullahi, A. B., Alshana, U., & Ertas, N. (2023). Switchable-hydrophilicity solvent liquid-liquid microextraction combined with smartphone digital image colorimetry for the determination of palladium in catalytic converters. Analytical Sciences, 39(1), 97–108.
  21. Alshana, U., Hassan, M., Al-Nidawi, M., Yilmaz, E., & Soylak, M. (2020). Switchable-hydrophilicity solvent liquid-liquid microextraction. TrAC Trends in Analytical Chemistry, 131, 116025.
  22. Al-Nidawi, M., Alshana, U., Caleb, J., Hassan, M., Rahman, Z. U., Yigit Hanoglu, D., & Calis, I. (2020). Switchable-hydrophilicity solvent liquid-liquid microextraction versus dispersive liquid-liquid microextraction prior to HPLC-UV for the determination and isolation of piperine from Piper nigrum L. Journal of Separation Science, 43(15), 3053–3060.