Simple Determination of Cystine in Artificial Urine and Drug Matrices Using Digital Image Colorimetry


Kustanto T. B., ZAMAN B. T., POLAT KORKUNÇ Ü., Gel M. S., BAKIRDERE S.

Analytical Letters, cilt.59, sa.5, ss.920-934, 2026 (SCI-Expanded, Scopus)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 59 Sayı: 5
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1080/00032719.2025.2517118
  • Dergi Adı: Analytical Letters
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, Chemical Abstracts Core, Chimica, Academic Search Ultimate (EBSCO), Biomedical Reference Collection: Corporate Edition (EBSCO)
  • Sayfa Sayıları: ss.920-934
  • Anahtar Kelimeler: Cystine, determination, digital image colorimetry, smartphone, spectrophotometry, urine
  • Sağlık Bilimleri Üniversitesi Adresli: Evet

Özet

Smartphone-based digital image colorimetry was developed for the determination of cystine in pharmaceutical formulations and artificial urine samples. A lab-made colorimetric box was designed for capturing the digital images of sample solutions using a smartphone. The developed method employs a simple colorimetric method called nitroprusside test which specifically targets free -SH groups. Cystine was reduced to cysteine before the colorimetric test was applied. The color intensity is inversely related to the concentration of the analyte. The best linearity was obtained with the G color channel. Digital image processing was performed using the RGB Color Detector mobile application to obtain analytical data. The developed method exhibited good linearity in the range of 29.7–00.3 mg/kg. The limits of detection and quantification were 9.7 mg/kg and 32.3 mg/kg, respectively. The percent recoveries were 104.2 ± 7.8% and 108.7 ± 4.6%, which proved the accuracy and applicability of the developed method.