Validasi Metode Penetapan Kadar Vitamin C pada Kentang Secara Spektrofotometri UV

Abstract

Vitamin C dalam kentang dapat ditentukan secara spektrofotometri UV karena menyerap cahaya ultraviolet dengan kuat pada panjang gelombang 242 nm. Penelitian ini bertujuan memvalidasi metode spektrofotometri UV untuk penentuan kadar vitamin C pada kentang serta membandingkan hasilnya dengan metode iodimetri. Validasi metode yang diuji antara lain, linearitas, batas deteksi (LOD), batas kuantifikasi (LOQ), spesifisitas, presisi, akurasi, dan stabilitas. Hasil penelitian menunjukkan linearitas yang sangat baik dengan koefisien korelasi (r) sebesar 0,9999, LOD 0,03 mg/L, LOQ 0,11 mg/L, interferensi 0,30%, presisi dengan %RSD 0,13–0,36%, serta akurasi dengan % perolehan kembali 95,93–101,69%. Kadar vitamin C kentang yang diperoleh dengan spektrofotometri UV sebesar 9,97 mg/100 g, lebih rendah dibandingkan iodimetri sebesar 12,94 mg/100 g. Hasil ini menunjukkan bahwa metode spektrofotometri UV memiliki linearitas, akurasi, dan presisi yang baik dan dapat digunakan untuk penetapan kadar vitamin C pada kentang.

Vitamin C is a water-soluble vitamin that is highly susceptible to oxidation, requiring an accurate analytical method for its determination. This study aimed to validate a UV spectrophotometric method for determining vitamin C content in potatoes and compare the results with iodimetry. Analysis was performed at a wavelength of 242 nm, and method validation was conducted according to ICH guidelines, including linearity, limit of detection (LOD), limit of quantification (LOQ), specificity, precision, accuracy, and stability. The results showed excellent linearity with a correlation coefficient (r) of 0.9999, LOD of 0.03 mg/L, LOQ of 0.11 mg/L, interference of 0.30%, precision (%RSD) of 0.13–0.36%, and recovery values of 95.93–101.69%. Vitamin C standard solutions were more stable under refrigerated conditions than at room temperature. The vitamin C content of potatoes determined by UV spectrophotometry was 9.97 mg/100 g, lower than that obtained by iodimetry (12.94 mg/100 g). These findings indicate that the validated UV spectrophotometric method is suitable for determining vitamin C in potatoes.