Validasi Metode Penentuan Kadar Fe(II) Air Limbah Tambang Secara Spektrofotometri Serapan Atom

Abstract

Air banyak dimanfaatkan pada sektor pertambangan, menghasilkan limbah air tambang mengandung zat besi dengan konsentrasi berbahaya bagi linkungan. Penentuan kadar Fe(II) pada air limbah tambang di PT Bukit Asam menggunakan metode destruksi basah berbasis HNO3 65%, yaitu sebanyak 5 mL untuk setiap pengujian dengan potensi pencemaran lingkungan. Penelitian ini bertujuan memvalidasi metode modifikasi volume penggunaan HNO3 dari 5 mL menjadi 1 mL berdasarkan standar AOAC 2019. Parameter validasi meliputi linearitas, presisi, akurasi, Limit of Detection, Limit of Quantification, Robustness, dan Ruggedness. Hasil optimasi menunjukkan volume optimum HNO3 sebesar 1 mL. Validasi metode menunjukkan linearitas yang sangat baik (r2 = 0,9997), presisi (%RSD (5,01) = 15%), akurat (80% = %recovery (106,72) = 110%), Limit of Detection (0,1149 mg/L), robust (f hitung = f tabel), dan rugged (t hitung = t tabel), tetapi Limit of Quantification (0,3482 mg/L) melebihi konsentrasi analit (0,2125 mg/L). Oleh karena itu, metode dinyatakan tidak valid dan belum dapat diterapkan sebagai prosedur standar analisis zat besi dalam air limbah tambang.

Water was widely used in the mining sector, producing mine wastewater containing iron with concentrations that are dangerous for the environment. Determination of Fe(II) in mining wastewater at PT Bukit Asam used a wet destruction method based on 65% HNO3, namely 5 mL for each test which has the potential for environmental pollution. This study aimed to validate the method of modifying the volume of HNO3 used from 5 mL to 1 mL based on the 2019 AOAC standard. Validation parameters include linearity, precision, accuracy, Limit of Detection, Limit of Quantification, Robustness, and Ruggedness. The optimization results showed that the optimum volume of HNO3 was 1 mL. Method validation showed excellent linearity (r2 = 0.9997), precision (%RSD (5,01) = 15%), accurate (80% = %recovery (106,72) = 110%), Limit of Detection (0,1149 mg/L), robust (f calculated = f table), and rugged (t calculated = t table), however Limit of Quantification (0,3482 mg/L) exceeded analyte concentration (0,2125 mg/L). Therefore, the method was declared not valid and can’t be applied as a standard procedure for iron analysis in mine wastewater.