LABORATORY STUDIES ON THE FATE OF THE VETERINARY ANTIBIOTIC DOXYCYCLINE DURING THE STORAGE OF LIQUID PIG MANURES AND DIGESTATES

HANNA RESTI KARTIKA AYU SUWITO, Prof. Dr. Endang Tri Wahyuni, M.S.

2014 | Tesis | S2 Ilmu Kimia

Studi laboratorium mengenai kestabilan antibiotic doksisiklin selama penyimpanan pada sampel liquid pig manure dan residu fermentasi telah dilakukan. Simulasi studi penyimpanan dilakukan dengan masa inkubasi selama 170 hari untuk sampel manure dan 120 hari untuk residu fermentasi dengan terminasi interval masing-masing pada hari ke-0, 7, 35, 84, 120 dan 170. Metode analisis residu digunakan untuk memproses sampel sebelum tahap analisis. Identifikasi dan kuantifikasi senyawa-senyawa target dianalisis menggunakan liquid chromatography tandem mass spectrometry dengan electrospray ionization mode positif sebagai sumber ionnya (LC-(ESI+)-MS/MS). Efek matriks dan epimerisasi yang terjadi juga dipelajari sebagai data pendukung. Hasil tes simulasi menunjukkan bahwa konsentrasi doksisiklin menurun hingga 39% atau sekitar 19,5 mg/kg setelah 170 hari pada sampel liquid pig manure, sedangkan doksisiklin tersisa 32% atau sekitar 6,4 mg/kg setelah 120 hari untuk sampel residu fermentasi. Efek matriks ditemukan baik pada manure maupun residu fermentasi untuk doksisiklin, demeklosiklin dan tetrasiklin. Pada uji epimerisasi diketahui bahwa suhu penyimpanan, paparan cahaya dan penambahan asam dapat meningkatkan pembentukan epimer.

The laboratory studies on the fate of doxycycline during storage of liquid pig manures and digestates was investigated. The storage tests were conducted to investigate the behavior of doxycycline during storage in manure as well as digestate. The incubation period was 170 days for manure and 120 days for digestate samples with the termination interval of 0, 7, 35, 84, 120 and 170 days. Residue analysis method was carried out to treat the samples prior to analysis. The identification and quantification of the target compounds were performed using liquid chromatography tandem mass spectrometry with electrospray ionization in positive mode (LC-(ESI+)-MS/MS). Moreover, the epimerization and matrix effects were studied additionally. The results show that doxycycline remained about 39% or 9.5 mg/kg within 170 days storage in liquid pig manures. As for digestate samples, the concentration of doxycycline dropped to 32% or 6.4 mg/kg after 120 days. Matrix effects were observed in both manure and digestate samples for doxycycline, demeclocycline and tetracycline. Moreover, the results of epimerization studies indicated that the storage temperature, exposure of light and addition of acid could accelerate the degree of epimerization.

Kata Kunci : manure, residu fermentasi, doksisiklin, LC-(ESI+)-MS/MS