Variasi Komposisi Eluen pada Isolasi Steroid dan Triterpenoid Alga Merah Eucheuma cottonii dengan Kromatografi Kolom Basah

Steroid and triterpenoid compounds in petroleum ether fractions of red algae Eucheuma cottonii were isolated by slurry column chromatography. Isolation was started with maceration extraction using methanol solvent. The methanol extract was hydrolyzed with HCl 2 N and partitioned using petroleum ether solvent. The presence of steroid and triterpenoid was determined by phytochemical test using Lieberman Burchard reagent. Petroleum ether fraction was separated by slurry column chromatography with the variation of eluent composition n-hexane: ethyl acetate 16:4; 17:3; 18:2. The isolates were monitored by analytical thin-layer chromatography (TLC) and the best result was identified using FTIR. Percent yields of methanol extract and petroleum ether fraction were 11.866% and 8.03%, respectively. The optimum eluent composition in column chromatography for separation was n-hexane : ethyl acetate (18:2) obtained 2 steroid and 3 triterpenoid fractions. FTIR analysis gives information about functional groups of –OH, C=C, C-O, CH2, -C(CH3)2forsteroids and functional groups of –OH, C=O, C=C, CH2, -C(CH3)2 for triterpenoid.Keywords: Eucheuma cottonii, column chromatography, steroid, triterpenoid, variation of eluent composition Senyawa steroid dan triterpenoid dalam fraksi petroleum eter alga merah Eucheuma cottonii telah diisolasi menggunakan kromatografi kolom basah. Isolasi dilakukan dengan cara ekstraksi maserasi menggunakan pelarut metanol. Ekstrak pekat metanol dihidrolisis dengan HCl 2 N dan dipartisi menggunakan pelarut petroleum eter. Senyawa steroid dan triterpenoid diuji fitokimia menggunakan reagen Lieberman Burchard. Fraksi petroleum eter dipisahkan menggunakan kromatografi kolom basah variasi komposisi eluen n-heksana:etil asetat dengan perbandingan 16:4; 17:3; dan 18:2. Hasil isolasi dimonitoring menggunakan kromatografi lapis tipis (KLT) analitik. Hasil monitoring yang terbaik diidentifikasi gugus fungsinya menggunakan FTIR. Hasil penelitian menunjukkan rendemen ekstrak metanol dan fraksi petroleum eter masing-masing sebesar 11,866% dan 8,03%. Pemisahan kolom dengan variasi komposisi eluen n-heksana:etil asetat terbaik adalah 18:2 dengan diperoleh 2 kelompok fraksi steroid dan 3 kelompok fraksi triterpenoid. Hasil analisis FTIR pada isolat steroid memberikan informasi gugus –OH, C=C, C-O, CH2, -C(CH3)2, sedangkan isolat triterpenoid memberikan informasi gugus –OH, C=O, C=C, CH2,-C(CH3)2. Gugus gem dimetil (-C(CH3)2)merupakan ciri khas rantai samping steroid ataupun triterpenoid.Kata kunci: Eucheuma cottonii, kromatografi kolom, steroid, triterpenoid, variasi komposisi eluen

Elution Is a Critical Step for Recovering Human Adenovirus 40 from Tap Water and Surface Water by Cross-Flow Ultrafiltration

ABSTRACTThis paper examines the recovery of the enteric adenovirus human adenovirus 40 (HAdV 40) by cross-flow ultrafiltration and interprets recovery values in terms of physicochemical interactions of virions during sample concentration. Prior to ultrafiltration, membranes were either blocked by exposure to calf serum (CS) or coated with a polyelectrolyte multilayer (PEM). HAdV 40 is a hydrophobic virus with a point of zero charge between pH 4.0 and pH 4.3. In accordance with predictions from the extended Derjaguin-Landau-Verwey-Overbeek theory, the preelution recovery of HAdV (rpre) from deionized water was higher with PEM-coated membranes (rprePEM= 74.8% ± 9.7%) than with CS-blocked membranes (rpreCS= 54.1% ± 6.2%). With either membrane type, the total virion recovery after elution (rpost) was high for both deionized water (rpostPEM= 99.5% ± 6.6% andrpostCS= 98.8% ± 7.7%) and tap water (rpostPEM= 89% ± 15% andrpostCS= 93.7% ± 6.9%). The nearly 100% recoveries suggest that the polyanion (sodium polyphosphate) and surfactant (Tween 80) in the eluent disrupt electrostatic and hydrophobic interactions between the virion and the membrane. Addition of EDTA to the eluent greatly improved the elution efficacy (rpostCS= 88.6% ± 4.3% andrpostPEM= 87.0% ± 6.9%) with surface water, even when the organic carbon concentration in the water was high (9.4 ± 0.1 mg/liter). EDTA likely disrupts cation bridging between virions and particles in the feed water matrix or the fouling layer on the membrane surface. For complex water matrices, the eluent composition is the most important factor for achieving high virion recovery.IMPORTANCEHerein we present the results of a comprehensive physicochemical characterization of HAdV 40, an important human pathogen. The data on HAdV 40 surface properties enabled rigorous modeling to gain an understanding of the energetics of virion-virion and virion-filter interactions. Cross-flow filtration for concentration and recovery of HAdV 40 was evaluated, with postelution recoveries from ultrapure water (99%), tap water (∼91%), and high-carbon-content surface water (∼84%) being demonstrated. These results are significant because of the very low adenovirus recoveries that have been reported, to date, for other methods. The recovery data were interpreted in terms of specific interactions, and the eluent composition was designed accordingly to maximize HAdV 40 recovery.