Trace analysis of Chromium(VI) ions using acid alumina resin as a filler material column in preconcentration system by off-line method has been carried out. Alumina resin was activated with H2SO4 at pH 1 before being filled to the column. This research showed retention capacity of alumina acid resin was 3.955 mg Cr(VI)/g resin. The analytical performance of this method is good, shown with the limit of detection value was 3.648 µg/L. The reproducibility of this method shown as percentage of coefficient variance was 2.06%. Acid alumina used as resin filler column can increase the signal up to 15.36 times for direct Cr(VI) ions measurement. The accuracy of this method is very good with the recovery percentage value > 95%, shown the matrices of water samples didn’t effect the results of measurements and this method was capable to analyze Cr(VI) ions in water samples at the trace levels.

The research about utilization of nitrogen gas as a carrier gas in the determination of Hg ions by using Cold Vapor-Atomic Absorption Spectrophotometer (CV-AAS

Preparation of the chitosan membrane of ion-selective electrode for determination of cadmium ion has been conducted. Chitosan is a natural polymer containing nitrogen could coordinate with Cd2+ to increase the membrane conductivity value. Chitosan is a principal material and mixed with polyvinylchloride (PVC) as matrix dissolved previously to solvent tetrahydrofuran (THF) and dioctylphenylphosphonate (DOPP) is added as plasticizer by proportion chitosan:PVC:DOPP (6:3:1). To obtain the dopant optimum concentration, membrane was dipped in Cd2+ for 7 days and its conductivity value was measured using the four-point probe method. From FT-IR spectrum the peaks of amine, acetylamide and hydroxy groups wavelength number was observed to assure that Cd2+ bound to the chitosan. The optimum concentration of Cd2+ dopant was obtained at 1.00 M with conductivity value of 549.45 ohm-1m-1 wich gave a Nernstian factor of 32.03 mV/decade with the detection limit of 2.512 x 10-5 M. The electrodes work in the pH range 3 - 7. The life time of the electrode was 8 weeks. The ions of Ni2+, Fe3+, Pb2+, Cu2+, Zn2+, Cl- and SO42- toward concentration range 10-3 M gave response did not interfere in the determine of Cd2+ ion.

Validation method on the determination of Mn in lubricating oil by direct dilution method using Atomic Absorption Spectrophotometer (AAS) in Laboratory & Environment Control PT. Badak NGL Bontang has been done The validation method was done with research stages such as determination of  optimum solvent, and determination of some important parameters influential for validation method such as parameter of liniearitas (r), Instrument Detection Limit (IDL), Methode Detection Limit (MDL), accuracy, precision, Limit of Detection(LOD) and Limit of Quantitation(LOQ). The result of research obtain is good, showed that the linearity value with R2 ≥ 0,997. The IDL and MDL value was 0.0021 ppm and 0.0092 ppm respectively and has been acceptability requirements of MDL. The accuracy paramater obtained recovery value with range 82.25-88.34%. The measurement of repeatability and reproducibility, the CV Horwitz value smaller than % RSD, indicating the method had a good precision. The measurement of  LOD and LOQ value was 0.095 ppm 0.317 ppm respectively. Based on the result of the research determination method of Mn in lubricating oil by direct dilution method using AAS concluded valid.

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ABSTRAKLimbah kulit durian dapat diolah menghasilkan asap cair dan karbon aktif dengan metode pirolisis. Untuk menghasilkan asap cair yang dapat digunakan sebagai pengawet makanan, asap cair perlu di proses dengan metode pemurnian seperti destilasi, pemurnian dengan zeolit aktif dan arang aktif. Hasil karakterisasi asap cair dari kulit durian hasil pirolisis, destilasi, pemurnian dengan zeolit aktif dan pemurnian dengan arang aktif diperoleh nilai pH berturut-turut 4,09; 3,24; 3,46; dan 2,09. Kadar asam asetat berturut-turut 6,07; 7,59; 9,11; dan 10,63 (mg/L). Berdasarkan karakteristik komponen senyawa menggunakan GC-MS asap cair hasil pirolisis terdeteksi 17 senyawa, asap cair hasil destilasi 12 senyawa, asap cair pemurnian zeolit aktif 10 senyawa dan asap cair pemurnian arang aktif 6 senyawa dengan mayoritas komponen senyawa terdiri dari asam asetat, fenol dan karbonil serta tidak mengandung senyawa karsinogenik, sehingga asap cair dari kulit durian dapat digunakan sebagai pengawet makanan.Kata Kunci : Asap Cair, Karbon Aktif, Kulit Durian, Pemurnian ABSTRACTWaste of durian's peel can be used to make liquid smoke and activated charcoal with pyrolysis method. To make liquid smoke for food preservative, liquid smoke must be proceeded with purification method such as distilation, purification with activated zeolit and activated charcoal. Liquid smoke characterization results from the durian's peel from pyrolysis, distillation, purification with activated zeolite and activated charcoal purification with pH values obtained successively 4.09; 3.24; 3.46; and 2.09. Acetic acid levels respectively 6.07; 7.59; 9.11; and 10.63 (mg/L). Based on the characteristics of the component compounds using GC-MS, results of pyrolysis liquid smoke was detected 17 compounds, liquid smoke distillation obtaining 12 compounds, liquid smoke purification with active zeolit obtaining 10 compounds and liquid smoke from activated charcoal purification obtaining 6 compounds with the majority component comprised of acetic acid compounds, phenols and carbonyls and do not contain carcinogenic compounds, so it can be used as a food preservative.

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<p>Penelitian tentang validasi metode penentuan kadar benzena, toluena dan xilena pada sampel udara dan tanah dengan menggunakan kromatografi gas telah dilakukan. Untuk mendapatkan hasil pengukuran yang valid, beberapa parameter penting yang berpengaruh dalam validasi metode telah ditentukan. Beberapa parameter penting yang dilakukan adalah penentuan besaran dasar kromatografi yang meliputi: waktu retensi, kapasitas (k’), faktor selektivitas (α) dan kinerja analitik yang meliputi: penentuan linearitas (r), limit deteksi (LOD), limit kuantitasi (LOQ), presisi dan akurasi. Hasil penelitian penentuan kinerja analitik sangat baik ditunjukkan oleh nilai presisi sebagai % KV &lt; 2/3 nilai KV Horwitz, LOD untuk masing-masing senyawa benzena, toluena dan xilena adalah 0,02 mg/L; 0,59 mg/L dan 0,08 mg/L serta LOQ untuk masing-masing senyawa benzena, toluena dan xilena adalah 0,07 mg/L; 1,99 mg/L dan 0,27 mg/L. Akurasi  metode ini sangat baik ditunjukkan dengan nilai presentase perolehan kembali masing-masing senyawa benzena, toluena dan xilena untuk sampel tanah sebesar 102,61 ± 4,61%; 101,65 ± 7,41%; 102,15 ± 4,15%, dan untuk sampel udara masing-masing senyawa sebesar 101,69 ± 5,77%; 102,08 ± 5,43% dan 98,55 ± 5,11%. Berdasarkan hasil penelitian ini, metode kromatografi gas dapat digunakan dalam penentuan benzena, toluena dan xilena pada sampel udara dan tanah dengan memberikan hasil yang valid.</p><p><strong>Validation Method </strong><strong>o</strong><strong>n The Determination </strong><strong>o</strong><strong>f Benzene, Toluene </strong><strong>a</strong><strong>nd Xylene </strong><strong>i</strong><strong>n Air </strong><strong>a</strong><strong>nd Soil Samples Using Gas Chromatography. </strong>The present study investigated the method for the determination of the content of benzene, toluene, and xylene in air and soil samples using gas chromatography. To obtain a valid measurement result, several important parameters that influence the method validation have been determined. The several important parameters carried out are the determination of the basic chromatographic such as retention time, capacity factor (k'), selectivity (α) and analytical performance measurement includes: the determination of linearity (r), limit of detection (LOD), limit of quantitation (LOQ), precision and accuracy. The result of analytical performance of the research are well verified, in which the value of precision was % CV &lt; 2/3 CV Horwitz value, LOD for benzene, toluene, and xylene compound were 0.02 mg/L, 0.59 mg/L, 0.08 mg/L, respectively, and LOQ for benzene, toluene and xylene compounds was 0.07 mg/L, 1.99 mg/L and 0.27 mg/L respectively. This method achieved high accuration, indicated by a percentage of recovery value of benzene, toluene, and xylene for soil samples of 102.61 ± 4.61%; 101.65 ± 7.41%; 102.15 ± 4.15%, and for air samples was 101.69 ± 5.77%, 102.08 ± 5.43%, and 98.55 ± 5.11% respectively. Based on the results of this research, the method presented in this study can be applied for the determination of benzene, toluene, and xylene using gas chromatography in air and soil samples with valid results.</p>