#TITLE_ALTERNATIVE#

• Main Author: AGUSTINI KOESMAWATI ( NIM : 30509007); Pembimbing : Prof. Dr. Buchari ;Prof. Dr. Slamet Ibrah, TINY
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/19564
• Institution: Institut Teknologi Bandung

Reference material (RM) is a material or substance one or more of whose property values are sufficiently homogeneous and stable for a certain period of time. RM is used in testing laboratory to ensure accuracy of analysis results, method validation of analysis, calibration of an apparatus, measurement of equipment <br /> <br /> <br /> performance, method development of analysis, improvement of existing methods, the creation of a secondary reference material, performance test for analyst or <br /> <br /> <br /> technician and for quality control test results or to make a quality control chart. Up to now, the certified reference materials are still imported at an expensive <br /> <br /> <br /> price with limited matrices types. This research was conducted a preparation of candidate reference material in tuna fish by following the stages of preparation of <br /> <br /> <br /> the reference material based on ISO 34 and the IAEA, which was started from the selection matrix, sample preparation, characterization, evaluation, homogeneity <br /> <br /> <br /> testing and stability testing. Type of tuna used in this research was a yellowfin species (t. albacares) and which was caught from Muara Baru, Jakarta. After being caught, the tuna samples were put into a cooler box and sent directly to Bandung. The tuna meat was taken from the back part of the body using ceramic knife and then put it in a plastic bag, and then stored in the refrigerator. Tuna fish fillet was weighed, and cut into small pieces, dince, and then stored in a freezer for 24 hours. Frozen sample was freeze dried for 24 hours. The sample was then crushed, sifted using 250 &#956;m sieve (equivalent to 60 mesh). The smaller particle size of the samples which passed to the sieve were weight of approximately 1-2 g, pur into brown sample bottle and then closed tightly. The sample bottles were placed inside sealed plastic bags with silica gel. Arsenobetaine (AB) is the major organic arsenic species in tuna fish sample. AB is very difficult to decompose into arsenate form, so it may need special sample preparation techniques. This research was conducted the development of four methods of sample preparation. <br /> <br /> <br /> The first method was wet destruction with the addition of nitric acid and peroxide, and then was heated using a microwave oven conventional (ADMC). The second sample preparation method was dry ashing digestion with the addition of a mixture of MgO and Mg (NO3)2 slurry without addition of reducing solution (DKTP). The third and fourth methods were dry ashing digestion with the addition of a mixture of MgO and Mg (NO3)2 slurry, followed by the addition of a reducing solution wich have different volume ratios (DK-P1 and DK-P2). The heating process of the sample is carried out in stages, firstly 16 hours at the temperature of 80 oC inside an oven, followed by 1 hour at 200 oC, 1 hour at 300 oC, and 8 hours at 500 oC inside a muffle furnace. After cooling, the samples were dissolved by hidrochloric acid, and the was added of 10 ml mixture solution of 2M HCl 15% KI, and 15% ascorbic acid of 5:1:2 v/v/v, and then warmed for 10 minutes at 40-50 oC. To determine the method of preparation that can provide the highest and approaching 100% recovery, a curve of comparation of <br /> <br /> <br /> concentration value from HG-QFAAS method experiment and standar method of ICPMS against the repetition of analysis was made. The recovery value obtain from ADMC, DK-TP, DK-P1 and DK-P2 method was 2.4 %, 47 %, 85 % and 92 %, respectively. DK-P2 gave the highest and best approaching of 100 % recovery,so DK-P2 method preparasi was chosen for characterization of candidate reference material. Method validation of HG-QFAAS was carried out by measuring the linearity, LoD, LoQ, accuracy, and precision. The total arsenic concentration in candidate reference material sample was 3.28 ± 0.14 &#956;g g-1. The <br /> <br /> <br /> linearity was drawn from AsO3 3- standard solution concentration of 0 - 7 ng g-1, the regression line equation was y = 0.0048x + 0.0002 and the correlation <br /> <br /> <br /> coefficient was 0.998. The LoD and LoQ value were 0.0564 and 0.188 ng g-1, respectively. The measurement bias was 0.51 &#956;g g-1, and percent recovery value was 86.52%. The method precision was calculated as RSD value was 6.43% and HorRat value was 0.48. Homogeneity testing was conducted using 14 sample bottle which was chosen by random number. The measurement of sample homogeneity was conducted using ICP-MS. The candidate reference material was declared homogeneous according to the statistical calculation of the ANOVA, with Fcalculation value was 3.71, this value was smaller than Fcritical value of 4.75. <br /> <br /> <br /> The candidate reference material was also homogenous at second criterion homogeneity test. Stability testing of candidate reference material was conducted for 12 months at room temperature storage and it was measured for interval 2 months. The stability testing was done using two different measurement methods, namely HG-QFAAS and ICP-MS. The total arsenic concentration in the candidate reference material sample for 12 months storage, gave the line regression of y = 0.002x + 3.473. The bias of total arsenic concentration after being storaged for 12 months was 0.93%. The deviation value was still in the accepted range compared to general laboratory measurement tolerance value of 2%. From the research results, it could be concluded that the candidate materials reference was stable on the 12-month at room temperature storage. Two sample preparation methods were compared, namely water extraction and acid destruction, followed by ICPMS measurement. Destruction was compared to extraction method and the linear equation from the curve was y = 1.040x with correlation coeficient value was 0,9986. Another curve was shown that the linear regression equation of extraction and destruction methods were y = 0,957x and y = 0,996x, respectively. <br /> <br /> <br /> The correlation coeficient of extraction and destruction methods were 0,9992 and 0,9999, respectively. Acid destruction method was found to be the best sample <br /> <br /> <br /> preparation method for ICP-MS measurement. The arsenic species was identified by HPLC using cation exchange column Chrompack-Ionosphere 5C, Pyridine pH 2.3 mobile phase, flow rate 1.0 L/minutes, and detector ICP-MS. AB in candidate reference material and CRM DORM-2 peaks were found in 160 second. <br /> <br /> <br /> According to ILAC G:12, the candidate reference material which was made in this research was categorized as A type of reference materials (chemical composition), <br /> <br /> <br /> subsection 4 (environmental reference materials), sub sub section 5 (marine: fish trace elements), so the candidate reference material was categorized as reference material type A4.5. The candidate reference material can be used for total arsenic measurement using HG-QFAAS, and ICP-MS. Reference materials preparation <br /> <br /> <br /> from popular or export commodities have good prospect in the future.