The work is to determine absorption capacity, optimum time analysis, efficiency enumeration (TDCR), specific activityof 14C and coral age. Steps taken are physical and chemical washing, CO2 absorption, and analysis using liquid scintillation counter Hidex 300 SL. Due to washing, the weight loss was 4.74%. Total carbon absorbed was 1,056 grams. CO2 absorption capacity using KOH was 47% while optimum time analysis by LSC was 30 minutes and average efficiency enumeration (TDCR) was 0.6877.  It was concluded that specific activityof 14C was 14.7361 DPM/gC and coral age in Kayangan Island was 310.49 years

Firman, Nur Faiizah

Gaffar, Maming

Noor, Alfian

Yusuf, Syafyuddin

Zakir, Muhammad

English

Marina Chimica Acta

Marina Chim. Acta, Vol. 19 (2), 201866ANALYSIS ACTIVITY 14C OF CORAL REEF IN KAYANGAN ISLANDNur Faiizah Aqiilah Firman1, Alfian Noor2*, Muhammad Zakir2, Maming2,Syafyuddin Yusuf31Doctoral Program of Chemistry, Faculty of Mathematics and Natural Sciences, HasanuddinUniversity, Makassar, Indonesia, 902452 Chemistry Department, Faculty of Mathematics and Natural Sciences, Hasanuddin University,Makassar, Indonesia, 902453Marine Science Department, Faculty of Marune Science and Fisheries, Hasanuddin University,Makassar, Indonesia, 90245*Corresponding author: alfiannoor744@gmail.comABSTRACTThe work is to determine absorption capacity, optimum time analysis, efficiency enumeration(TDCR), specific activity of 14C and coral age. Steps taken are physical and chemical washing, CO2absorption, and analysis using liquid scintillation counter Hidex 300 SL. Due to washing, the weightloss was 4.74%. Total carbon absorbed was 1,056 grams. CO2 absorption capacity using KOH was47% while optimum time analysis by LSC was 30 minutes and average efficiency enumeration(TDCR) was 0.6877.  It was concluded that specific activity of 14C was 14.7361 DPM/gC and coralage in Kayangan Island was 310.49 years.Keywords: Coral reef, Kayangan Island, radiocarbon dating, LSCReceived : 4 November 2018, Accepted : 14 November 2018,    Published online : 17 November 20181. INTRODUCTIONSpermonde archipelago have a highmarine biodiversity, divided into 4 zonesstretching from north to south. The firstzone, closest to coastline of SulawesiIsland, with average depth 10 m. Secondone, about 5 km from the coastline ofSulawesi Island, with an average depth of30 m. The third one, starting from 12.5km from the coastline of Sulawesi withdepth of 20-50 m. The fourth zone with adistance of 30 km from the mainland ofSulawesi. Kayangan Island is in innerzone with an area 2,6 ha [1][2][3][4].Examination of ecological changesand evolution in the context ofenvironmental variability provides anideal framework for understanding coralreef paleoecology [5]. Age of coral reefscan be known by using radiocarbondating. Measurement of coral age basedon isotope 14C activity contained incalcium carbonate of coral skeleton[6][7].Metering activity 14C use LiquidScintillation Counter (LSC). LSC detectand measure particle β- emission releasedby a sample containing 14C [8]. LSCHidex 300 SL has advantage formeasurement activity of 14C. LSC Hidex300 SL has automatic TDCR or efficiencyenumeration without external or internalstandard sources. Mensuration efficiencyenumeration with TDCR (triple to doublecoincidences) allows determinationMarina Chim. Acta. 19 (2), pp. 66-72, 2018MARINA CHIMICA ACTAJurnal Tiga Bahasa Tentang Kimia LautOpen Access Journall at : http//journal.unhas.ac.id/index.php/mcap-ISSN : 1411-2132e-ISSN : 2620-6145Marina Chim. Acta, Vol. 19 (2), 201867activities for radionuclides pure beta-emitting with high accuracy. Quench ishandled directly by TDCR [9].Preparation sample method formeasuring 14C activity is CO2 absorption.This method quick, inexpensive, simpleand requires less carbon [10]. Thesolution used as absorbent is potassiumhydroxide. Potassium hydroxide absorbCO2 that produces potassium carbonate[11]. Therefore this study was conductedto analyze 14C activity and age of coralreef.2. MATERIAL ANDMETHODLocationCoral reef was sampled in KayanganIsland waters (Figure 1) and kept inRadiation Chemistry Laboratory.Figure 1. Kayangan Islands (GoogleTMDigitalGlobe)Coral Reef SamplingTools and material used in samplingare sample bag, shovel, crowbars, and coolbox for sample stored. Sampling coral reefused snorkeling equipment. Coral reefsampling method used crowbar and shovelwith depth 3-5 m from sea level. Type ofdead coral reef is Styllophora pistillata.Physics and Chemical WashingWashing sample divided in twostages; physical washing and chemicalwashing. Its aim to eliminatecontamination found on the surface of thecoral. Sample was washed with water andbrushed several times until clean. Afterphysical washing, sample of coral wasplaced in container and dried [12].Coral was immersed in a mixture ofH2O2 30% and NaOH 1N ratio of 50:50 ina 100 mL beaker. Then, washing solutionwas separated from the sample withoccasional sample being brushed andrinsed again with distilled water to removethe black stain on the sample's narrowestblemish. Furthermore, sample of wasimmersed in a mixture of H2O2 30% andHClO4 1% with ratio 50:50 in a 100 mLbeaker for 30-120 seconds. Sample wasseparated from washing solution andrinsed ± 3 times with distilled water. Thelast process in chemical washing was thatsample of coral reef was soaked in 10 mLof HCl 6N solution for 15-60 seconds andrinsed ± 3 times with distilled water. Then,sample was dried in oven at 60 °C untildry and weighed to find out weightpercentage sample lost during chemicalwashing process [12]. Then, sample wascooled and crushed using mortar tobecome powder [13].CO2 Absorption [13]Sample of coral reef was weighed5 gram and put into a round bottom flask.N2 High Purity Gas (HP) was flowed toCO2 absorption devices. Sample wasadded HCl 10 % until calcium carbonatereacted. The CO2 gas produced was flowedthrough acid absorber and water absorberto CO2 absorption column. In this reactionCO2 would be produced through thefollowing reactions:Marina Chim. Acta, Vol. 19 (2), 201868CaCO3 + 2HCl CaCl2 + H2O + CO2After the absorption process wascomplete, solution formed put into thereservoir flask for the next stage. The CO2absorption tool scheme can be seen inFigure 2.Figure 2. Design CO2 Absorption Toolof Coral Reef SampleWhere 1). N2 gas, 2). Sample, 3). HCl10%, 4). Acid Absorber, 5). WaterAbsorber, and 6). CO2AbsorberDetermination of Total CarbonCarbonate solution was pipetted 5mL and put into a 50 mL Erlenmeyer.Then, it was titrated with HCl and uses theMO indicator. The second carbonatesolution was added with BaCl2 10% andfiltered. Filtrate was pipetted 5 mL and afew drops of PP indicator, then titratedwith HCl 5M. The difference betweenvolume of first titration and secondtitration was used to determine totalcarbon contained in the sampleSample and Marble (Background)Analysis Using Liquid ScintillationCounter (14)Activity 14C in the sample isexpressed in units of activity, which is thedecay every minute (DPM) of 14C. Theresults of the sample enumeration withLSC Hidex 300 SL enumerators producedata in units of CPM (counts per minute)and TDCR (Triple to Double CoincidenceRatio) or known as enumeration efficiency(E), Equation 1:E = CpmDpm x 100 % (1)The statistical calculation of theradioactive sample enumeration using LSCis a very natural decay calculation inradioactive elements which emit pure βparticles at random (random decay).Determination of 14C activity in coralreef samples can be known through sampleenumeration with LSC Hidex 300 SL.Mixture sample solution 8 mL andscintillator 12 mL into a 20 mL glass vial.Homogeneous sample mixture andscintillator were analysis with LSC Hidex300 SL device with a counting time of1-240 minutes. The same was done forbackground counting by filling 8 mL ofbackground solution and 12 mL ofscintillator into a 20 mL vial and choppedwith LSC Hidex 300 SL.Calculate Age of Coral ReefThe age of coral reef samples can becalculated based on the comparison ofmodern carbon-specific activities (15.3 ±0.1 DPM/g C) to the specific activity ofthe samples obtained from the resultanalysis using the radiocarbon decay rateequation 2:t = t1/2ln 2 lnAoAt (2)Where:t = Sample aget1/2 = half-life isotope 14C (5730 ± 40years)At = isotope 14C activity of sampleAo = isotope 14C activity on same materialwhen plant/ animal livesLn2 = 0,693Marina Chim. Acta, Vol. 19 (2), 2018693. RESULT AND DISCUSSIONPhsycal and Chemical WashingPhysical washing, sample of coralreef is brushed and washed to dissolvesediment attached to coral reef. Chemicalwashing with mixture H2O2 30% andNaOH 1N in sonication aims to removeblack crust/ strains attached to the narrowgap or between septa of the coral reef.Washing wit mixture H2O2 30% andHClO4 1% which effectively removes theremaining stains that are still attached tothe sample. The last stage, washing withHCl 6N for 15-60 minutes, separating itwith solution and rinsing it several timeswith distilled water [12]. This processremove about 4,74 % total coral weight(Table 1).Determination of Total Carbon andAbsorption CapacitySample of coral reef was crusheduntil smooth. Then, solution of HCl 10%is added. The reaction of calciumcarbonate with HCl produces CO2 gas.CO2 gas passes through the absorbent acidwhich contains AgNO3 which functions toabsorb acid; absorbent water containingsilica gel. Then, it passes through the KOHsolution which functions as a CO2absorber. The reaction of CO2 gas withKOH can be seen in reaction:CO2(g) + 2 KOH(aq) K2CO3(aq) + H2O(aq)The process of CO2 absorption byKOH, not all of them can be absorbed,which is marked by producing bubbles. Tofind out the amount of CO2 absorbed usingacidimetric titration. In Table 2, based onthe weight of CO2, KOH absorptioncapacity or percentage of KOH's ability toabsorb CO2 gas produced from coral reefsamples can be known.Table 2. CO2Weight and Absorption Capacity of KOHMeasurement of samples containing14C uses CO2 direct absorption method.This method converts the sample to CO2which can be analyzed using LiquidScintillation Counter Hidex 300 SL. Betaactivity in the sample associated withdecay 14C and compared with background[15]. Sample enumeration is carried out inAbsorbent Amount of CO2Weight of CO2 (g) Absorption Capacity (%)KOH 1,0560 47Table 1. Percentage of Remove of total Coral WeightSample Before Washing (g) After Washing (g) % Remove of totalCoral WeightCoral reef 947,444 900,312 4,74 %Marina Chim. Acta, Vol. 19 (2), 2018702 stages: the first determine optimum timeof enumeration (Figure 3) and the seconddetermine average enumeration inoptimum time (Table 3).Figure 3.. Optimum Time of Enumeration.Table 3. Average Enumeration in Optimum TimeNo Enumeration Time (m) CPM DPM TDCR1 30 318,030 427,080 0,7442 30 317,460 454,950 0,6973 30 301,660 442,490 0,6814 30 301,720 444,840 0,6785 30 304,560 450,450 0,6766 30 293,250 437.690 0,6707 30 300,520 449,290 0,668Average 305,3142 443,8271 0,6877Based on the data in graph 1, DPM(disintegration per minute) in the 5thminute increased and in the 15th minute itdecreased. Enumeration began to stabilizeat 30 minutes. Instability enumerationvalue can be caused by 3 phenomena arechemical quenching, ionization quenching,and color quenching. Chemical quenchingcan be caused by chemical substancescontained in the sample, which can reducetransfer energy process. Ionizationquenching related to density excitedsolvent molecules. Color quenching,phenomenon that occurs when visiblesample is analyzed, which will absorbphotons in the form of light before beingdetected by PMT [11].Age of Coral Reef in Kayangan IslandSpecific activity of sample isobtained from the difference in sampleDPM and the background DPM divided bythe total carbon sample, where marble asbackground (Tabel 4).The age of a coral reef sample can bedetermined by comparison between480.000490.000500.000510.000520.000530.000540.000550.000560.0000 50 100 150 200 250 300DPMEnumeration Time (m)Marina Chim. Acta, Vol. 19 (2), 201871specific activity of modern carbon and thespecific activity of sample obtained fromequation (3). In Table 5, there is anaverage enumeration efficiency, specificactivities and estimated age of coral reefsamples.Table 4. Specific Activities 14C of Sampleand BackgroundNo DPMs DPMb DPMk DPM/gC1 427,080 419,650 7,43 7,03592 454,950 423,930 31,02 29,3753 442,490 426,900 15,59 14,76324 444,840 431,580 13,26 12,55685 450,450 431,970 13,64 12,91666 437.690 429,070 8,62 8,16287 449,290 429,920 19,37 18,3428Average 14,7361Table 5. Age of Coral ReefNo Analysis TDCR14CActivity Age1 Coral reef 0,6877 14,7361 310,49954. CONCLUSIONSBased on the research, it can beconcluded that the absorption capacityKOH was 47 %. Specific activity coralreef was 14,7361. Age of coral reef speciesStyllophora pistillata in Kayangan Islandwas 310,4995 years.ACKNOWLEDGEMENTSThe research was funded bya PMDSU scholarship from the Ministryof Research and Technology-Indonesia in2018. The authors would like to thank forall those have assisted this research.REFERENCES[1] Nurdin, A., Komatsu, T., Rani, C.,Supriadi, Fakhriyyah, S., Agus,2016, Coral Reef Destruction ofSmall Island in 44 Years andDestructive Fishing in SpermondeArchipelago, Indonesia, EarthEnviron. Sci., doi:10.1088/1755-1315/47/1/012011.[2] Melawaty, L., Noor. A., Harlim, T.,Voogd, N. D., 2014, Essential MetalZn in Sponge Callyspongia aerizusafrom Spermonde Archipelago,Advances in Biological Chemistry,4:86-90.[3] Muller, E. M., Raymundo, L. J.,Willis, B. L., et al., 2012, CoralHealth and Disease in the SpermondeArchipelago and Wakatobi,Sulawesi, . J. Indonesia Coral Reef,1(3): 147-159.[4] Kench, P. S. dan Mann, T., 2017,Reef Island Evolution and Dynamic:Insights from the Indian and PacificOceans and Perspectives for theSpermonde Archipelago, Frontiersin Marine Science, 4(145), doi:10.3389/fmars.2017.00145.[5] Pandofili, J. 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ANALYSIS ACTIVITY 14C OF CORAL REEF IN KAYANGAN ISLAND

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ANALYSIS ACTIVITY 14C OF CORAL REEF IN KAYANGAN ISLAND

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