Analysis of 14C on samples of coral reefs on the Samalona Spermonde Islands vessel through 14C activity measurements using the LSC (Liquid Scintillation Counting) method was carried out. The preparation sample is carried out physically and chemically. Preparation of coral reefs with chemicals using a mixture of 1N NaOH and 30% H2O2 processed with a mixture of 1% HClO4 and 30% H2O2 and finally with 10% HCl to produce a clean sample by adding a weight of 5.36%. Carbonate separation was carried out using KOH as a carbosorb to produce K2CO3 solution. The total carbon is determined by the titration method which produces a total carbon of 0.9984 g. Measurement of 14C activity is done using LSC Hidex 300 SL. Specific activities of coral reef samples obtained were 15.06 ± 3.3613 DPM/gC. Age of coral samples on the island of Samalona in the Spermonde Islands was 130,343 ± 18.4 years

Maming, Maming

Noor, Alfian

Wahyudin, Wahyudin

English

Universitas Hasanuddin: e-Journals

Marina Chim. Acta, Vol. 2 (1), 201924DETERMINATION OF THE AGE OF SAMALONA ISLAND CORAL REEFTHROUGH C-14 ACTIVITY USING LSC METHOD (LIQUIDSCINTILLATION COUNTINGWahyudin*1, Alfian Noor2, and Maming2*1Department of Chemistry, Hasanuddin University,Jl. Perintis Kemerdekaan Km.10, Makassar, Indonesia2Center for Plantation Based Industry, Ministry of Industry,Jl. Prof. Dr. Abdurahman Basalamah No. 28 Makassar*Corresponding author: wahyudinmareppe@gmail.comABSTRACTAnalysis of 14C on samples of coral reefs on the Samalona Spermonde Islands vessel through14C activity measurements using the LSC (Liquid Scintillation Counting) method was carriedout. The preparation sample is carried out physically and chemically. Preparation of coralreefs with chemicals using a mixture of 1N NaOH and 30% H2O2 processed with a mixture of1% HClO4 and 30% H2O2 and finally with 10% HCl to produce a clean sample by adding aweight of 5.36%. Carbonate separation was carried out using KOH as a carbosorb to produceK2CO3 solution. The total carbon is determined by the titration method which produces atotal carbon of 0.9984 g. Measurement of 14C activity is done using LSC Hidex 300 SL.Specific activities of coral reef samples obtained were 15.06 ± 3.3613 DPM/gC. Age of coralsamples on the island of Samalona in the Spermonde Islands was 130,343 ± 18.4 years.Keywords: Samalona Island, Liquid Scintillation Counting (LSC), Activity 14C, Coral ReefReceived: 28 April 2019, Accepted: 30 April 2019,    Published online : 21 May 20191. INTRODUCTIONSamalona is one of the islands in theSpermonde archipelago which is at119o20'33.4" - 119o20'38.3" BT and05o07'27.9" - 05o07'33,2" LS with an areaof 2.34 ha, District Mariso, Makassar City.Data from the results of the MSDC Unhasstudy in 2016 showed that the condition ofcoral reefs on Samalona Island declined,which was around 57% in 2012, to 56% in2013, then 49% in 2014 and droppeddramatically to 35% in 2015 [1]. One ofthe factors that influence coral cover is theenvironmental conditions andcharacteristics of the waters. Somethingsimilar also happened in the parrots ofSamalona. In 2016, the condition of coralreefs on the island of Samalona consistedof three categories, namely bad, mediumand good. The condition of coral cover isas good as 65%, while the condition ofmoderate coral cover is as much as 47%and the condition of bad coral cover is10% with the dominant coral species isAcropora sp.According to [2], almost all islandconstituent materials (± 96%) consist ofrags of coral reefs of various sizes. TheMarina Chim. Acta. 2 (1), pp.24-31, 2019MARINA 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. 2 (1), 201926accumulation of deposited coral reefs if itcontinues continuously will form a barrierreef. According to Darwin's theory thebarrier reef comes from underwatervolcanoes, thus the formation of coralreefs is closely related to the expansion ofthe earth's crust. Determination of the ageof dead coral reefs in a waters hasenormous benefits in studying thegeographic conditions of the origin of thesea coral samples for example to trace andstudy the formation of a rock formation ina beach. In addition, the determination ofthe age of coral reefs can also be used todetermine the age of real radiocarbon seawater [3].The study used the LSC method thathad been carried out, namely in 2001,Yarianto et al. use liquid scintillationcounter to determine the optimalconditions in determining the radioactivityof 32P pest insects. [4], reported theapplication of DEA as an absentee todetermine the age of coral reefs onBarrang Lompo Island by CO2 absorptionmethod using liquid scintillation counter.[5], conducted a study to determine the ageof sediments in Mamuju Waters throughthe LSC method. [6], determines the age ofselayar aquatic reefs using the CO2absorption method using liquid cintillationcounter.In this study, using the method of LSC(Liquid Scintilllation Counting) indetermining the age of the coral reefs ofthe island of Samalona Spermonde Islandsbased on the measurement of 14C activitycontained in the sample. The selected coralreefs are Lobophyllia corymboza becausethey are quite rare in nature. L. corymbozaCoral is a member of the Mussidae familyand is found at a depth of 3-15 meters.2. MATERIAL ANDMETHODMaterialsTimes The materials used are: 6 NHCl, 1 M NaOH, 1 M KOH, 30% H2O2,10% BaCl2, Methyl Orange (MO), 1%HClO4, Phenol Thalein (PP), AqualightLLT, filter paper, distilled water and coralreefs from Samalona Island. Cookingequipment in the form of separatingfunnels, electric stoves, rulers, mortals,gloves, ovens, hammers and glasswarecommonly used in laboratories as well asradiation counters from carbon-14samples, namely LSC Hidex 300 SL.Coral Reef SamplingSampling was carried out on theisland of Samalona. Retrieval at thecoordinates of 119°20'27,695 "BT and05°07'31,974" LS. Sampling of coral reefsfrom the study location using miser, driland hammer.Washing Physics and ChemistryTimes The coral reef samples werewashed in running water and brushedseveral times followed by rinsing withdistilled water until they were clean. Afterphysical washing, a coral sample is placedin a container and dried. Then coral reefsare cut into several small pieces [7].Chemical washing begins withimmersing coral samples into 30% H2O2and 1 N NaOH (1: 1) in a 100 mL beakerand sonicated for ± 10 minutes. Then thewashing solution is separated from thesample with occasional samples brushedand rinsed again with distilled water toremove black stains which are in thenarrowest blemish of the sample.Marina Chim. Acta, Vol. 2 (1), 201927Furthermore, coral reef samples were re-immersed in 30% H2O2 and 1N HClO4 (1:1) in a 100 mL beaker for 30 seconds to 2minutes. The final process in chemicalwashing is a sample of coral reefs soakedin 10 mL of 10% HCl solution for 15-60seconds and rinsing again with distilledwater repeatedly. Furthermore, samples ofcoral reefs were dried in an oven at atemperature of 105 oC to dryness [7].Separation of Carbonate as CO2CO2 analysis in coral reef was carried outas CO2 gas by KOH. The stages inseparating carbonates as CO2 sampleswere carried out by adding HCl 10%  to 10grams of sample powder of coral reefsplaced in a round bottom flask until HCl10%  was used to react with calciumcarbonate in 10 grams of sample. Thereactions that occur between calciumcarbonate and phosphoric acid are asfollows:CaCO3 + 2HCl CaCl2 + CO2 + H2OCO2 produced is flowed into the KOH1 N absorbent solution to produce K2CO3as in the following reaction:2KOH + CO2 K2CO3 +H2OThe scheme of the series of CO2absorption samples of coral reefs can beseen in Figure 1.Figure 1. Design of a carbonate separationtoolDetermination of Total CarbonThe total carbon in the samplesolution (dissolved K2CO3) can becalculated from the carbonateconcentration obtained from the titration ofthe sample solution with HCl. The stagesin the titration process are as much as 5mL of sample solution put into erlenmeyer250 mL then titrated with HCl 5 M, afteradding the MO indicator. Then the samplesolution was taken back as much as 5 mLinto a 250 mL beaker and after that it wasadded with BaCl2 10% until no whitecarbonate precipitate was formed. Thenthe solution is filtered and the filtrateobtained is put into 50 mL erlenmeyer andtitrated with HCl 5 M, after adding the PPindicator.Measurement 14C Activity with LSCHidex 300 SLThe activity of 14C in sample isexpressed in unit disintegration per minute(DPM) of 14C.  The results of sampleenumeration with Liquid ScintillationCounter Hidex 300 SL produced data inCPM units (counts per minute) and TDCR(Triple To Double Coincidence Ratio) orknown as efficiency of enumeration (E).E = CpmDpm x  100%Statistical calculation of radioactivesample using LSC is natural decaycalculation on radioactive elements thatemit pure beta particles at any time orrandom decay.Determination of 14C activity incoral reef can be determined throughenumerating samples with LSC Hidex 300SL. Mixture sample 8 mL and aqualightMarina Chim. Acta, Vol. 2 (1), 201928scintillator 12 mL in vial 20 mL. Then,analysis for 5-1440 minutes. The sameprocedure is done in the background as acomparison.Determined Age of Coral ReefThe age of a coral reef sample can becalculated based on a comparison ofspecific carbon activity (15.3 ± 0.1 dpm/grC) to sample specific activities obtainedfrom enumeration using the radiocarbondecay equation:= t 23. RESULT AND DISCUSSIONPhsycal and Chemical CleaningSampling of Coral ReefSampling of coral reefs was carriedout on Samalona Island, SpermondeIslands. Samalona Island is one of theSpermonde islands which isadministratively located in Mariso District,Makassar.Figure 2. Samalona Island Coral ReefCleaning of Coral ReefIn physical washing, samples of coralreef using running water and rinsing withdistilled water, washing is able to removestains or impurities that are easily lostattached to the surface of coral reefs suchas soil and mud. While the chemicalwashing process that starts from soakingthe sample in a mixture of 30% H2O2 and1N NaOH, is able to remove stains thatstick to the narrowest gaps in the reef. Thesecond immersion sample in a mixture of30% acid-base H2O2 and 1% HClO4 wasable to remove organic residues mixedwith brown / yellow attached to coralpolyps which cannot be used in the firstsoaking. The use of perchloric acid in thesecond immersion can dissolve 5-6% ofthe sample weight. Therefore immersion isonly carried out about 30 seconds up to 2minutes.The final process in chemical washingis the sample soaked in 10% HCl for ± 30seconds. This immersion is done to reducethe CO2 adsorbed on the surface of thesample during the washing process.Table 1. Difference weight of samplesbefore and after the cleaning process.SampleBeforeCleaning(gram)AfterCleaning(gram)Percentageof SampelReduced(%)Coral Reefs(L.Corymboza) 201,430 190,640 5,36 %Separation of Carbonate in SamplesCoral reefs contain calcium carbonate.The carbonate separation process of coralsamples was carried out by adding HCl10% to coral samples which placed into around bottom flask. Reaction occursbetween calcium carbonate and phosphoricacid:CaCO3(s) + 2HCl(l) CaCl2(s) + CO2(gas) + H2O (l)CO2 gas absorbed by the KOHsolution through chemical reaction willproduce dissolved K2CO3 with thefollowing reaction:Marina Chim. Acta, Vol. 2 (1), 2019292KOH(l) + CO2(gas) K2CO3(l) +H2O(l)Determination of Carbon Total inSamplesDetermination of total carbon wascarried out using the titration method using5M HCl. Calculation of total carbon iscarried out in order to determine theweight of the gram of carbon contained inthe sample that will be used in calculatingthe specific activity of carbon-14contained in coral reef samples. Thisspecific activity is the basis for calculatingthe age of the sample. The results ofcalculating total carbon in coral reefsamples is 0.9984 g.Measurement Activity 14C Sample withLSC Hidex 300 SLThe process of measuring 14Cactivity in a coral sample was carried outby enumerating a mixture of 8 mL samplesolution and 12 mL scintillator in a 20 mLvial. Sample enumeration was carried outin 2 stages, namely, the stage ofdetermining the optimum enumerationtime and the stage of determining theaverage enumeration value at the optimumtime.Graph of the DPM value of thesample for the time of counting as shownin Figure 3.Figure 3. Graph of the DPM value of thesample for the time of countingBased on Figure 3, there is a periodicdecrease in DPM over time. However, at180-240 minutes the DPM decrease wasnot significant. The most insignificant orstationary decrease occurred at 210minutes with enumeration efficiency(TDCR) of 0.593, so that the optimumenumeration time was 210 minutes. Thesample is then chopped repeatedly duringthe optimum time. The results of the countat the optimum time were used to calculatethe specific activity of 14C in the sample.The results of enumeration samples at theoptimum enumeration time 210 minuteswith 10 repetitions can be seen in Table 2.Table 2. Data on enumeration results atthe optimum time sample of thecoral reefs of the island ofSamalona, spermonde islandswith LSC Hidex 300 SL deviceswith 10 repetitionsNoChoppingTime(Minutes)Decay Activity(DPM)1 210 443,5402 210 446,7903 210 448,2604 210 448,5005 210 443,3706 210 446,0107 210 437,9808 210 445,4009 210 441,44010 210 442,690Average 444,398Determination of Coral Specific SampleActivitiesThe average specific activity (AS) ofthe sample from the calculation of DPMper unit of carbon mass was obtained at0500100015002 5 15 30 60 90 120 150 180 210 240DPMWaktu (menit)Marina Chim. Acta, Vol. 2 (1), 20193015.06 ± 3.36 DPM / gC. Calculation ofcoral reef specific sample activities can beseen in Annex 7. The average value ofspecific activity of 14C obtained from thesample is smaller than the average specificactivity value of modern carbon standards,which is 15.3 ± 0.1 DPM / gC. Theactivity obtained in the sample shows thatcarbon atom decay takes place everyminute (DPM) in one gram of carbon.Calculation Age of Coral ReefsThe age of coral reef is determinedby comparison with 14C radioactivity fromliving sample or standard (Ao) andRadioactivity 14C in the sample (At).Where :At = Radioactivity of the 14C isotope inthe sampleAo = 14C isotope radioactivity when theplant or animal lives (15.3 ± 0.1)DPM (Libby, 1960)t1/2 = half-life = 5730 ± 50 yearsln 2 = 0.693Based on the calculations performed,the age of the coral reef was around130,343 ± 18.4 years. The standarddeviation value obtained is quite large, thisoccurs because of several factors includingthe process of repeating a small numberand this method is difficult to determine inabsolute terms the measurement of age ofthe sample in the range of tens ofthousands of years.4. CONCLUSIONSBased on the results of research onsamples of the coral reefs of the island ofSamalona Spermonde Islands with themethod of LSC (Liquid ScintillationCounting), conclusions can be drawn:1. The value of the specific activity of 14Con the determination of the age ofSamalona Island's Spermonde Islandcoral reef based on 14C activitymeasurements is 15.06 ± 3.3613DPM/gC.2. The age of Samalona Island'sSpermonde Island coral reef samplebased on 14C activity measurementswas 130,343 ± 18.4 years.REFERENCES[1] Haris, A., 2016, Kelimpahan danDistribusi Isis hippuris di PerairanSpermonde Kota Makassar, JurnalIlmu Kelautan dan Perikanan,1(20): 8-16.[2] Suratno, N., 1994, Peta Geologi danPotensi Bahan Galian NusaTenggara Barat, Skala 1 :250.000, Kantor WilayahDepartemen Pertambangan danEnergi NTB[3] Yuliati, H. dan Akhadi, M., 2005,Radionuklida Kosmogenik untukPenaggalan, PuslitbangKeselamatan Radiasi danBiomedika Nuklir, Pusat RadiasiBatam.[4] Yarianto, S., Susilo, B. dan Sutrisno,S., 2001, Kondisi Optimal untukPenentuan Radioaktivitas SeranggaHama Bertanda P-32 denganMenggunakan Pencacah SintilasiCair, Risalah Pertemuan IlmiahPenelitian dan PengembanganAplikasi Isotop dan Radiasi,Fakultas Teknik, Universitas GajahMada, Yogyakarta[5] Bunga, J.M., Zakir, M., dan Noor, A.,2017, Penggunaan Dietanolaminasebagai Absorben dalam  PenentuanUmur Terumbu Karang di PulauMarina Chim. Acta, Vol. 2 (1), 201931Barrang Lompo KepulauanSpermonde melalui PengukuranAktivitas 14C dengan Metode LSC,Skripsi Tidak Diterbitkan, JurusanKimia Fakultas Matematika danIlmu Pengetahuan Alam UniversitasHasanuddin, Makassar.[6] Tenrisa’na, A., Permatasari, A.,Santoso, Y., Maming, Noor, A.,2017, Analisis 14C dalam SedimenSunai Karema Kabupaten Mamujudengan Metode LSC (LiquidScintillation Counting), ProsidingSeminar Nasional Kimia UNY 2017,Sinergi Penelitian dan Pembelajaranuntuk Mendukung PengembanganLiterasi Kimia pada Era Global.[7] Amri, M., 2018, Penentuan EfisiensiKOH sebagai Carbosorb padaPenentuan Umur Sampel TerumbuKarang Perairan Kepulauan Selayarmelalui Metode LSC, Skripsi tidakditerbitkan, Jurusan Kimia FakultasMatematika dan Ilmu PengetahuanAlam Universitas Hasanuddin,Makassar.[8] Adkins, J.F., Griffin, S., Kashgaria,M., Cheng, H., Druffel, E.R.M.,Boyle, E.A., Edwards, R.L., danShen, C.C., 2002,  RadiocarbonDating of Deep-Sea Corals, ArizonaBoard of Regents on Behalf of theUniversity of Arizona, 44(2): 567-580

DETERMINATION OF THE AGE OF SAMALONA ISLAND CORAL REEF THROUGH C-14 ACTIVITY USING LSC METHOD (LIQUID SCINTILLATION COUNTIN

Marina Chimica Acta

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DETERMINATION OF THE AGE OF SAMALONA ISLAND CORAL REEF THROUGH C-14 ACTIVITY USING LSC METHOD (LIQUID SCINTILLATION COUNTIN

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