ANALISIS KANDUNGAN KALSIUM, KALIUM, MAGNESIUM, DAN NATRIUM PADA AIR KELAPA HIJAU (Cocos nucifera L. var. viridis)
DENGAN PERBEDAAN TINGKAT KEMATANGAN SECARA SPEKTROFOTOMETRI SERAPAN ATOM
ABSTRAK
Air kelapa mengandung banyak mineral, antara lain kalium, natrium, kalsium, magnesium, besi, tembaga, fosfor, sulfur, dan klorin serta nutrisi lain yang baik untuk tubuh sehingga dapat digunakan dalam meringankan gejala kolera, demam, demam berdarah, batu ginjal, dan hipertensi. Komposisi nutrisi dari air kelapa secara langsung dipengaruhi oleh jenis varietas kelapa dan perbedaan tingkat kematangan buah. Tujuan penelitian ini adalah untuk mengetahui pengaruh tingkat kematangan buah terhadap kandungan kalsium, kalium, magnesium, dan natrium dalam air kelapa.
Sampel yang dianalisis adalah air kelapa hijau dengan tiga tingkat kematangan, yakni sangat muda, muda, dan tua yang berasal dari satu pohon yang sama. Identifikasi kalsium dilakukan menggunakan pereaksi larutan asam oksalat 6,3% dengan penambahan amonium hidroksida; kalium dengan asam pikrat 1% b/v dan uji nyala kawat nikel krom; magnesium dengan pereaksi larutan kuning titan 0,1% ditambah larutan natrium hidroksida; sedangkan natrium menggunakan pereaksi asam pikrat 1% b/v dan dengan uji nyala kawat nikel krom. Penetapan kadar dilakukan menggunakan spektrofotometer serapan atom dengan nyala udara-asetilen. Analisis kuantitatif kalsium, kalium, magnesium dan natrium dilakukan pada panjang gelombang berturut-turut 422,7 nm, 766,5 nm, 589,0 nm dan 285,2 nm.
Hasil identifikasi menunjukkan sampel yang ditentukan mengandung kalsium, kalium, magnesium dan natrium. Hasil penetapan kadar menunjukkan adanya perbedaan kadar kalsium, kalium, magnesium, dan natrium pada air kelapa dari ketiga tingkat kematangan buah yang berbeda. Semakin meningkat kematangan buah, kadar kalsium dan kalium air kelapa semakin menurun. Kadar magnesium dan natrium meningkat dari air kelapa sangat muda ke kelapa muda, lalu menurun kembali pada kelapa tua. Kadar kalsium tertinggi pada air kelapa sangat muda, yaitu 87,41 ± 11,48 mg/l, kadar kalium tertinggi pada air kelapa sangat muda yaitu 624,27 ± 22,09 mg/l, kadar magnesium tertinggi pada air kelapa muda yaitu 27,70 ± 5,67 mg/l, kadar natrium tertinggi pada air kelapa muda yaitu 6,46 ± 0,71 mg/l.
ANALYSIS OF CALCIUM, POTASSIUM, MAGNESIUM, AND SODIUM IN GREEN COCONUT WATER (Cocos nucifera L. var. viridis) WITH
MATURITY DIFFERENCE USING ATOMIC ABSORPTION SPECTROPHOTOMETRY
ABSTRACT
Coconut water contains minerals such as potassium, sodium, calcium, magnesium, iron, copper, phosphorus, sulphur, chlorine and another nutritions which is good for body health so that it can be used to cure fever, dengue fever, urinary stones, and hypertention. Nutritional composition of coconut water is directly influenced by the varieties of coconut and the difference of maturity level of fruit. The purpose of this study was to analyze the influence of maturity level of fruit in concentration of calsium, potassium, magnesium, and sodium in coconut water.
The samples analyzed were green coconuts water with three level of maturities, they were very tender, tender, and mature from the same coconut tree. Identification of calsium performed using oxalic acid reagents mixed with amonium hydroxide; potassium using 1% picric acid reagents and nickel chrome flame test; magnesium using 0.1% titan yellow reagents mixed with sodium hydroxide; while sodium using 1% picric acid reagents and nickel chrome flame test. Quantitative analysis was done using atomic absorption spectrophotometer with acetylene-air flame. Calcium, potassium, magnesium, and sodium were quantitative analyzed respectively at 422.7 nm, 766.5 nm, 589.0 nm dan 285.2 nm wavelength.
The results of identification were concluded that samples contained calcium, potassium, magnesium, and sodium. The results of quantitative analysis showed that the level of calcium, potassium, magnesium, and sodium in coconut water are different among 3 levels maturity of coconut fruit. Raising maturity of coconut fruit will decrease the level of calcium and potassium in coconut water. Raising maturity of coconut fruit will increase the level of magnesium and sodium in coconut water from very tender to tender, then decreasing in mature coconut fruit. The highest calcium level was in very tender coconut water which was 87.41 ± 11.48 mg/l, the highest potassium level was in very tender coconut water which was 624.27 ± 22.09 mg/l, the highest magnesium levels was in tender coconut water which was 27.70 ± 5.67 mg/l, and the highest sodium level was in tender coconut water which was 6.46 ± 0.71 mg/l.
