Sains Malaysiana 37(1): 59-63(2008)

Bahan Sensor untuk Pengesanan pH

Menggunakan Ekstrak Rosel

(Optical Sensing Material for pH Detection based on

the Use of Roselle Extract)

Nurul Huda Abd Karim, Musa Ahmad

Pusat Pengajian Sains Kimia dan Teknologi Makanan

Mohammad Osman, Herman

Pusat Pengajian Sains Sekitaran

Fakulti Sains dan Teknologi

UKM, 43600 Bangi, Selangor D.E. Malaysia

Ahmad Mahir Mokhtar

Fakulti Sains dan Teknologi

Universiti Sains Islam Malaysia (USIM)

Nilai, Negeri Sembilan

Diserahkan:  5 Mac 2007 / Diterima:  6 April 2007

ABSTRAK

Kajian ini menilai potensi ekstrak pewarna kaliks Hibiscus Sabdariffa L. (rosel) sebagai bahan sensor. Dalam kajian ini, sensor pH dibangunkan menggunakan ekstrak warna kemerahan semulajadi dalam kelopak rosel, delfinidin-3-sambubiosida yang dipegunkan dalam kertas turas gentian kaca. Dalam larutan bebas, ekstrak rosel dicirikan menggunakan spektrofotometer UL-nampak untuk mengkaji kesan pH, kepekatan ekstrak, masa ransangan keadaan mantap, analisis kebolehulangan dan analisis kestabilan foto. Ekstrak rosel terpegun dicirikan dengan menggunakan spektrofotometer pantulan untuk mengkaji kesan pH, masa ransangan keadaan mantap, analisis kebolehulangan, analisis kestabilan foto dan kajian histerisis. Hasil kajian menunjukkan bahawa ekstrak bahan semulajadi boleh digunakan sebagai bahan sensor dalam pembinaan sensor optik pH.

Kata kunci: Sensor pH; ekstrak rosel; delfinidin-3-sambubiosida.

ABSTRACT

This research assessed the potential of natural colour extract of Hibiscus Sabdariffa L. (roselle) as sensing material.The pH sensor was developed based on the use of natural reddish colour in roselle’s calyx, delphinidin-3-sambubioside immobilised in a glass fibre filter paper. In free solution, roselle extract was characterised by using UV-visible spectrophotometer to study the effect of pH, extract concentration, response time, repeatability and photostability. The study showed that natural colour extract can be used as sensing material for the development of an optical pH sensor.

Keywords: pH sensor; roselle extract; delphinidin-3-sambubioside

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