Browsing by Author "Khalid, Reem Saadi"

Analysis of arsenic (As), mercury (Hg), cadmium (Cd) and lead (Pb) in herbal medicinal products (HMP) encounter significant analytical challenges. This study aimed to develop, optimize and validate an analytical method for the determination of As, Hg, Cd and Pb in HMP using atomic absorption spectrometer (AAS). To overcome the limitations of hydride generation (HGAAS) and cold-vapor (CVAAS) techniques graphite furnace (GFAAS) was developed for the detection of As and Hg. The technique showed consistent levels of accuracy and precision in spiked HMP samples for As and Hg. The recoveries of arsenic measured by HGAAS – GFAAS were ranged between 81.3-91.5 % and 82.7-93% respectively. Mercury recoveries measured by CVAAS-GFAAS were ranged between 81.7-86.6 % and 80-86.7%. Sample preparation methods were developed by comparing three methods namely WD1, WD2 and WD3 which represented acid digestion with mixture of nitric-hydrochloric acids HNO3 – HCl in a ratio of 1:3 using conventional open vessel heating program, mixture of nitric acids - hydrochloric HNO3 – HCl in a ratio of 1:3 and a mixture of HNO3-H2O2 in a ratio of 4:1 using close vessel microwave digestion respectively. The comparison was conducted on HMP spiked with various concentrations of As, Hg, Cd and Pb standard solutions. Recoveries of As were 78.1-82.3 % , 90.5-92.8% , 91.4-93.3%; Hg 74.2-82.1, 87.1-91.9, 86.2-91.4; Cd 81-85,88.2-93.4,87.7-93.5 and Pb 78.1-82.2, 88.1-90.9, 88.7-92.6 for WD1,WD2 and WD3 respectively. The statistical analysis indicated good recoveries by microwave digestion methods WD2 and WD3 compared to method WD1 as they had given a significant high recoveries (p<0.05) compared to methodWD1. In further study to evaluated the effect of ammonium dihydrogen phosphate (NH4H2PO4) and palladium nitrate Pd (NO3)2 on the recovery values of As and Hg by comparing three digestion methods namely M1, M2 and M3 that represent microwave digestion without stabilizers addition, with addition of NH4H2PO4 and with addition Pd (NO3)2 respectively. Recoveries of As were ranged between 88.5-90.8%, 90-93.7%, 96.1-104% and Hg 88.3-91.8% ,87.4-93.5%, 95.5-100.1% for M1,M2 and M3 respectively. Statistical analysis showed significant high recoveries (p<0.05) for M3 compared to M1 for As and Hg analysis. Optimization of three digestion factors namely A, B and C time of digestion, reagent volume and temperature at high and low levels was performed by design of experiments (DOE) statistical approach. The optimum recoveries for As, Hg, Cd and Pb where found when factor A and C were at high level and factor B was low level. The developed method was validated by the analysis of As, Hg, Cd and Pb in apple leaves 1515 standard reference material (SRM) and applied for the analysis of some commercial HMP samples available in Malaysia. Excellent recoveries were obtained ranged between 98.2-102% for SRM. As was detected in 35%; Hg was found in 60%; Cd was found in 55% and Pb was found at 65% of the total number of the samples.

Traditional medicine (TM) is the oldest form of health care style known to humanity; it has been used in different cultures throughout the history. According to the World Health Organization (WHO) reports, more than 70% of the world population use TM. The broad use of TM is often attributed to the accessibility, affordability and availability of such products to the majority of the world`s population. Asians are well-known for their reliance on TM. Malaysia has a long tradition and rich legacy from three main cultural groups (Malay, Chinese and Indian) of using TM, a large section of the population in this country is depending on TM for their healthcare needs. The huge demand for TM in Malaysia has significantly increased the Malaysian TM market from US$ 385million in 2000 to US$ 1.29 billion in 2005. Due to the global wide diffusion of TM the safety, efficacy and quality control of such products became significant concern from various health institutes. Presence of toxic substances such as heavy metals is often reported in TM products. This study has been initiated with a prime focus of detecting the amount of heavy metals namely arsenic (As), cadmium (Cd), lead (Pb), nickel (Ni), zinc (Zn) and iron (Fe) in locally available traditional medicines both registered and unregistered medicinal products in various dosage forms from the East Coast region of Malaysia. The determination of Zn and Fe were conducted using Flame Atomic Absorption Spectrometer (FAAS), while Pb, Cd and Ni analysis were conducted using Graphite Furnace Atomic Absorption Spectrometer (GFAAS) and As detection was performed with Hydride Generation Atomic Absorption Spectrometer (HGAAS).TM samples were collected from three states of Malaysia namely Pahang, Terengganu and Kelantan. Total of sixty TM samples from various dosage forms such as capsule (50%), pill (25%), powder (21.6%) and tablet (3.4%) were analysed to determine the content of heavy metal using AAS. Three different acid digestion methods were compared to optimize the best sample preparation technique for analyzing TM samples. They were nitric –perchloric acid digestion (Method-A) nitric acid digestion (Method-B) and hydrochloric –nitric acid (Method-C) digestion respectively. It was found that Method-C showed the highest recovery compared to the other two methods (Method-A and Method-B) and the difference was found statistically significant (p< 0.05). Method validation was performed using QC standard sample, spiked TM samples and standard reference material (SRM). It was found that the limit of detection (LOD) for As, Cd, Pb, Ni, Zn and Fe were 0.11ppb, 0.1ppb, 1.17 ppb, 2.01 ppb, 0.01 ppm and 0.09 ppm respectively. Limit of quantification (LOQ) were 1.1 ppb for As, 1ppb for Cd, 11.7 ppb for Pb, 20.1 ppb for Ni, 0.1 ppm for Zn and 0.9 ppm for Fe. The recovery percentages for QC samples were ranged from 95.12- 102.4 which reflects the accuracy of the method. While the relative standard deviation (RSD) that represents the precision of the method for QC samples were in the range of 3.23-0.2. For spiked TM samples the recovery range and the RSD range were 95- 105 and 0.11-5.0 respectively. All the validation results were within the specification limit of American Organization of Analytical Chemistry (AOAC) guideline. The accuracy of the method was further checked by the analysis of SRM. The recovery percentages of all metals were in the range of 94.5-108. Among the sixty TM samples it was found that As, Cd, Pb, Ni, Zn and Fe were present in 43%, 81%, 90%, 100%, 100% and 93% of the total samples with a concentrations range of 0.214-1.325, 0.1-1.23, 1.2-19.3, 2.01-36.3, 13.2- 391 and 103.3- 1484.7 ?g/g respectively. The results further revealed the fact that 36 % of samples contain Cd higher than the permissible limit and 10% of the samples were found having Pb above the permissible limit set by NPCB.