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PO-CON1794E Quantitative determination of heavy metals in ayurvedic tablets using ICP-MS ASMS 2017 WP 110 Ankush Bhone 1 , Sampada Khopkar 1 , Mangesh Pawar 1 , Amol Shinde 1 , Ajit Datar 1 , Jitendra Kelkar 1 , Pratap Rasam 1 Shimadzu Analytical (India) Pvt. Ltd., 1 A/B Rushabh Chambers, Makwana Road, Marol, Andheri (E), Mumbai-400059, Maharashtra, India.
2 Quantitative determination of heavy metals in ayurvedic tablets using ICP-MS Introduction Ayurvedic medicine originated in India more than 2000 years ago and relies heavily on ayurvedic products. Approximately 80% of Indian population makes use of Ayurveda through more than one-half million Ayurvedic practitioners working in Ayurvedic hospitals and clinics. Heavy metals are considered as possible human carcinogen by the World Health Organization's International Agency if it exceeds the permissible limit. Some ayurvedic products do contain toxic materials such as heavy metals, pesticides, etc. Exposure to heavy metals such as Arsenic (As), Cadmium (Cd), Lead (Pb), and Mercury (Hg) can cause adverse health effects and toxicity. The objective of this study is to develop a sensitive, selective, accurate and reliable method using Shimadzu ICPMS-2030 to determine the heavy metals from ayurvedic tablets. Methods and Materials Commercially available ayurvedic tablets (Figure 1) were used for the extraction study of heavy metals. The samples were digested using Anton Paar microwave digestion system. as per the programme Table 1. Pre-spiked recoveries were established by spiking samples with standard solution of heavy metals followed by subsequent analysis. Figure 1 Ayurvedic plant resources and tablets Sample pretreatment procedure by microwave digestion Microwave digestion: Transfer 0.1g tablet powder in microwave digester PTFE vessel Add 6mL nitric acid, 2mL hydrogen peroxide, 0.1mL hydrofluoric acid, 0.25mL of hydrochloric acid Sample digestion in microwave digester as per programme & volume make up to 50mL
3 Figure 2 Shimadzu ICPMS-2030 Inductively coupled plasma mass spectrometer Quantitative determination of heavy metals in ayurvedic tablets using ICP-MS Sample preparation is very crucial and important step in elemental analysis. ayurvedic drugs contain both high amount of organic and inorganic components which are very difficult to break. A robust sample preparation method was developed by using combination of acids to digest the sample completely. Pre-spiked std. recovery study was performed to check the extraction method and matrix interference. Quantification of heavy metals (As, Cd, Pb and Hg) was performed using internal standard method by plotting calibration curves for respective elements. Best elemental masses were selected for analysis based on their isotopic ratio, background equivalent concentration (BEC) values and isobaric interference. The internal standard was selected for elements according to the best possible match in terms of proximity with respect to mass to charge ratio and ionization behavior. It was added to standards and samples at a concentration of 1μg/L in final volume. ICPMS LabSolutions software special features like “qualitative analysis and development assistant” were used for auto method optimization. Also “quantitative analysis and diagnosis Assistant” were used for auto corrected report generation. Method development Results 1 2 3 4 10 10 10 10 Steps Ramp (min) 100 150 180 200 Temp (°C) 05 10 10 10 Hold time (min) Table 1: Microwave digester programme
4 Quantitative determination of heavy metals in ayurvedic tablets using ICP-MS Torch : Mini torch Radiofrequency : 1.2 kW Sampling depth : 5 mm Plasma gas (L/min) : 8.0 Auxiliary gas (L/min) : 1.1 Carrier gas (L/min) : 0.7 Cell voltage : -21 V Cell gas (mL/min) : 6.0 Energy Filter : 7V Chamber temp. : 5 ˚C Number of scans : 10 Integration time : 2sec Peristaltic pump speed : 60 r.p.m.- High 20 r.p.m.- Low Isotopes monitored = 75 As, 111 Cd, 208 Pb, 202 Hg Internal standard = 89 Y Analytical Conditions (ICPMS-2030) Figure 3 shows standard calibration linearity curves in the concentration range of 0.5μg/L to 50μg/L. Results of regression analysis on calibration curves were shown in Table 2. Figure 3 Standard calibration linearity curves 0.5μg/L to 50μg/L 0 25 50 Concentration (ug/L) 0 5 10 15 20 25 Intensity As 75 (DBN) 0 25 50 Concentration (ug/L) 0 5 10 15 20 25 Intensity Cd 111 (DBN) 0 25 50 Concentration (ug/L) 0 50 100 150 Intensity Pb 208 (DBN) 0 25 50 Concentration (ug/L) 0 5 10 15 20 25 30 Intensity Hg 202 (DBN)
5 Quantitative determination of heavy metals in ayurvedic tablets using ICP-MS As Cd Pb Hg 0.99999 0.99990 0.99983 0.99995 Elements Correlation coefficient (r) 0.2254 0.0009 0.0368 0.0099 LOD (3s) (μg/L) 0.7515 0.0029 0.1227 0.0333 LOQ (10s) (μg/L) Table 2 Results of regression analysis on calibration curves by ICPMS The quantitative analysis of As, Cd, Pb, Hg elements from ayurvedic tablets was performed by ICPMS-2030 and results obtained are shown in Table 3. Recovery study was done by spiking respective sample with standard elements and analyzing the same under similar analytical conditions. The results obtained were evaluated for statistical parameters like accuracy and linearity. Accuracy in terms of recovery was found to be between 80% to 120% for pre-spiked samples at level of 1μg/L & 5μg/L and %RSD obtained for all standards and samples were less than 6 as shown in Table 4. Linearity with co-relation coefficient greater than 0.999 was achieved. Quantitative Results 92.67 91.37 - 92.87 %Recovery (Accuracy) 98.63 87.00 83.00 85.97 %Recovery (Accuracy) 5μg/L 1μg/L %RSD 5.07 2.38 3.73 2.93 %RSD 3.02 2.79 - 3.68 Table 4 Average accuracy at 1.0μg/L & 5.0μg/L in ayurvedic tablets (n = 6 replicates) As Cd Pb Hg Elements 89.06 5.00 115.75 6.20 Ayurvedic tablet (μg/L) %RSD 4.89 3.76 4.84 2.34 Table 3 Average elemental results of ayurvedic tablets (n = 6 replicates) As Cd Pb Hg Elements
First Edition: December, 2017 © Shimadzu Corporation, 2017 Quantitative determination of heavy metals in ayurvedic tablets using ICP-MS Conclusions Heavy metals in ayurvedic tablets at ppb level were quantitatively estimated using ICPMS. The proposed ICP-MS method has been proved to be a accurate and sensitive for detection of heavy metals in ayurvedic products. A new “development assistant” function of LabSolutions software helped in setting analysis method (like linearity level, internal standard). Disclaimer: Shimadzu ICPMS-2030 and application in this poster are intended for Research Use Only (RUO). Not for use in diagnostic procedures. Not available in the USA, Canada and China.