Arsenic test kit in medicinal plant products

The contamination of arsenic in medicinal plant products could be either intentional for alleged medicinal or accidental purposes. Arsenic test kit was developed on the basis of Gutzeit reaction that generates arsine gas which is then captured with silver nitrate. Quantitation of arsenic was done by comparison of the color of arsenic and silver nitrate with a developed standard arsenic color tab. Limit of detection of the test kit was 0.4 ppm that is below the 4 ppm-FDA allowable legal contamination in medicinal products of Thailand. The developed test kit was validated through an inter-laboratory comparison performed in 124 samples using graphite furnace atomic absorption spectrometry as a conventional standard method. The result revealed acceptable percentage of sensitivity, specificity and accuracy that were 85.71, 86.46 and 86.29 respectively. Satisfaction of the test kit was also evaluated among the inter-laboratories. The data also showed the practical usefulness of test kit. In addition, concerning the test kit convenience, accessories and packaging 51.52% were also highly satisfied. The procedure time is only 7–10 minutes. Moreover, the kit shelf life was also evaluated. It could be kept both at room temperature and 4 ^oC for 6 and 12 months respectively. This Arsenic test kit is therefore appropriate to use for quality control by medicinal plant product manufacturers and for customer protection by responsible personnel from all public and private agencies.