LIBS for the detection of lead in ready to use henna paste and nutrients in fresh henna leaves and cultivated soils

• Published in: Talanta (Oxford) 2019-07, Vol.199, p.203-211
• Main Authors: Rehan, I., Gondal, M.A., Rehan, K., Sultana, S., Dastageer, M.A., Al-Adel, F.F.
• Format: Article
• Language: English
• Subjects: Atomic absorption spectroscopy; Detection of toxic lead; Henna analysis; Laser induced breakdown spectroscopy; Lasers; Lawsonia Plant - chemistry; Lead - analysis; Nutrients - chemistry; Plant Leaves - chemistry; Soil - chemistry; Spectrum Analysis
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2019.02.047

Commercially available ready to use henna paste, procured from the local market in Pakistan were tested to find the level of hazardous element, lead present in the samples, using Laser Induced Breakdown Spectroscopy (LIBS). The source of lead in the ready to use henna is from the artificial chemical additives in henna paste, added to enhance the color and also to speed up the dying of the henna tattoo in hand, feet, and body. Henna tattooing is an inevitable practice in the social events in the cultures of the Indian subcontinent and the Arabian Peninsula. The frequent reckless use of henna, particularly lavishly administering it to the children is quite dangerous, although the level of lead found in the commercially available ready to use henna samples are within the permissible safe level. For the sensitive detection and quantification of lead, various experimental and plasma parameters in the LIBS detection system were optimized and the system was calibrated. The quantitative analysis of lead, carried out in five different samples of ready to use henna, using LIBS revealed that the concentration of lead in these samples is between 5.5 ± 0.2 mg Kg−1 and 16.0 ± 0.2 mg Kg−1. Moreover, LIBS elemental analysis of natural henna leaves, cultivated in Sindh and Punjab regions of Pakistan, and also the soils taken from the locations of cultivation were carried out and a correlation in the elemental compositions between the henna leaves and the cultivated soil in the proximity were studied. The quantitative analysis of LIBS results were validated by atomic absorption spectroscopy (AAS) and inductively coupled plasma-optical emission spectroscopy (ICP-OES). [Display omitted] •Henna is used for tattooing and has become inevitable part of the cultures.•Processed henna paste contains hazardous level of lead for fast dying and bright color.•High level of lead ingestion due to regular use develops neurological impedance in children.•LIBS system to quantify the amount of lead present in the commercial henna paste samples was applied.