The present manuscript describes an innovative handheld device for the rapid detection of barium (Ba²⁺) in Gunshot Residue (GSR) based on the use of gold nanomaterials capped with sodium malonate. The method depends on a shift in the Light Scattering Plasmon Resonance (LSPR) peak of malonate capped gold nanoparticles (AuNPs) from 526 nm to 610.5 nm, due to the carboxylate ion aggregation between the metal and the nanoparticles leading to a change in the color. Qualitative detection was realized by the change in the color, while for quantitative analysis a handheld device has been fabricated in-house. The results were then correlated with those of standard known methods such as UV-Vis Spectroscopy and Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). The results showed better correlation between the fabricated device and standard methods with R² = 0.98. It shows a linearity range from 0.01 mg mL⁻¹ to 5 mg mL⁻¹ with a Limit of Detection (LOD) of 0.2 mg mL⁻¹. Furthermore, GSR samples were collected from cloth piece set at different range of shooting (i.e. 1 ft to 16.40 ft) using different ammunition to detect the presence of Ba²⁺ with the help of the developed device and results were found similar to those of the known methods. The hand-held device was found to be unaffected by other interfering agents (i.e. Pb²⁺, Sb³⁺, Ca²⁺, Cu²⁺, Hg²⁺, Mg²⁺, As³⁺, Cr³⁺, etc.). The results demonstrated here shows high selectivity, sensitivity and rapid method for Ba²⁺ detection in GSR, showing its greater potentiality in future.

中文翻译：

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一种使用手持设备检测枪击残留物中钡的新方法：法医应用

本手稿描述了一种用于快速检测钡 (Ba ²⁺) 在枪弹残留物 (GSR) 中，基于使用丙二酸钠封端的金纳米材料。该方法取决于丙二酸封端的金纳米粒子 (AuNP) 的光散射等离子体共振 (LSPR) 峰从 526 nm 到 610.5 nm 的偏移，这是由于金属和纳米粒子之间的羧酸根离子聚集导致颜色发生变化. 定性检测是通过颜色的变化来实现的，而对于定量分析，内部制造了一个手持设备。然后将结果与标准已知方法的结果相关联，例如紫外-可见光谱法和电感耦合等离子体发射光谱法 (ICP-OES)。结果表明，制造的设备和标准方法之间的相关性更好，R ²= 0.98。它显示了从 0.01 mg mL ^-1到 5 mg mL ^-1的线性范围，检测限 (LOD) 为 0.2 mg mL ^-1。此外，使用不同的弹药从设置在不同射击范围（即1 英尺至 16.40 英尺）的布块中收集 GSR 样本，以在开发的设备的帮助下检测 Ba ²⁺的存在，结果与已知的方法。发现手持设备不受其他干扰剂的影响（即Pb ²⁺、Sb ³⁺、Ca ²⁺、Cu ²⁺、Hg ²⁺、Mg ²⁺、As ³⁺，铬³⁺，等等）。这里展示的结果显示了 GSR 中Ba ²⁺检测的高选择性、灵敏度和快速方法，显示了它在未来的更大潜力。