Radiometric analysis of rock and soil samples of Leepa Valley; Azad Kashmir, Pakistan

In this article, we present results obtained from a radiometric survey that was conducted in the Leepa Valley of Azad Jammu & Kashmir, Pakistan. The purpose of current study is to appraise the radioactivity levels and the associated health hazards due to the terrestrial radionuclide in soil and rock samples. In this regard, 16 soil and 17 rock samples were collected from different locations of the Leepa Valley. After processing the samples, activity concentrations of primordial (²³²Th, ²²⁶Ra and ⁴⁰K) and anthropogenic (¹³⁷Cs) radionuclides were determined using a P-type coaxial high purity germanium detector. From the results obtained the mean activity concentrations of radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K in the soil samples were found to be 31.25 ± 0.46, 44.1 ± 1.07 and 575 ± 8.89 Bq kg^?1 respectively. Whilst, in rock samples ²²⁶Ra, ²³²Th and ⁴⁰K mean activities were found as 28.46 ± 0.45, 48.63 ± 1.12 and 666.7 ± 9.39 Bq kg^?1, respectively. The ¹³⁷Cs concentration level in soil and rock samples is found to be 15.04 ± 0.29 and 5.7 ± 0.16 Bq kg^?1, respectively. The average radium equivalent activity (R _aeq) was found as 143.16 and 142.93 Bq kg^?1 in soil and rock samples, respectively. These findings are less than the recommended safe value of 370 Bq kg^?1 as given in OECD report (1979). The values of external (H _ex) and internal hazard index (H _in) are also less than unity. Mean value of absorbed dose rate was found as 69.78 nGy h^?1 for the soil samples, which is in good agreement with the world wide average value (70 nGy h^?1). Mean value of absorbed dose rate from rock samples was found as 70.01 nGy h^?1. Mean values of the annual effective dose is also lower than the values reported for different other countries of the world.     

Vitamin C derivatives as new coreactants for tris(2,2'-bipyridine)ruthenium(II) electrochemiluminescence

Vitamin C derivatives (VCDs) have been widely used as the alternative and stable sources of vitamin C, and accordingly exhibit many new applications, such as anti-tumor and central nervous system drug delivery. In this study, their Ru(bpy)₃²⁺ electrochemiluminescence (ECL) properties have been investigated for the first time using well-known ascorbyl phosphate and ascorbyl palmitate as representative VCDs. Ascorbyl phosphate and ascorbyl palmitate are VCDs with different substituted positions. Both of them increase Ru(bpy)₃²⁺ ECL, indicating that other VCDs may also enhance Ru(bpy)₃²⁺ ECL signal. The calibration plot for ascorbyl phosphate is linear from 3 × 10⁻⁶ to 1.0 × 10⁻³ M with a detection limit of 1.4 × 10⁻⁶ M at a signal-to-noise ratio of 3. The relative standard deviation is 3.6% for six replicate measurements of 0.01 mM ascorbyl 2-phosphate solution. The proposed method is about one order of magnitude more sensitive than electrochemical and UV–vis methods for the determination of ascorbyl phosphate, and is used successfully for the determination of ascorbyl phosphate in whitening and moisturising body wash.