Research & Development Center, Saudi Aramco, Dhahran 31311, Kingdom of Saudi Arabia.
Environ Monit Assess. 2013 May;185(5):3681-5. doi: 10.1007/s10661-012-2819-2. Epub 2012 Aug 17.
The determination of mercury in crude oil and petroleum products is particularly difficult due to the volatile nature of both mercury and the matrix, which may lead to significant loss of the analyte. A simple extraction method for total mercury has been developed to determine total mercury in crude oil using cold vapor atomic fluorescence spectrometry. The homogenized crude oil sample was diluted to 5, 10, and 20 % (w/w) in toluene. The diluted crude oil samples were spiked with 10 and 40 μg/kg (w/w). The samples were extracted using an oxidant/acid solution, BrCl/HCl. The mercury was extracted into the aqueous phase; the ionic mercury was then reduced to volatile elemental mercury (Hg(0)) by stannous chloride (SnCl2). The mercury vapor was detected by Merlin cold vapor atomic fluorescence spectrometry at a 253.7-nm wavelength. The average recoveries for mercury in spiked diluted crude oil (10 and 40 μg/kg, w/w) were between 96 and 103 %, respectively, in 5 and 10 % spiked diluted crude oil. Whereas, low recoveries (<50 %) were recorded in 20 % diluted spiked crude oil. The method detection limit was calculated as t (0.01)(n - 1) × SD where t is the student's value for 99 % confidence level and standard deviation estimate with n - 1 degrees of freedom. The method detection limit was found to be 0.38 μg/kg based on 5 g of diluted crude oil sample. The method is sensitive enough to determine low levels of mercury in crude oil.
由于汞和基质的挥发性，特别是在原油和石油产品中测定汞尤其困难，这可能导致分析物的大量损失。本文采用冷原子荧光光谱法，建立了一种简单的萃取方法，用于测定原油中的总汞。将均匀化的原油样品用甲苯稀释至 5、10 和 20%（w/w）。用 10 和 40μg/kg（w/w）向稀释后的原油样品中添加内标。用氧化剂/酸溶液（BrCl/HCl）萃取样品。汞被萃取到水相中；然后用氯化亚锡（SnCl2）将离子汞还原为挥发性元素汞（Hg(0)）。用 Merlin 冷原子荧光光谱仪在 253.7nm 波长下检测汞蒸气。在 5%和 10%添加的稀释原油中，添加的汞在添加的稀释原油（10 和 40μg/kg，w/w）中的平均回收率分别在 96%至 103%之间；而在 20%稀释添加的原油中，回收率较低（<50%）。方法检出限是按以下公式计算的：t (0.01)(n - 1) × SD，其中 t 是 99%置信水平的学生值，标准偏差是根据 n-1 个自由度估计的。基于 5g 稀释后的原油样品，方法检出限为 0.38μg/kg。该方法足够灵敏，可以测定原油中低水平的汞。
