环境科学基础实验一油

1、油的测定预习时，洗净玻璃器皿（每个小组1支100 mL量筒，1支10 mL量筒，2个分液漏斗，1支5或10 mL移液管，7支25 mL比色管，1个普通小漏斗），一定要用洗洁剂洗净，以免结果偏高。在架子上控干。检查分液漏斗，不得涂抹凡士林。预 习 安 排Purpose: To understand the principle of petroleum determination. To master one of the sample pretreatment methods, liquid-liquid extraction. To get familiar with the operatio

2、n of UV and fluorescence spectrometers. 2.10 Determination of Petroleum ExtractionOne of the separation methodsLiquid-liquid (L-L) extraction, liquid phaseSolid phase extraction (SPE)Solid phase micro extraction (SPME)Liquid phase micro extraction (LPME)Detection MethodsUV method:All the compounds a

3、bsorbing 220-225 nm lights will be counted as petroleum overestimatedFlorescence method:Only the compounds absorbing and emitting certain lights (280/345 nm) can be counted as petroleum underestimatedDetermination WavelengthUV:Alkenes (higher than 214 nm)Aromatic (about 254 nm)Choose 225 nmFluoresce

4、nce:excitation wavelength 280 nmemission wavelength 345 nmProcedure1. L-L extraction with cyclohexane: acidizing, partition, separation2. Determination with UV and fluorescence (Flu): organic phase, dry, wavelength3. Sample handling one UV calibration curve for a small group; one Flu calibration cur

5、ve for a large group; one sample for each student.(1) Put 100 mL water sample into a separatory funnel, add 2 mL 1+1 H2SO4 and 2 g NaCl.(2) Use 5 mL cyclohexane to rinse the sample container, transfer into the funnel.(3) Shake the funnel for 3min. (4) Let it settle until two obvious layers appear, c

6、ollect the aqueous phase of lower layer into another funnel. (5) collect organic solution into a 25mL volumetric tube through a regular funnel filled with Na2SO4.(6) Use 5 mL cyclohexane to rinse the first funnel, transfer into the second funnel.(7) Repeat step 3-5, combine the organic solutions.(8)

7、 Dilute the organic solution to 10 mL with cyclohexane, ready for instrumental analysis.（1）振摇水样瓶后，用量筒量取100 mL水样，倒入分液漏斗中。加入2 mL 1+1硫酸和2 g氯化钠。（2）用5 mL环己烷清洗量筒，移入分液漏斗。振荡萃取3 min，静置使之分层。将下层的水相收集至另一分液漏斗中，将环己烷相经装有无水硫酸钠的漏斗，收集至25 mL比色管中。（3）重复（2）的萃取步骤一次，但5 mL环己烷清洗分液漏斗。弃去水相，合并萃取液。（4）用环己烷将萃取液定容到10 mL。此溶液将用于紫外分光光度法和荧光法的测定。萃取步骤Additional QuestionsShould the solutions of the calibration curve be extracted as the samples? And why?Discuss the possible deviation an