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Mercury¡ªFCC iron powder Dithizone Stock Solution Dissolve 30 mg of dithizone in 1000 mL of chloroform, add 5 mL of alcohol, and mix. Store in a refrigerator in a dark bottle. Prepare fresh each month. ¶þÁòëêÖü±¸Òº ÓÃ1000mLÂÈ·ÂÈܽâ30mgË«Áòë꣬¼Ó5mL¾Æ¾«£¬»ìºÏ£¬°µÉ«Æ¿±ùÏäÖд¢´æ£¬Ã¿ÔÂÐÂÖÆ±¸¡£ Dithizone Extraction Solution On the day of use, dilute 30 mL of Dithizone Stock Solution to 100 mL with chloroform. Ë«ÁòëêÌáȡҺ ÔÚʹÓõ±Ì죬ÓÃÂÈ·ÂÏ¡ÊÍ30ml¶þÁòëêÖü±¸ÒºÖÁ100ml¡£ Hydroxylamine Hydrochloride Solution Dissolve 20 g of hydroxylamine hydrochloride in sufficient water to make about 65 mL, transfer the solution into a separator, add a few drops of thymol blue TS, and then add ammonium hydroxide until a yellow color appears. Add 10 mL of 1:25 sodium diethyldithiocarbamate solution, mix, and allow to stand for 5 min. Extract the solution with successive 10 to 15 mL portions of chloroform until a 5-mL test portion of the chloroform extract does not develop a yellow color when shaken with a dilute cupric sulfate solution. Add 2.7 N hydrochloric acid until the extracted solution is pink, adding one or two more drops of thymol blue TS, if necessary, then dilute to 100mL with water, and mix. ÑÎËáôǰ·ÈÜÒº Óóä×ãË®Èܽâ20gÑÎËáôǰ·³ÉÔ¼65mlÈÜÒº£¬×ªÒÆÈÜÒºÖÁseparator£¬Ìí¼Ó¼¸µÎ÷êÏã²Ý·ÓÀ¶£Ô£Ó£¬È»ºóÌí¼ÓÇâÑõ»¯ï§Ö±ÖÁ¸ÕÏÖ»ÆÉ«¡£Ìí¼Ó10mlµÄ1£º25¶þÒÒ»ù¶þÁò´ú°±»ù¼×ËáÄÆ£¬»ìºÏºó¾²ÖÃ5min¡£Add 10 mL of 1:25 sodium diethyldithiocarbamate solution, mix, and allow to stand for 5 min. Extract the solution with successive 10 to 15 mL portions of chloroform until a 5-mL test portion of the chloroform extract does not develop a yellow color when shaken with a dilute cupric sulfate solution.¡£Ìí¼Ó2.7 NµÄÑÎËáÖ±µ½ÌáȡҺ±ä·ÛºìÉ«£¬ÈçÐèÒª¿ÉÌí¼ÓÒ»µÎÖÁ¶àµÎ÷êÏã²Ý·ÓÀ¶£Ô£Ó£¬È»ºóÓÃˮϡÊÍÖÁ100mlºó»ìºÏ¡£ Mercury Stock Solution Transfer 33.8 mg of mercuric chloride, accurately weighed, into a 100-mL volumetric flask, dissolve in 1 N hydrochloric acid, dilute to volume with the acid, and mix. Each milliliter contains the equivalent of 250 mg of mercury. ¹¯´¢´æÒº ׼ȷ³ÆÁ¿33.8mgµÄÂÈ»¯¹¯£¬¼Óµ½100mlÈÝÁ¿Æ¿ÀÓÃ1NÑÎËáÈܽâºóÓÃËáÏ¡ÊͶ¨ÈÝ»ìºÏ¡£Ã¿mlº¬250mg Hg¡£ Diluted Standard Mercury Solution Transfer 2.0mL of Mercury Stock Solution into a 100-mL volumetric flask, dilute to volume with 1 N hydrochloric acid, and mix. Each milliliter contains the equivalent of 5 mg of mercury. Ï¡Êͱê×¼¹¯ÈÜÒº¡£2.0ml¹¯´¢´æÒº¼Óµ½100mlÈÝÁ¿Æ¿£¬ÓÃ1NÑÎËáÏ¡ÊͶ¨ÈÝ¡¢»ìºÏ¡£Ã¿mlº¬5mg¹¯¡£ Sodium Citrate Solution Dissolve 250 g of sodium citrate dihydrate in 1000mL of water. ÄûÃÊËáÄÆÈÜÒº¡£ 1000mlË®¶¨ÈÜÈܽâ250g ÄûÃÊËáÄÆ Sample Solution Transfer 1 g of sample into a 250-mL beaker, add 20mL of 1:2 nitric acid, and digest on a steam bath for about 45 min. Add 5 mL of 1:3 hydrochloric acid, and continue heating on the steam bath until the sample is dissolved. Cool to room temperature, and filter, if necessary, through a medium-porosity filter paper. Wash the paper with a few milliliters of water, add 20mL of Sodium Citrate Solution and 1mL of Hydroxylamine Hydrochloride Solution to the filtrate, and adjust the pH to 1.8 with ammonium hydroxide. ÑùÆ·ÈÜÒº 1gÑùÆ· 250ml beaker £¬Ìí¼Ó20ml 1£º2µÄÄûÃÊËᣬÕôÆûÔ¡Èܽâ45min¡£Ìí¼Ó5ml 1£º3µÄÑÎËᣬ¼ÌÐøÕôÆûÔ¡¼ÓÈÈÖ±ÖÁÑùÆ·Èܽ⡣ÀäÈ´ÖÁÊÒκó¹ýÂË£¬Èç¹ûÐèÒª£¬Í¨¹ýÖмä¶à¿×ÐÔÂËÖ½¡£Óü¸ºÁÉýˮϴÂËÖ½ºó¼ÓÈë20mlÄûÃÊËáÄÆÈÜÒººÍ1ºÁÉýÑÎËáôǰ·ÈÜÒº¹ýÂË£¬ÓÃÇâÑõ»¯ï§µ÷ÕûpHÖÁ1.8¡£ Procedure (Note: Because mercuric dithizonate is light sensitive, this procedure should be performed in subdued light.) Prepare a control by treating 1.0 mL of Diluted Standard Mercury Solution (5 mg Hg) in the same manner and with the same reagents as directed for the preparation of the Sample Solution. Transfer the control and the Sample Solution into separate 250-mL separators, and treat both solutions as follows: Extract with 5mL of Dithizone Extraction Solution, shaking the mixtures vigorously for 1 min. Drain carefully, collecting the chloroform in another separator. If the chloroform does not show a pronounced green color caused by excess reagent, add another 5mL of the extraction solution, shake again, and drain into the separator. Continue the extraction with 5-mL portions, if necessary, collecting each successive extract in the second separator, until the final chloroform layer contains dithizone in marked excess. Add 15mL of 1:3 hydrochloric acid, to the combined chloroform extracts, shake the mixture vigorously for 1 min, and discard the chloroform. Extract with 2mL of chloroform, drain carefully, and discard the chloroform. Add 1mL of 0.05M disodium EDTA and 2mL of 6 N acetic acid to the aqueous layer. Slowly add 5mL of 6 N ammonium hydroxide, and cool the separator. Transfer the solution into a 150-mL beaker, adjust the pH to 1.8 with 6 N ammonium hydroxide or 1:10 nitric acid, using a pH meter, and return the solution to the separator. Add 5.0 mL of Dithizone Extraction Solution, and shake vigorously for 1 min. Allow the layers to separate, insert a plug of cotton into the stem of the separator, and collect the dithizone extract in a test tube. Determine the absorbance of each solution in 1-cm cells at 490 nm with a suitable spectrophotometer, using chloroform as the blank. The absorbance of the Sample Solution does not exceed that of the control. ³ÌÐò£º£¨×¢£ºÒòΪmercuric dithizonateÊǹâÃô¸Ð£¬±¾³ÌÐòÊÇÔÚ°µ¹âϽøÐС££©ÓÃ1.0ºÁÉýÏ¡Ê͵ıê×¼¹¯ÈÜÒº£¨5mg ¹¯£©ÓÃÓëÑùÆ·ÈÜÒºÏàͬµÄ·½Ê½ºÍÊÔ¼ÁÅäÖöÔÕÕÈÜÒº¡£×ªÒƶÔÕÕºÍÑùÆ·ÈÜÒºÖÁ250mlµÄseparatorÖУ¬°´ÕÕÏÂÃæ·½Ê½´¦ÀíÁ½ÖÖÈÜÒº£ºÌáÈ¡5mlË«ÁòëêÌáȡҺ£¬Ò¡¶¯»ìÔÈ1min¡£Ð¡ÐÄÅÅË®£¬ÓÃÁíÒ»¸öseparatorÊÕ¼¯Âȷ¡£Èç¹ûÂÈ·ÂûÓÐÓÉÓÚ¹ýÁ¿ÊÔ¼Áµ¼ÖµÄÃ÷ÏÔµÄÂÌÉ«£¬Ìí¼ÓÁíÍâ5mlÌáȡҺ£¬ÔÙÕñµ´£¬Åŵ½separatorÖС£¼ÌÐøÓÃ5ml±ÈÁеÄÌáȡҺ£¬Èç¹ûÐèÒªµÄ»°£¬ÔÚµÚ¶þseparatorÖÐÊÕ¼¯Ã¿´Î¹ýÁ¿µÄÌáȡҺ£¬Ö±µ½×îÖÕÂȷ²ãÃ÷ÏÔ°üº¬¹ýÁ¿Ë«Áòëê¡£Ìí¼Ó15mlµÄ1£º3µÄÑÎËᣬÖÁ»ìºÏµÄÂÈ·ÂÌáÈ¡ÎïÖУ¬Õñµ´»ìºÏÒº1min£¬¶ªÆúÂȷ¡£ÓÃ2mlÂÈ·ÂÌáÈ¡£¬Ð¡ÐÄÅÅ£¬¶ªÆúÂȷ¡£Ìí¼Ó1ml0.05M Na2EDTA ºÍ2ml 6NµÄ´×ËáÖÁË®²ã¡£»ºÂýÌí¼Ó5ml 6N ÇâÑõ»¯ï§£¬ºóÀäÈ´separator¡£×ªÒÆÈÜÒºÖÁ150mlµÄbeaker£¬µ÷ÕûpHÖÁ1.8 ÓÃ6N °±Ë®»ò1£º10µÄÏõËᣬÓÃpH¼Æ£¬È»ºó·µ»ØÈÜÒºÖÁseparator¡£Ìí¼Ó5.0mlµÄË«ÁòëêÌáȡҺ£¬Ò¡¶¯1min¡£ÔÊÐí²ã·Ö¿ª£¬ÈûÉÏÒ»ÍÅÃÞ»¨Ö®separatorµÄ¾±²¿£¬ÓÃÊÔ¹ÜÊÕ¼¯Ë«ÁòëêÌáȡҺ¡£²â¶¨Ã¿¸öÈÜÒºµÄÎü¹â¶È£¬ÔÚ490nmµÄÌõ¼þÏ¡£ÓÃÂÈ·Â×ö¿Õ°×¡£ÑùÆ·ÎüÊÕÖµ²»Ó¦³¬¹ý¶ÔÕÕ¡£ [ Last edited by signal023 on 2009-3-31 at 11:31 ] |
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