scholarly journals Speciation of Arsenic in Ground Water Samples by Ion Exchange Chromatography with Improved Sample Preparation Technique

2018 ◽  
Vol 56 (9) ◽  
pp. 853-857
Author(s):  
Thyagarajan Shanmugam ◽  
Joseph Selvaraj ◽  
Surendiran A
2019 ◽  
Vol 57 (10) ◽  
pp. 939-943
Author(s):  
Thyagarajan Shanmugam ◽  
Joseph Selvaraj ◽  
Uvaraj Mani

Abstract Chromium exists in its two stable oxidation states including trivalent chromium (Cr (III)) and hexavalent chromium (Cr (VI)) in natural waters. Chromium is an essential micronutrient in the trivalent form; however, the hexavalent form of chromium is considered to be a carcinogen. It is important to determine the chromium content along with speciation. There are a number of methods available for chromium determination. Speciation of chromium is essential to know the exact composition of chromium. Ion exchange chromatography is one of the techniques used to determine Cr (VI). The proposed method can be used to perform the speciation of Cr (III) and Cr (VI). It is a two-step process: first Cr (VI) is determined, followed by total chromium determination by treating the sample with potassium permanganate solution to oxidize the Cr (III) present in the sample to Cr (VI) and determining it as Cr (VI). Conductivity detector is used for the detection. Addition of potassium permanganate solution to the ground water samples for oxidizing the Cr (III) to Cr (VI) is the newly adopted sample preparation technique. The effect of potassium permanganate oxidation is studied in detail in the proposed method. This method can be used for chromium speciation in river water and ground water samples.


Author(s):  
Jayesh Bellare

Seeing is believing, but only after the sample preparation technique has received a systematic study and a full record is made of the treatment the sample gets.For microstructured liquids and suspensions, fast-freeze thermal fixation and cold-stage microscopy is perhaps the least artifact-laden technique. In the double-film specimen preparation technique, a layer of liquid sample is trapped between 100- and 400-mesh polymer (polyimide, PI) coated grids. Blotting against filter paper drains excess liquid and provides a thin specimen, which is fast-frozen by plunging into liquid nitrogen. This frozen sandwich (Fig. 1) is mounted in a cooling holder and viewed in TEM.Though extremely promising for visualization of liquid microstructures, this double-film technique suffers from a) ireproducibility and nonuniformity of sample thickness, b) low yield of imageable grid squares and c) nonuniform spatial distribution of particulates, which results in fewer being imaged.


1973 ◽  
Vol 30 (02) ◽  
pp. 414-424 ◽  
Author(s):  
Ulla Hedner

SummaryA procedure is described for partial purification of an inhibitor of the activation of plasminogen by urokinase and streptokinase. The method involves specific adsorption of contammants, ion-exchange chromatography on DEAE-Sephadex, gel filtration on Sephadex G-200 and preparative electrophoresis. The inhibitor fraction contained no antiplasmin, no plasminogen, no α1-antitrypsin, no antithrombin-III and was shown not to be α2 M or inter-α-inhibitor. It contained traces of prothrombin and cerulo-plasmin. An antiserum against the inhibitor fraction capable of neutralising the inhibitor in serum was raised in rabbits.


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