Development and characteristics of a new certified reference material for landfill cover soil analysis with extraction using dilute hydrochloric acid

2020 ◽  
Vol 12 (14) ◽  
pp. 1896-1905
Author(s):  
Masataka Nishikawa ◽  
Tomoharu Sano ◽  
Kimiyo Nagano ◽  
Miyuki Ukachi ◽  
Kaoru Onishi ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Reference Material ◽  
Hydrochloric Acid ◽  
Certified Reference Material ◽  
Dilute Hydrochloric Acid ◽  
Soil Analysis ◽  
Landfill Cover Soil ◽  
Trace Heavy Metals ◽  
Landfill Cover ◽  
Support Research

A new environmental certified reference material (CRM) has been developed by the National Institute for Environmental Studies (NIES) to support research and development studies on trace heavy metals in landfill cover soils.

Time-saving application for sequential extraction of heavy metals by optimized BCR method and lixiviation from untreated sewage sludge

2009 ◽  
Vol 57 (2) ◽  
pp. 215-230 ◽  
Author(s):  
M. Jamali ◽  
T. Kazi ◽  
M. Arain ◽  
H. Afridi ◽  
J. Baig ◽  
...  
Keyword(s):  
Waste Water ◽  
Heavy Metals ◽  
Reference Material ◽  
Sewage Sludge ◽  
Sequential Extraction ◽  
Certified Reference Material ◽  
Extraction Procedure ◽  
Domestic Waste ◽  
Bcr Sequential Extraction ◽  
Optimum Recovery

This article describes an improvement in the modified BCR three-step sequential extraction procedure employed for heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in untreated domestic waste-water sewage sludge collected from different cities in Pakistan.The BCR sequential extraction protocol requires 16 h for each step, whereas in the present work optimum recoveries of all heavy metals were attained in 10 h/step. The validity of the proposed BCR sequential extraction procedure was checked using certified reference material (BCR 483). Various parameters such as time interval (2–16 h) and sample mass (0.2–1.0 g) were studied to achieve optimum recovery of the heavy metals studied. The extracted analytes were determined by atomic absorption spectrometry. The optimum recovery of heavy metals from the certified reference material and from experimental samples was achieved at a sample mass of 0.4 g, while the time required for extraction on a mechanical shaker at 30 rpm was found to be 26–32 h. The sequence of easily available (acid-exchangeable) heavy metals was determined as Cd<Zn<Ni<Cr<Pb<Cu. With the exception of Cd the dominant fractions of the heavy metals were associated with organic matter, while 31.0 and 47.8% of Cd was present in acid-soluble and reducible forms, respectively. A lixiviation test (DIN 38414-S4) was used to evaluate the leaching of heavy metals from the domestic waste-water sewage sludge used for agricultural purposes.

Kinetics of cyclization of S-ethoxycarbonylmethylisothiouronium chloride to 2-imino-4-thiazolidone

1979 ◽  
Vol 44 (3) ◽  
pp. 912-917 ◽  
Author(s):  
Vladimír Macháček ◽  
Said A. El-bahai ◽  
Vojeslav Štěrba
Keyword(s):  
Hydrochloric Acid ◽  
Dilute Hydrochloric Acid ◽  
Base Catalysis ◽  
General Base ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Kinetics Of Formation ◽  
Acid Catalyzed ◽  
Rate Limiting ◽  
Kinetics Of

Kinetics of formation of 2-imino-4-thiazolidone from S-ethoxycarbonylmethylisothiouronium chloride has been studied in aqueous buffers and dilute hydrochloric acid. The reaction is subject to general base catalysis, the β value being 0.65. Its rate limiting step consists in acid-catalyzed splitting off of ethoxide ion from dipolar tetrahedral intermediate. At pH < 2 formation of this intermediate becomes rate-limiting; rate constant of its formation is 2 . 104 s-1.

Synthesis of the semi-rigid analogues of prothiadene and dithiadene as potential antidepressant and antihistamine agents: 11-[2-(Dimethylaminomethyl)cyclohexylidene]-6,11-dihydrodibenzo[b,e]thiepins and 4-[2-(dimethylaminomethyl)cyclohexylidene]-4,9-dihydrothieno-[2,3-c]-2-benzothiepins

1985 ◽  
Vol 50 (5) ◽  
pp. 1078-1088 ◽  
Author(s):  
Zdeněk Polívka ◽  
Jiří Holubek ◽  
Emil Svátek ◽  
Jan Metyš ◽  
Miroslav Protiva
Keyword(s):  
Hydrochloric Acid ◽  
Ir Spectrum ◽  
Title Compound ◽  
Dilute Hydrochloric Acid ◽  
Amino Alcohols ◽  
Geometric Isomers ◽  
Pharmacological Testing

Reaction of dibenzo[b,e]thiepin-11(6H)-one with 2-(dimethylaminomethyl)cyclohexylmagnesium chloride gave a mixture of stereoisomeric amino alcohols IX from which four homogeneous bases (IXa to IXd) were separated by chromatography. Dehydration of these compounds with boiling dilute hydrochloric acid afforded mixtures of racemic geometric isomers of the title compound VII, which were separated by crystallization. To the prevailing less polar base VIIa (E)-configuration was assigned on the basis of the IR spectrum. Using a similar procedure, thieno[2,3-c]-2-benzothiepin-4(9H)-one gave mixture of amino alcohols X from which three homogeneous stereoisomers X-A to X-C were isolated. Their dehydration resulted in both expected racemic geometric isomers VIII-A and VIII-B. Pharmacological testing proved the character of an antidepressant for the semi-rigid analogue of dithiadene VIII.

An alternative method for assaying cerebrospinal fluid protein in the presence of methotrexate.

1988 ◽  
Vol 34 (10) ◽  
pp. 2091-2092 ◽  
Author(s):  
L M Kasper ◽  
W R Moorehead ◽  
T O Oei ◽  
M Markanich
Keyword(s):  
Cerebrospinal Fluid ◽  
Hydrochloric Acid ◽  
Trichloroacetic Acid ◽  
Dilute Hydrochloric Acid ◽  
Constant Amount ◽  
Manual Method ◽  
Turbidimetric Method ◽  
Methotrexate Concentration ◽  
Cerebrospinal Fluid Protein ◽  
Positive Interference

Abstract Therapeutic concentrations of methotrexate can cause significant positive interference in cerebrospinal fluid (CSF) protein values when assayed in the Du Pont aca. Conversely, our modified turbidimetric method, in which trichloroacetic acid (TCA) plus a sample blank containing dilute hydrochloric acid is used in place of TCA, exhibits little or no interference from methotrexate. This was verified by assaying solutions that contained a constant amount of protein (approximately 430 mg/L) and various amounts of methotrexate (0.0-2.3 x 10(-4) mol/L) by both the Du Pont aca and the manual turbidimetric method. As expected, the aca results showed increasing protein values with increasing methotrexate, whereas the manual method gave results approximating the expected protein value irrespective of the methotrexate concentration.

Sign in / Sign up

Export Citation Format

Share Document