scholarly journals Making and Testing Sample Control on Determination of Nitrite Content in Water and Wastewater by Using UV-Visible Spectrophotometer

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Erna Styani ◽  
Endang Sri Lestari ◽  
Ika Widiana ◽  
Muhammad Ramadhan
Keyword(s):  
Waste Water ◽  
Reference Material ◽  
Certified Reference Materials ◽  
Control Sample ◽  
Stability Control ◽  
Testing Sample ◽  
Iso Guide 35 ◽  
Uv Visible ◽  
Nitrite Content

<p>This study<strong> </strong>focused on Making and Testing sample  control as reference material on determination of nitrite content in water and waste water by using UV-Visible Spectrophotometer. Sample control has been made to replaced Certified Reference Materials (CRM) for  determination of Nitrite content in water and waste water by using UV -Visible  Spectrophotometer. Substitute materials for CRM should be homogeneous and stable, so the homogenity and stability control sample that has been made in this study  is tested by using standard referring to ISO Guide 35 , 2006. The result of   this experiments shows that    the values of F<sub>stat</sub> and F<sub>table</sub>  on homogenity test are  0.796 and 3.179 (F<sub>stat</sub> &lt;  F<sub>tabl</sub><sub>e</sub>); while the values of  t<sub>stat</sub> and table<sub>  </sub>on the stability test are 0.431 and 2.101 (t<sub>stat</sub> &lt;  table),  the mean of control sample concentration is 0,0435 mg / L. All test parameters have been qualified in accordance with ISO Guide 35 , 2006. The result of this  research shows  that the control of samples on the determination of Nitrite in water and waste water by using UV-Visible Spectrophotometer can be used as  substitute for CRM and reference material.</p>

scholarly journals Cost-effective Method of Analysis for the Determination of Cadmium, Copper, Nickel and Zinc in Cocoa Beans and Chocolates

2014 ◽  
Vol 4 (1) ◽  
pp. 193 ◽  
Author(s):  
Gideon Ramtahal ◽  
Ivan Chang Yen ◽  
Isaac Bekele ◽  
Frances Bekele ◽  
Lawrence Wilson ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Reference Materials ◽  
Certified Reference Materials ◽  
Control Sample ◽  
Cost Effective ◽  
Cocoa Beans ◽  
Copper Nickel ◽  
Flame Atomic Absorption

<p>The determination of heavy metals in cocoa beans and chocolates is of great importance, due to increasingly stringent regulations being implemented by international legislative bodies and chocolate manufacturers, to protect the health of their consumers. While various techniques exist for heavy metal analyses in cocoa, this study developed a cost-effective, accurate and precise method capable of processing up to 120 samples per batch for the determination of cadmium, copper, nickel and zinc. For sample extractions, a normal laboratory hot plate and locally fabricated high-capacity digestion blocks were used, instead of dedicated block digestion or microwave digestion systems. In addition, only concentrated nitric acid was used, instead of mixed reagents used in standardized methods, for metal extractions from samples, with a sample: extractant ratio of 0.5 g : 10 mL, digestion at 130 ºC, followed by filtration and analysis by flame atomic absorption spectrophotometry. The method was validated with Certified Reference Materials, with heavy metal recoveries generally &gt;95%. Additionally, an in-house quality control sample of ground cocoa nib analyzed together with the Certified Reference Materials was used to monitor the consistency of analyses of heavy metals in cocoa bean samples.</p>

scholarly journals The problem of improving the quality of seriously issued certified reference materials of the composition of gas mixtures

2019 ◽  
Vol 15 (3) ◽  
pp. 5-13
Author(s):  
L. A. Konopelko ◽  
A. V. Kolobova ◽  
O. V. Fatina
Keyword(s):  
Reference Material ◽  
Reference Materials ◽  
Certified Reference Materials ◽  
Metrological Traceability ◽  
Gas Mixtures ◽  
Measuring Instruments ◽  
Expanded Uncertainty ◽  
Iso Guide 35 ◽  
The Russian Federation

Currently, in the Russian Federation, the metrological traceability of certified reference materials of the composition of gas mixtures in cylinders under pressure produced by manufacturers of certified reference materials is carried out in accordance with GOST 8.578-2014. Considering that certified reference materials of the composition of gas mixtures in cylinders under pressure are used for testing to approye the type of measuring instruments, verification, calibration, and graduation of gas-analytical measuring instruments used to control explosive gases and vapors, harmful components in the atmospheric air and the air of the working area, emissions from vehicles and enterprises, to control technological processes, the quality of hydrocarbon products, etc., the issue of ensuring the quality of seriously produced certified reference materials (about 100.000 cylinders with gas mixtures per year) is important. To ensure the quality of certified reference materials of gas mixtures in cylinders under pressure, mass-produced by manufacturers of certified reference materials, we offer the following actions:– manufacturers of certified reference materials’ passing of mandatory accreditation for compliance with the requirements of GOST ISO Guide 34–2014 and GOST ISO Guide 35–2015;– manufacturers of certified reference materials’ constant participation in the proficiency testing programs through interlaboratory tests;– actualizing and refining the existing set of standards defining the requirements for the entire life cycle of a certified reference material of a gas mixture in a cylinder under pressure;– improving the method of certification of a reference material by calculating the value of the expanded uncertainty of the reference material and the introducting a new coefficient «technological reserve».

Determination of inorganic arsenic in seafood: Emphasizing the need for certified reference materials

2012 ◽  
Vol 84 (2) ◽  
pp. 191-202 ◽  
Author(s):  
Ásta Heiðrún Pétursdóttir ◽  
Helga Gunnlaugsdóttir ◽  
Hrönn Jörundsdóttir ◽  
Andrea Raab ◽  
Eva M. Krupp ◽  
...  
Keyword(s):  
Reference Material ◽  
Extraction Method ◽  
Certified Reference Materials ◽  
Hydride Generation ◽  
Inorganic Arsenic ◽  
Atomic Fluorescence Spectrometry ◽  
Proficiency Tests ◽  
Icp Ms ◽  
Inorganic As

To evaluate the accuracy and robustness of an extraction method, utilizing an -alkaline-ethanolic solution and microwave heating, the certified reference material (CRM) TORT-2 was subjected to three different instrumental methodologies: high-performance liquid chromatography (HPLC), coupled with and without post-column hydride generation; inductively coupled plasma-mass spectrometry (ICP-MS); and HPLC-hydride generation-atomic fluorescence spectrometry (HPLC-HG-AFS). The three methods gave a consistent value of inorganic arsenic (As) which is near the mean value of the reported values in the literature, which, however, range by a factor of 10. Inorganic As, defined here as all As species that do not have an As–C bond, that is, the sum of arsenite and arsenate and any thiol-bound As, was found to be less than 4 % of total As concentration in 12 samples of fish meal when subjected to this extraction method followed by HPLC-ICP-MS. To date, there is no certified value of inorganic As in a seafood-based reference material to compare to in order to validate the findings. This illustrates the difficulties in quantitative determination of inorganic As in seafood and the need for a reference material for inorganic As and proficiency tests in order to introduce legislation for a maximum level of inorganic As in seafood and feed.

Atomic absorption determination of Hg (II), Cd (II), and As (III) in natural and waste water after preliminary group preconcentration

2019 ◽  
Vol 85 (2) ◽  
pp. 12-16
Author(s):  
I. V. Saunina ◽  
E. N. Gribanov ◽  
E. R. Oskotskaya
Keyword(s):  
Waste Water ◽  
Atomic Absorption ◽  
High Sensitivity ◽  
Distribution Coefficients ◽  
Neutral Medium ◽  
Atomic Absorption Determination ◽  
Absorption Determination ◽  
Relative Standard ◽  
Preliminary Group

The sorption of Hg (II), Cd (II), and As (III) by natural aluminosilicate is studied. It is shown that the mineral absorbs those toxicants in a rather wide pH range, quantitative extraction of analytes being achieved in a neutral or close to neutral medium (pH values range within 7.0 - 8.0; 6.3 - 7.5; 7.4 - 8.5 for Hg (II), As (III), and Cd (II), respectively). The effect of the time of phase contact on the degree of extraction of elements is shown. The sorption capacity of the mineral in optimal conditions of the medium acidity (0.06 mmol/g for mercury, 0.31 mmol/g for cadmium, and 0.52 mmol/g for arsenic) is determined. The distribution coefficients attain values of aboutnX 103-nX 104. A new combined method for determination of Hg (II), Cd (II), and As (III) in natural and waste water is developed and tested. The method consists in a preliminary group sorption concentration of the analytes by aluminosilicate, desorption of the analytes from the surface of the mineral and their subsequent atomic absorption determination. The correctness of the method is verified in analysis of spiked samples. The method is easy to use and exhibits high sensitivity, reproducibility and accuracy of analyte determination. The relative standard deviation does not exceed 0.13. Economic availability and possibility of using domestic sorption materials are the important advantages of the proposed procedure which can be used in the practice of laboratories monitoring the quality and safety of environmental objects.

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