Metrological Evaluation of Prepared Turbidity Working Standard Solutions to achieve Traceability for Textile Waste Water Effluents | ||||
| Egyptian Journal of Chemistry | ||||
| Article 7, Volume 60, Issue 4, August 2017, Page 563-575 PDF (637.01 K) | ||||
| DOI: 10.21608/ejchem.2017.938.1046 | ||||
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| Authors | ||||
Saher Fawzy Ibrahim   1; Dalia Mohamed Essa2
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| 1National institute of standards | ||||
| 2National Institute for standards, Tersa st. El-haram, Giza, Egypt | ||||
| Abstract | ||||
| Working standard must be stable, thus the material should be tested for stability and homogeneity testing complying ISO standard methods with detailed description of how their features and characteristics facilitate all aspects of good laboratory practice (GLP). Stock solutions of (4000) NTU formazin turbidity suspensions were prepared, from this stock a series of diluted suspensions were prepared, and then verified by testing their pH, and spectrophotmatric absorbance values in accordance with published international models. Finally the statistical parameters and accompanied uncertainty for each certified value was calculated. The prepared stock working standard (4000 NTU) solutions were verified via applying the requirements of ISO/IEC 17034 for the homogeneity and stability testing. The results obtained verified the homogeneity and the stability of these working standards as a primary stock for about one year shelf time stability. These prepared stock solutions can be used as working standards for calibrations of turbidity meters that used for testing the turbidity of textile waste water effluents. The main goal of the study is the developing of these standards locally in Egypt. As an applied part the turbidity values of the scouring solutions from different textile fabrics -were measured, these fabrics were ; cotton, wool, silk, nylon and polyester, after calibration of the used turbiditmeter once by the purchased formazin standards and another time by the prepared working standards. Where comparable results were obtained which ensured the suitability of these prepared working standards. | ||||
| Keywords | ||||
| Formazin Working Standard; CRM; Homogeneity; stability; Statistical parameters; Turbidity; Textile effluents; fabrics; Scouring | ||||
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