Document VJLEXwbbwpZ7oM4Br5ae0aRD4

Solvay Solexis S.p.A SPINETTA MARENGO (AL) - ITALY Method of Analysis PF30/83 Determination of the using Ion Chromatography (IC) Product: Category: Finished Product Edition: 2 Written by: Approved by: Date: 14/06/2006 Verified by: Pages: 6 Tables: 1 Figures: 1 1. PURPOSE AND APPLICATION FIELD Quantitative determination of the content of . PF30/83 Edition 2 14/06/06 in samples of . Page 1 of 6 2. PRINCIPLE Salification of a sample of using NaOH and solubilisation in water. Determination of the fluoride ion (F-) using ion chromatography (IC). 3. MATERIALS 3.1. Reagents 3.1.1. Standard solution of Fluorides 1000 g/ml DIONEX type or equivalent. 3.1.2. 50% NaOH - J.T. Baker or reagent of similar purity. 3.1.3. 10% NaOH: in a 50 ml volumetric flask place 10 ml of NaOH accurately measured, and dilute to volume with milliQ water. 3.1.4. MilliQ H2O 3.1.2, 3.2. Instruments and equipment 3.2.1. 3.2.2. 3.2.3. 3.2.4. 3.2.5. 3.2.6. Dionex ICS2000 Ion Chromatograph or equivalent, equipped with conductometric cell and eluant generator + CR-TC Dionex IONPAC AS14A 4mm guard column Dionex IONPAC AS14A 4mm analytical column Dionex ASRS-ULTRA 4mm Autosuppressor (External Water Mode) pHmeter equipped with combined glass electrode 50 ml and 100 ml volumetric flasks 4. SAMPLES The samples to be analysed are . CAUTION: Handle with care! (See point 7) 5. METHOD 5.1. Flow Diagram Salification using NaOH Dilution IC analysis PF 30/83 Edition 2 14/06/06 Page 2 of 6 5.2. Preparation of the standards and the sample 5.2.1. Preparation of the standards Solutions of F- at 0.3 - 0.5 - 1.0 - 3.0 mg / l In four 100 ml volumetric flasks, using a precision pipet take 30, 50, 100, 300 l respectively of the solution 3.1.1 and dilute to volume with milliQ H2O. 5.2.2. Preparation of the sample a) In a 100 ml beaker weigh 1 g of sample to a precision of 0.01 g b) Add 50 ml of MilliQ H2O and neutralise the solution very slowly with NaOH solution (3.1.3.) using the pHmeter until it is stable at pH 12. c) Pour quantitatively into a 100 ml volumetric flask and dilute to volume with MilliQ H2O. d) Homogenise. 5.3. Operating conditions and IC analysis - Loop: 50 L - Flow: 1.20 ml/min - Current suppressor: 50 mA - Eluant : 5.00 mM KOH generated using eluant generator - CR-TC : On - Retention time of F-: 9 min (NB. Aging of the column leads to progressive reduction of retention times, which must be verified when calibration is carried out). - Reading in area of peak - Pump conditions: isocratic 5.3.1. Plotting the Calibration Curve Set the operating conditions, allow the system to stabilise, verify that the conductivity is stable and inject the standards prepared in point 5.2.1 in sequence. Plot the line of calibration, recording the peak areas for each of the concentrations of the standards. PF 30/83 Edition 2 14/06/06 Page 3 of 6 5.3.2. Analysis of the samples Inject the sample solution prepared in point 5.2.2. and, using the line of calibration, calculate the concentrations of fluorides in solution. The injection is carried out immediately after the preparation. 5.4. Precision and accuracy (QA/QC) The statistical elaboration of the data obtained from six consecutive repetitions carried out on the four standards used to establish the calibration curve is shown below (Tab.1): where: ST. DEV. = standard deviation ((xii-MEAN)2/(n-1))0.5 r = laboratory repeatability (2.8 * s) (r) = % repeatability, (r / MEAN)*100 n = number of measurements precision = ( ( (max xi min xi) / 2 ) / MEAN ) * 100 PF 30/83 Edition 2 14/06/06 Page 4 of 6 In Fig. 1 the verification of the linearity of the response of the instrument (integrated area) is shown in relation to the concentration of the standards (calibration line for fluorides, where: y = A (S*min) ; x = C (mg/l) ) Figure 1 6. CALCULATIONS The concentration of calculated as follows: in the sample being examined, expressed in ppm (w/w), is where: A = in solution (g/ml) p = weight of the sample in g 7. SAFETY AND PRECAUTIONS In handling the reagents used in the present method, refer to the relative safety data sheet which must be at the disposal of those using these substances: Fluoride Standard (1000 mg/L) NaOH EGC KOH EluGen cartridge (generation of KOH 5.00 mM using eluant generator) PF 30/83 Edition 2 14/06/06 Page 5 of 6 The samples of . Handle under properly functioning aspiration hood. Handle with care wearing protective gloves for acids and protective eyewear and using all other individual protective measures obligatory in the work area. Sodium Hydroxide, which is dangerous due to its function as a base, is corrosive for mucous membranes, eyes and skin. 8. REFERENCES Reference Library : Manuals, Technical Documents, Applications, Product Literature DIONEX - P/N 053891-24 PF 30/83 Edition 2 14/06/06 Page 6 of 6