AOAC SPIFAN Nutrients ERP Review (March 14, 2019)

Fluor-03 (Feb. 2019) FOR ERP USE ONLY DO NOT DISTRIBUTE

A. Apparatus (a) Analytical balance .—Minimum weighing capacity of at least 0.0001 g. (b) Stir plate. (c) Vortex mixer.

(d) System ion chromatography (IC 940.1500 Professional IC with MagIC Net 3.2 software package).— Corrosion-resistant components including an autosampler (858.0020 Professional Sample Processor), dialysis cell (6.2729.100) for inline dialysis with a 0.2 µm membrane (Dialysis membrane filters, pore size 0.2 µm, diameter 47 mm, cellulose acetate, 6.2714.010), dosino (3; 2.800.0010) for suppressor regeneration, inline liquid sample handling, and dose-in gradient, 6- port switching valve, peristaltic pump (2 lines) for sample transfer from autosampler to dialysis cell and from dialysis cell to the injector, high-pressure pump (1), MSM and MCS suppressor for sequential suppression, thermostat/column oven to set column temperature, and a conductivity detector. Autosampler should be capable to handle 50 mL vials. Furthermore, a PEEK sample loop (6.1825.210) is necessary for injection of 20 μL sample (see chromatographic conditions). (e) Columns.— Metrosep A Supp 16 - 250/4.0 (4.6 um, 250 x 4.0 mm, 6.1031.430), Metrosep RP2 Guard/3.5 (6.1011.030), Metrosep A Trap 1 – 100/4.0 (6.1014.00) or equivalent (www.metrohm.com) B. Materials (a) Sample tubes .—50 mL PP screw cap tube, 114 x 28 mm, conical base, Sarstedt (62.548.004) or equivalent. (b) Al foil .—Circular aluminum foil sheets of 80 mm diameter (thickness: 0.010 mm) to cover PP tubes for analysis (6.2820.000). (c) Volumetric flasks .—Assorted sizes. (d) Pipettes .—Adjustable-volume pipettes with disposable tips (10-1000 µL). (e) Disposable pipettes . (f) Glas bottles . —Assorted sizes, i.e. for carbonate eluent (2 L), concentrate for dose-in gradient (2 L), UPW for liquid handling and sample transfer (2×2 L), suppressor reagent solution (1 L), MeOH for rinsing (100 mL, opaque) C. Reagents (a) Sodium carbonate .—Sodium carbonate (Na 2 CO 3 ), anhydrous, for analysis, EMSURE®, ACS, Merck (1.06393.1000). (b) Sodium Hydroxide. —Sodium Hydroxide (NaOH), 30%, suprapure®, Merck (1.05589.0250). (c) Sulfuric acid. —Sulfuric acid solution (H 2 SO 4 ), 0.5 M, Fluka (35354-1L). (d) Methanol. —Methanol (MeOH), Emsure® ACS, for analysis, Merck (1.06009.2511) (e) Fluoride CRM . —Fluoride (F - ) Standard for IC, certified reference material (CRM), 1000 ± 4 mg/L F - , TraceCERT®, Sigma-Aldrich (77365-100ML) (f) Chloride CRM . —Chloride (Cl - ) Standard for IC, certified reference material (CRM), 1000 ± 4 mg/L Cl - , TraceCERT®, Sigma-Aldrich (39883-100ML) (g) Acetate CRM . —Acetate (CH 3 COO - ) Standard for IC, certified reference material (CRM), 1000 ± 4 mg/L CH 3 COO - , TraceCERT®, Sigma-Aldrich (51791-100ML) (h) Formate CRM . —Formate (COO - ) Standard for IC, certified reference material (CRM), 1000 ± 5 mg/L COO - , TraceCERT®, Sigma-Aldrich (44293-100ML) (i) Lactate CRM . —Lactate (C 3 H 5 O 3 - ) Standard for IC, certified reference material (CRM), 1001 ± 5 mg/L C 3 H 5 O 3 - , TraceCERT®, Sigma-Aldrich (07096-100ML) (j) Ultrapure water (UPW).— Laboratory water, ≥15 MΩ∙cm. (k) SRM 1849a. — Standard Reference Material ® 1849a, Infant/Adult Nutritional Formula, National Institute of Standards and Technology D. Preparation of mobile phase, suppressor regenerant and rinsing solutions for ion chromatography (a) Mobile phase A - carbonate eluent (1.875 mM Na2CO3 and 0.1875 mM NaOH, 2000 mL.).— Dilute 397 mg sodium carbonate salt (C.a) and 37.5 µL sodium hydroxide (C.b) to 2000 mL UPW (C.f) and mix well on a stir plate.

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