AOAC RI ERP E-Book - DS DF

analysed according to the RINTDF procedure. The ethanolic filtrate (for SDFS determination) was concentrated to dryness and re-dissolved in 32 mL of deionised water. A sample of this was analysed by HPLC; a) directly with no desalting and no Bio-Rad ® de-ashing pre-cartridges in place; b) a sample (5 mL) was desalted by mixing with 1.5 g of Amberlite ® FPA53 (OH − ) and 1.5 g of Ambersep ® 200 (H + ) resins over 5 min and the supernatant was analysed by HPLC with no Bio-Rad ® de- ashing pre-cartridges in place; c) Sample b) was analysed with a Bio-Rad ® de-ashing pre-cartridges in place. Desalting with resins in a polypropylene tube, as described here, removes > 95% of the salt from the sample, thus ensuring more efficient use of the expensive Bio-Rad ® de-ashing pre-cartridges. This desalting step increases the effectiveness of the de-ashing cartridges and allows up to 10-times more samples to be chromatographed before the need to regenerate or replace the de-ashing cartridges.

Figure 20172007 .xxF. Desalting of samples for HPLC. Five (5) mL of concentrated eluate mixed with 1.5 g of Amberlite ® FPA53 (OH − ) and 1.5 g of Ambersep ® 200 (H + ) resins in a polypropylene tube. AOAC Research Institute ERP Use Only

Method updated 2008--08-10 This copy printed 22 August 2017

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