The solid-phase extraction step was eliminated (as will be shown below), so there is the potential for nonvolatile buffer salts that are extracted into ethyl acetate to build up in the mass spectrometer source and also to suppress the electrospray ionization process (although most of the salts will remain in the aqueous phase).

Therefore, measurements in the presence of buffer salts containing Amide bonds, such as urea, can potentially affect the accuracy of the results.

At transition point, the phytase activity at the same pH was determined and compared, which could be different due to the effect of the buffer salts. It was shown that KV1 phytase worked best at pH 5.5 (Figure 4a).

The materials used in the experiment include; Streptococcus equisimilis group C, strain H46A (ATCC 12449, USA), Todd Hewitt Broth media (THB, HiMEDIA Laboratories), Trypticase Soy Agar (TSA, BBL, USA), Lysine monohydrochloride (Sigma Chemical, USA), Hexyl resorcinol (Merck, Germany), [rho]-nitro phenyl guanidinobenzoate (NPGB, Sigma Chemical, USA), 3-amino-n-caproic acid (EACA, Sigma Chemical, USA), Cyanogen bromide activated Sepharose 4B (Sigma Chemical, USA), Chromogenic substrate S-2251 (Chromogenix laboratories, Italy), Buffer salts, acids and bases (Merck, Germany).

Researchers added buffer salts to whey peptides to prepare media that were tested for their ability to inhibit culture agglutination.

The assay kit contained ATP Standard (2.0 [micro]mol ATP), ATP Assay Mix Dilution Buffer (Mg[SO.sub.4], DTT, EDTA, bovine serum albumin, tricine buffer salts), and ATP Assay Mix (luciferase, luciferin, Mg[SO.sub.4], DTT, EDTA, bovine serum albumin, tricine buffer salts).

Although ESI-MS/MS provides for very selective detection of IDS-P and IDS-IS in the presence of a large number of other metabolites present in the DBSs, it is still necessary to remove the buffer salts before ESI-MS/MS because they are present in relatively high concentration and could cause interference during the ionization process.