Electrospray ionization mass spectrometric studies on the amphoteric surfactant cocamidopropylbetaine

Abstract

After liquid chromatographic (LC) separation, electrospray ionization mass spectrometry (ESI-MS) was investigated for the determination of the amphoteric surfactant cocamidopropylbetaine (CAPB). In the positive ion mode the molecule formed the adduct ions [M + H](+), [M + Na](+) and [M + K](+). Adducts of these cations were also detected with decreasing abundance as dimer and trimer clusters. Additionally, doubly charged molecular ions with different combinations of cations were identified. It was noticed that the relative abundances of individual cation adducts were not reproducible, apparently owing to varying contents of alkali metal ions originating from the solvent and the sample. Under negative ionization, the major molecular ion was [M - H](-). Higher clusters formed by two and three surfactant molecules, i.e. [2M - H](-) and [3M - H](-) were likewise registered. The tendency to form clusters in both positive and negative ion modes, even at 0.1 mg l(-1) levels, was attributed to strong electrostatic interactions between the zwitterionic head groups. Further evidence for this assumption was provided by the detection of a fragment formed from [2M - H](-) which contained the two charged head groups. Studies were undertaken in the negative ion mode on the concentration- and orifice voltage-dependent monomer, dimer and trimer formation of C(12)-CAPB in order to evaluate potential issues in using the ion [M - H](-) mode for quantitative analysis. Finally, the established (-)-LC/ESI-MS method was applied to follow up the primary degradation of CAPB in a laboratory-scale fixed-bed bioreactor (FBBR) spiked with a test concentration of 10 mg l(-1). Direct analysis without sample pretreatment revealed that higher alkyl homologues were more prone to adsorption. Primary biodegradation of all alkyl homologues was completed after a period of 4 days. Selected lyophilized FBBR samples were examined for the presence of transient or stable degradation intermediates, but no metabolite could be identified.

Changes in folate characteristics and its identification in broccoli (Brassica oleracea Italica) extract fermented by Lactic Acid Bacteria Mixed Culture (LAB)

“…Solvent was a mixture of water containing 0.3% acetic acid (A) and methanol containing 0.3% acetic acid (B) at a ratio of 80% methanol and 20% water with a flow rate of 1 mL/min. The injection volume 20 L was used in this analysis [15].…”

Purification and Components Identification on Spinach (Amaranthus sp. L.) and Broccoli (Brassica oleracea L.) Fermented by Kombucha Culture as Source of Folic Acid Through Stirred Microfiltration Cell (SMFC)

“…Analysis were performed on total solids (Gravimetric method), dissolved protein (Lowry method) [17], N-amino (Copper method) [18], total polyphenol (Folin-Denis Method) [19], folic acid (spectrophotometri UV-Vis) [20]. Identification on monomer biomass was conducted by LC-MS (Mariner Biospectrometry) with LC (Hitachi L 6200) [21]. Process and analysis were conducted in duplicate.…”

“…LC (Hitachi L 6200) using C18 (RP 18) Supelco column with long 250 x 2 mm and particles size 5 μm. Kinds of solvent were water containing 0.3 % Acetic Acid (A) and methanol containing 0.3 % Acetic Acid (B) at a 90 parts of methanol : 10 parts of water ratio at flow rate 1 mL/minute and injection volume of 20 μL [21].…”

“…This matter is caused by its presence of ionization because sensitify of LC-MS instrument relating with eluent used. Operation condition of LC-MS instrument is injection volume of 2 μL and flow rate 0.05 mL/minute with eluent mixtures of methanol and water (containing 0.3 % acetic acid) at ratio 80 : 20 using column of C-18 (15 mm x 1 mm) [21]. Identification on standard polyphenol as galic acid indicated chromatogram recovery with one (1) peak (T2.8) and relative intensity 100 % as displayed in Figure 4e, in which at mass spectra 111 -784 mz from peak T2.75 displayed dominant compound with MW 193.1289 Da.…”

Fermentation of Spinach (Amaranthus spp) and Broccoli (Brassica oleracea L.) Using Kombucha Culture as Natural Source of Folic Acid for Functional Food

“…Mobile phase consisted of aqueous acetic acid (0,3%) and methanol containing acetic acid 0,3% at a flow rate of 1,0 mL/min. An injection volume of 20 μL was used in this analysis [13].…”