Detection and determination of sulphones

M.-R. Fuh and K.-J. Chia, Determination of sulphonated azo dyes in food by ion-pair liquid chromatography with photodiode array and electrospray mass spectrometry detection. Talanta, 56 (2002) 663-671. 

R. El Hairak, M. Calull, R. M. Marce and R Boirull, Determination of naphthalene-sulphonates in water by on-line ion-pair solid-phase exti action and ion-pair liquid cliro-matography with diode-airay UV detection , Int. J. Environ Anal. Chem. 69 295-305 (1998). 

Detection in HPLC by ultraviolet absorption is commonplace and does not merit special mention here (see Section F.l below). There appear to be only few quantitative procedures for sulphones which are based on measurements of UV absorption. The final stage in a determination of the acaricide Sulphenone by Shuman29 was differential measurement of the absorption at 230,240 and 250 nm in isooctane solution. Kashiwa and... 

Various liquid chromatographic techniques have been frequently employed for the purification of commercial dyes for theoretical studies or for the exact determination of their toxicity and environmental pollution capacity. Thus, several sulphonated azo dyes were purified by using reversed-phase preparative HPLC. The chemical strctures, colour index names and numbers, and molecular masses of the sulphonated azo dyes included in the experiments are listed in Fig. 3.114. In order to determine the non-sulphonated azo dyes impurities, commercial dye samples were extracted with hexane, chloroform and ethyl acetate. Colourization of the organic phase indicated impurities. TLC carried out on silica and ODS stationary phases was also applied to control impurities. Mobile phases were composed of methanol, chloroform, acetone, ACN, 2-propanol, water and 0.1 M sodium sulphate depending on the type of stationary phase. Two ODS columns were employed for the analytical separation of dyes. The parameters of the columns were 150 X 3.9 mm i.d. particle size 4 /jm and 250 X 4.6 mm i.d. particle size 5 //m. Mobile phases consisted of methanol and 0.05 M aqueous ammonium acetate in various volume ratios. The flow rate was 0.9 ml/min and dyes were detected at 254 nm. Preparative separations were carried out in an ODS column (250 X 21.2 mm i.d.) using a flow rate of 13.5 ml/min. The composition of the mobile phases employed for the analytical and preparative separation of dyes is compiled in Table 3.33. 

High performance liquid chromatography (HPLC) has been widely used for many years in industrial laboratories but its use in environmental laboratories has usually been restricted to analyses such as the determination of polyaromatic hydrocarbons and linear alkylbenzene sulphonates. Traditionally gas chromatography (GC) has been the first choice technique and HPLC only used when GC has proved unsuitable, due to thermal lability or other reasons. This reliance on GC is despite the fact it has been reported that 80-90% of the total organic carbon content in waters is non-volatile and not amenable to GC. Probably the reason for the lack of use of HPLC lies in the poor sensitivity of its most common detector (UV spectrophotometric) compared with GC detectors and the often demanding limits of detection required for environmental analysis, where sub-pg 1 limits of detection are the norm. 

Reversed-phase HPLC with fluorescence detection, after derivatization of plasma thiols with ammonium 7-fluorobenzo-2-oxa-l,3-diazole-4-sulphonate (SBD-F), is the most widely used method to determine total plasma amino thiols (cysteine, cysteinylglycine, and homocysteine). The time required for sample preparation (thiolic reduction, deproteinization, and precolumn derivatization g with SBD-F) and for thiol derivatives separation is nearly 2 h per sample. =... 

The product was subjected to GLC for detection, e.g. of methanesulphonic acid in the presence of ethanesulphonic acid56, or for determination, e.g. of hexadecene-1- and 2-sulphonic acids57 or of alkylbenzenesulphonic acids58 or sulphonic acids in aerosols59. 

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