44
S. Iftekhar et al.
Fig. 2.3 Summed-ion chromatograms for the analysis of wastewater effluents from sewage plants
by RPLC and electrospray-ionization mass spectrometry both without (a) and with (b) sample
pretreatment based on immunoextraction. The peaks labeled E1 and E2 represent estrone and
17β-estradiol, respectively, which were passed into the immunoextraction support along with their
deuterated forms, d 4 -E1 and d 4 -E2. Equilin was used as an internal standard along with its deuterated
form, d 4 -equilin. Adapted with permission from Ferguson et al. (2001). Copyright 2001 American
Chemical Society
Off-line immunoextraction was combined with LC and high resolution MS for the
detection and analysis of 8-isoprostaglandin F2α, an oxidative stress biomarker (Ryu
et al. 2015). In this work, sewage samples were spiked with an internal standard and
treated to deconjugate 8-isoprostaglandin F2α glucuronide. The samples were then
passed through a column containing monoclonal antibodies for 8-isoprostane that
were immobilized onto Sepharose. The analytes were eluted from the immunoaffinity column and placed into a solution of 20% acetonitrile in water. This was followed by analysis using a C18 RPLC column with high-resolution ESI-MS. The
detection limit for 8-isoprostaglandin F2α was 0.3 ng L
−1 , and immunoextraction allowed for the effective removal of interfering components from the sample
matrix (Ryu et al. 2015).
2.2.3 Online Immunoextraction
In online immunoextraction, a support and column containing immobilized antibodies are used to specifically extract one or more analytes and to directly transfer
these retained components to a second technique for analysis (Hage 1998). The
use of an online approach for immunoextraction helps to produce shorter analysis
times and higher reproducibility than off-line extraction (Nelson and Hage 2006).
Immunoextraction has frequently been combined online with RPLC (Thomas et al.
S. Iftekhar et al.
Fig. 2.3 Summed-ion chromatograms for the analysis of wastewater effluents from sewage plants
by RPLC and electrospray-ionization mass spectrometry both without (a) and with (b) sample
pretreatment based on immunoextraction. The peaks labeled E1 and E2 represent estrone and
17β-estradiol, respectively, which were passed into the immunoextraction support along with their
deuterated forms, d 4 -E1 and d 4 -E2. Equilin was used as an internal standard along with its deuterated
form, d 4 -equilin. Adapted with permission from Ferguson et al. (2001). Copyright 2001 American
Chemical Society
Off-line immunoextraction was combined with LC and high resolution MS for the
detection and analysis of 8-isoprostaglandin F2α, an oxidative stress biomarker (Ryu
et al. 2015). In this work, sewage samples were spiked with an internal standard and
treated to deconjugate 8-isoprostaglandin F2α glucuronide. The samples were then
passed through a column containing monoclonal antibodies for 8-isoprostane that
were immobilized onto Sepharose. The analytes were eluted from the immunoaffinity column and placed into a solution of 20% acetonitrile in water. This was followed by analysis using a C18 RPLC column with high-resolution ESI-MS. The
detection limit for 8-isoprostaglandin F2α was 0.3 ng L
−1 , and immunoextraction allowed for the effective removal of interfering components from the sample
matrix (Ryu et al. 2015).
2.2.3 Online Immunoextraction
In online immunoextraction, a support and column containing immobilized antibodies are used to specifically extract one or more analytes and to directly transfer
these retained components to a second technique for analysis (Hage 1998). The
use of an online approach for immunoextraction helps to produce shorter analysis
times and higher reproducibility than off-line extraction (Nelson and Hage 2006).
Immunoextraction has frequently been combined online with RPLC (Thomas et al.