Page 24 - Shimadzu Journal vol.2 Issue1

Topics Topics

In addition to five reversed phase separation modes, including 3. Mechanism behind Co-Sense for BA Fig. 5 shows the recovery rates and peak shapes when a dilution
High-Throughput Bioanalysis with On-Line Sample ODS, the Shim-pack MAYI series provides a strong cation Fig. 3 shows the flow schematic for Co-Sense for BA. The standard trap is used with indomethacin samples likewise spiked with
Pretreatment Using Restricted Access Media exchange mode and a strong anion exchange mode (Table 1). configuration adopts a sample injection method based on the plasma, and large-volume 100 µL, 200 µL, and 500 µL samples are
The Shimadzu Co-Sense for BA System Solution dilution trap method, to ensure reliable trapping and injected. Even with the 500 µL injection, a recovery rate of almost
Table 1 Stationary Phases and Separation Modes in the concentration of intended components. 100 % is achieved, and the peak shape is maintained.
Shim-pack MAYI Series
While the sample injected from the autosampler is introduced to
1. Introduction Product Name Stationary Phase Separation Mode the trap column via the mobile phase from the pump unit for
Because of its high sensitivity and selectivity, analysis via LC/MSMS Shim-pack MAYI-ODS(G) Octadecyl Reversed Phase sample injection (a), it is diluted automatically by the dilution
is now widely used in the context of pharmacokinetic research, Shim-pack MAYI-C14(G) Tetradecyl Reversed Phase solvent delivered from the pump unit for on-line dilution (b), and
drug metabolism research, bioequivalence tests, and other Shim-pack MAYI-C8(G) Octyl Reversed Phase introduced to the trap column, the Shim-pack MAYI column (c).
measurements of drug concentrations in biological samples Shim-pack MAYI-C4(G) Butyl Reversed Phase Thanks to this dilution process, interactions with the matrix and
(bioanalysis). However, in more than a few situations, there are Shim-pack MAYI-C1(G) Methyl Reversed Phase the impact of the sample solvent are suppressed, while the
problems with impurities such as proteins originating from Shim-pack MAYI-SCX(G) Sulfonate Strong Cation Exchange Mode intended components are introduced to the trap column, thus
organisms; ionization suppression caused by matrix effects; Shim-pack MAYI-SAX(G) Trimethylammonium Strong Anion Exchange Mode providing reliable trapping and concentration. A liquid containing
ionization enhancement; degradation of precision, accuracy, and a buffer solution and a low-concentration organic solvent is used
reproducibility; and carryover. Accordingly, sample pretreatment Note: "Co-Sense for BA", the name of this product, is an The stationary phase is selected in accordance with the polarity of as the dilution solvent.
methods have become a very important topic of investigation. abbreviation of "the Collaboration of Shimadzu and Eisai for New the target compound. However, the type of extraction solvent Intended components concentrated in the trap column are
Conventionally, the following have been utilized as serum and Systematic Efficiency." "Co-Sense" refers to "collaboration of from the column and the trap dilution solvent must also be introduced to the analysis line via valve switching. The mobile
plasma pretreatment methods, primarily with the objective of sensibilities" the concept behind this product. This refers to the investigated [5], [6], [13]. In investigations utilizing the strong phase from the pump unit for analysis (d) then delivers them to
deproteinization. integration of user and manufacturer to create new value. In cation exchange mode (SCX), a variety of evaluations have been the analysis column (e) where they are separated and analyzed. In
addition, the MAYI pretreatment column is named using the initials performed. These include the recovery rate of differing pKa addition to UV and PDA detectors, MS detectors can also be
1) Addition of acids or organic solvents to denature proteins and of the four researchers at Eisai responsible for developing it. compounds in plasma, evaluation of the decrease in matrix effects connected.
render them insoluble, for removal by centrifuging in MS detection, and evaluation of metabolites in rat bile through
combination with a C4 column [7], [8], [9]. In investigations E
2) Physical removal using ultrafiltration membranes 2. Methylcellulose-Immobilized Pretreatment Column, utilizing the strong anion exchange mode (SAX), results have been
3) Off-line pretreatment using solid phase extraction cartridges ɹ Essential to Co-Sense for BA evaluated related to the analysis of aspirin and its metabolites F
(such as acetylsalicylic acid) in rat plasma [10].
4) On-line pretreatment using solid phase extraction columns Operating Principles Behind the Shim-pack MAYI Series of
Biological Sample Pretreatment Columns With an optimized particle size and a special coating technique,
the Shim-pack MAYI column provides a high protein removal
In method (1), it is important to evaluate whether the drugs are The outer surface of the silica gel (50 um) is coated with a efficiency and long-term stability. In addition, by increasing sample
denatured, while in method (2), adsorption by raw materials must water-soluble polymer (Methylcellulose). Only the pore interior is permeability, the occurrence of pressure increases (clogging) due D
be evaluated. When considering treatment time, cost, and data chemically modified by octadecyl or other functional groups [5]. to adsorption of sample components has been suppressed, and
reproducibility, method (4), which can be implemented on-line, Macromolecules such as proteins are blocked by the water-soluble excellent reproducibility is shown, even in consecutive
seems the most likely to increase overall productivity. polymer layer on the outer surface and do not enter the pores. As multi-sample analysis. Fig. 2 shows the changes to the
a result, they are not retained by the stationary phase, and are
In terms of pretreatment columns in method (4), in addition to chromatogram when an isopropylantipyrine sample spiked with
reversed phase mode, normal phase mode, and ion exchange quickly eluted. In contrast, drugs and other typical organic low plasma is injected 300 times. Essentially the same chromatogram B C
mode, columns classified by restricted access media (RAM) are molecular compounds penetrate into the pores, and are retained is obtained, even after 300 injections. This series consists of
now utilized. Product types have also increased, and have been by the stationary phase on the inner surface. They are then eluted cartridge type columns, which are attached to a special column
subject to review [1], [2]. RAM is a highly functional packing under appropriate conditions and analyzed with the analysis holder. Fig. 3 Flow Schematic for the Standard Configuration of
material, designed so that the outer surface of the packing column. Fig. 1 shows the behavior of drugs (low-molecular In addition to these, Eisai has also evaluated weak cation Co-Sense for BA
particles removes proteins and other biological macromolecules, compounds) and proteins at the surface of the packing material in exchange mode columns [11].
restricting their internal penetration. Conversely, the internal pores the Shim-pack MAYI-ODS. 4. Effective Trapping and Concentration Using a Dilution Solvent
or inner surface captures the target low molecular compounds.
With Co-Sense for BA, the injected sample is diluted at a constant
In conjunction with Eisai Co., Ltd., Shimadzu has developed and rate. This is performed to suppress interactions between intended
commercialized unique restricted access type trap columns components and proteins in the sample, and to release intended
(Shim-pack MAYI series) classified as RAM, and an LC system with components bound to proteins. In this way, even components
on-line pretreatment functionality via valve switching (Co-Sense with a high binding rate are reliably trapped and concentrated. A
for BA). The Co-Sense for BA allows large volumes of plasma, liquid containing a buffer solution and a low-concentration
serum and other biological samples to be injected and analyzed. organic solvent is used as the dilution solvent. As a result, even
High-concentration proteins and electrolytes, which are plasma and serum samples can be injected directly. In addition,
unnecessary components, are almost completely removed. Since high sensitivity is achieved due to excellent recovery rates and
pretreatment involves direct injection, there is no loss of valuable peak shapes, even for large-volume injections [6], [7], [9], [10],
samples, and stable data can be obtained even with unstable [12], [13].
components. Further, the adoption of dilution trap method Fig. 4 shows a comparison of recovery rates based on the presence
maintains peak shape and enhances sensitivity by concentrating or absence of on-line dilution, utilizing indomethacin samples
the intended components, thereby providing stable recovery rates spiked with plasma. With dilution, the recovery rate is almost 100
and reproducibility [3], [4], [5], [6], [7]. These features effectively Fig. 2 Evaluation of the Durability of the Shim-pack MAYI-ODS %. Without dilution, the recovery rate falls to approximately 50 %.
result in the protection of analysis columns and the LC/MS
interface, as well as the reduction of matrix effects, enabling the
acquisition of efficient, highly reliable results [8].
Fig. 1 Behavior of Drugs (Low-Molecular Compounds) and
Proteins at the Surface of the Shim-pack MAYI-ODS

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