Mds sciex 5800 maldi tof tof analyzer

The molecular weight and the haptenation ratio (the hapten:carrier protein molar ratio) were calculated [((MW hapten + carrier protein) – MW carrier protein)/MW of hapten] for each conjugate using an Applied Biosystems/MDS SCIEX 5800 MALDI TOF/TOF analyzer (Foster City, CA) and TOF/TOF 5800 System Software (SCIEX, Concord, Ontario, Canada). The instrument operated in a high-mass linear mode. Samples were desalted on a ZipTip C4 (Merk Millipore, Burlington, MA) prior to analysis. Bovine serum albumin (BSA) was used to calibrate the instrument.

The molecular weight (MW) of BSA and CRM-containing conjugates was assessed before and after conjugation using an Applied Biosystems/MDS SCIEX 5800 MALDI TOF/TOF analyzer (Foster City, CA) and TOF/TOF 5800 System Software (SCIEX, Concord, Ontario, Canada). Each sample was assigned a spot and mixed with a saturated sinapinic acid matrix on a 384 opti-tof 123 × 81 mm Rev A plate. Data were acquired in the linear high mass positive acquisition mode. The resulting haptenization ratio (number of haptens per mole of protein) of each conjugate was calculated as follows: [(MW_conjugate − MW_{carrier protein})/MW_hapten]. Due to their large molecular weight, the haptenization ratio of sKLH conjugates could not be determined by MALDI-TOF and was consequently characterized for size by DLS on a Zetasizer (Malvern Panalytical Inc., United Kingdom) as described previously.⁴⁷