Silica Based SPE-Orpheus
 
Silica based SPE sorbents
Features: 
Available in all product formats (discs and packed particle bed cartridges, columns, 96 and 384 well plates)
Broader analyte selectivity via retention of both hydrophobic and hydrophilic moieties due to hydrophilic character of bonded particle
Less Silanol activity 
Available in 60-300 Å porosities 
Wide varieties of phases: Non-polar, Ion Exchanged, Mixed Modes
Applications: 
Specific phases for routine extractions of drugs of abuse from biological fluids
Highest mass cartridges for extractions of environmental samples. 
Sorbent Selection:  Reversed Phases
C1
C2
C8
C18
Phenyl
Cyclohexyl
Polar Phases
Silica
Diol
Cyanopropyl
Alumina
Amino
Florisil
Ion Exchange Phases
SCX
SAX
Diethyl Aminopropyl
        (DEAP– WAX)
Carboxylic Acid
         (CBA-WCX)
Formats: 
SPE Cartridges
LRC Columns
Snap Cap Cartridges
SPE Plate - 1ml
SPE Plate - 2ml
www.orochem.com
Silica based SPE sorbents
  Evaluation Model for Identification of Distinctive Silanol Variations in SPE Sorbents Used for LC-MS/MS Bioanalytical Sample Preparation
Introduction:
Solid-phase extraction (SPE) is a powerful sample preparation method to isolate pure analyte and minimize ion suppression from matrix components when using LC-MS/MS techniques. Successful use of bonded silica sorbents often requires extensive time in method development to overcome secondary effects on the silica surface. Elution solvents with triethylamine (TEA) are often required to disrupt strong silanol retention. Rapid “on/off” sample preparation prefers solvent modifications be unnecessary and that elution be performed with common organic solvents for compatibility with MS. We designed an evaluation model using probes to characterize silanol content. Most importantly, significant differences have been shown to exist in spite of end capping.
 
Methods
A collection of branded sorbent particles (C8 and C18 bonded silica) was evaluated for their relative silanol content in a simple model using three probes dissolved in water: amitriptyline (50 ug/mL), acetylsalicylic acid (10 ug/mL) and Azure A (2 ug/mL). Following SPE cartridge (200 mg/3 mL size) conditioning, analyte probes were loaded and washed with water; both
Preliminary Data
Elution of amitriptyline (basic amine-containing probe) from C8 and C18 sorbents often requires a TEA-modified solvent  to disrupt   silanol interactions. Examination of elutes from different SPE sorbents clearly showed distinct differences among brands. Two C8 types eluted amitriptyline with pure acetonitrile (24% and 62%    recovery), while two others showed no recovery (high silanol content), and two additional brands did elute using TEA in organic solvent. Among seven C18 silica types, one showed 91% recovery using acetonitrile elution, two showed 20% and 22% recovery, and the remaining displayed no recovery.
Retention of acetyl salicylic acid (a carboxylic acid probe) on C8, C18 and silica were compared. Breakthrough was 100% for silica, while four C8 brands showed 0%, 0%, 5% and 68%; clear differences in silanol content were demonstrated. Seven C18 brands revealed breakthrough percentages of 25%, 25%, 43%, 45%, 65%, 88% and 98%, confirming sorbent diversity.
Retention of Azure A (aromatic amine-containing probe) on the same    sorbents was also compared. On two sorbents the dye eluted with 20%      acetonitrile in water; the remaining required TEA-modified acetonitrile.
Retention and Elution of Amitriptyline applied to C18
Sorbent Breakthrough% Elute Ch3CN%
Elute Mobile Phase w/TEA %
Orochem 0 91 9
Sorbent B 0 0 100
Sorbent Z 0 20 80
Sorbent R 0 0 100
Sorbent C 0 0 100
Sorbent A 0 0 100
Sorbent M 0 22 78
Retention of Acetylsalicylic Acid on C8 Not- Endcapped Sorbents
Sorbent Breakthrough
Silica 10 µg/ml
Orochem 1 0%
Orochem 2 Polar 0%
Sorbent Z 6.8% µg/ml
Sorbent S  0.54 µg/ml
Retention of Acetylsalicylic Acid on C18 Not- Endcapped Sorbents
Sorbent Breakthrough µg/ml
Silica 10
Orochem  2.5
Sorbent Z 4.3
Sorbent R 4.5
Sorbent B  8.8
Sorbent C 6.5
Sorbent A 9.6