Material properties

Packing Material	1.8PBr
Silica Gel	Fully Porous Spherical High-Purity Silica	Surface Area (m2/g)	340
Particle Size (μm)	1.8	Bonded Phase	Pentabromobenzyl group
Pore Size (nm)	12	Bonding Type	Monomeric

Rapid separation of hydrophilic compounds using UHPLC

Rapid separation of purine metabolites

Using COSMOSIL PBr, the analysis of 9 purine nucleoside metabolites, including uric acid and allantoin, required approximately 40 minutes. Changing to COSMOSIL 1.8PBr, packed with smaller particles, allowed the analysis to be completed in approximately 10 minutes with equivalent separation.

Conditions
Column size	4.6 mm I.D. × 250 mm	Temperature	30°C
Mobile phase	Methanol / 0.1% Formic acid aq. = 10 / 90	Detection	UV 240 nm
Flow rate	PBr ; 1.0 mL/min, 1.8PBr ; 0.4 mL/min	Inj. Vol	1.0 μL
Sample	Allantoin Guanine Hypoxanthine Uric acid Xanthine Adenosine Inosine Guanosine Xanthosine

Hydrophilic compound retention by interaction with bromine

COSMOSIL PBr columns can be used in the same reversed‑phase mode as ODS columns; however, due to the high polarizability of bromine atoms, it exhibits unique retention and separation behavior. This is attributed to dispersion interactions and the recently recognized halogen bonding, which differ from conventional ODS columns. These interactions occur between highly polarizable atoms and π-electrons, as well as oxygen or nitrogen atoms possessing lone electron pairs. As a result, PBr columns can retain hydrophilic compounds that are difficult to retain on ODS columns, and enable the analysis of difficult compounds.

Imidazole dipeptide analysis

Conditions
Column size	2.1 mm I.D. × 100 mm	Temperature	40°C
Mobile phase	20 mM Ammonium formate aq.	Detection	UV 220 nm
Flow rate	0.2 mL/min	Inj. Vol	0.5 μL
Sample	L-Carnosine L-2-Oxocarnosine L-Anserine L-Balenine

Nicotinamide metabolite analysis

Conditions
Column size	2.1 mm I.D. × 100 mm	Temperature	30°C
Detection	UV 260 nm	Mobile phase	A ; Methanol / 20 mM Ammonium formate aq. = 5 / 95 B ; Methanol / 20 mM Ammonium formate aq. = 20 / 80 B conc. gradient ; 0% (0 → 3 min), 100% (3 → 6 min), 100% (6 → 10 min)
Flow rate	0.3 mL/min	Inj. Vol	1.0 μL
Sample	NAMN NMN ATP IMP NR Cytidine NA NAD+ Inosine NAD NAM

Differences in separation characteristics due to stereoselectivity compared to ODS columns

With COSMOSIL PBr columns, selectivity derives not only from π-interactions of aromatic rings and dispersion interactions with bromine, but also structural configuration of the analytes. These effects can lead to improved separation on PBr columns, even when retention on ODS columns is sufficient.
* Taniguchi A, et al. Chromatography. 2025;46:55.

Malodorous aldehyde derivative analysis

In the analysis of odorous aldehyde derivatives regulated under Japan’s Offensive Odor Control Law, separation of certain isomers can be challenging. When using conventional reversed-phase columns, complex analytical conditions, such as a threecomponent mobile‑phase gradient, have been used. In contrast, analysis can be performed using 1.8PBr under simpler isocratic conditions using a two‑component mobile phase.

Conditions
Column size	2.1 mm I.D. × 100 mm	Temperature	30°C
Mobile phase	Methanol / Water = ＊＊ / ＊＊ ODS = 75 / 25 PBr = 90 / 10	Detection	UV 360 nm
Flow rate	0.3 mL/min	Inj. Vol	0.4 μL
Sample	Formaldehyde Acetaldehyde Propionaldehyde iso-Butyraldehyde n-Butyraldehyde iso-Valeraldehyde n-Valeraldehyde

Differences in separation characteristics compared to PFP columns

PBr columns and pentafluorophenyl (PFP) columns both contain halogenated benzene. However, because PFP relies on dipole– dipole interactions, while PBr retains compounds primarily through dispersion interactions, their separation characteristics differ significantly. Both PFP and PBr columns showed improved separation compared to ODS columns, but the elution order was different. PFP exhibited strong retention of the fluorinated groups, -CF₃ and ‑SF₅, while PBr exhibited strong retention of the heavy halogen groups, -Br and ‑I, through dispersion interactions.

Conditions
Column size	4.6 mm I.D. × 150 mm	Sample	Trifluorotoluene (R = CF3) Toluene (R = CH3) Bromobenzene (R = Br) Phenylsulfur pentafluoride (R = SF5) Iodobenzene (R = I)
Mobile phase	Methanol / Water = ＊＊ / ＊＊ ODS = 70 / 30 PFP = 60 / 40 PBr = 70 / 30
Flow rate	1.0 mL/min
Temperature	30°C
Detection	UV 254 nm
Inj. Vol	1.0 μL

Purity of synthetic peptides

Conditions
Column size	2.1 mm I.D. × 100 mm	Sample	H-(D-Arg)n-NH2 n = 6 n = 7 n = 8
Mobile phase	A ; 0.1% TFA in water B ; 0.08% TFA in acetonitrile B conc. gradient ; 0 - 15% (0 - 15 min)
Flow rate	0.2 mL/min
Temperature	40°C
Detection	UV 220 nm

Separation of adenosine phosphates

Conditions
Column size	2.1 mm I.D. × 100 mm	Sample	Adenosine-5’-triphosphate (ATP) Adenosine-5’-diphosphate (ADP) Adenosine-5’-monophosphate (AMP)
Mobile phase	20 mM Ammonium formate aq.
Flow rate	0.4 mL/min
Temperature	40°C
Detection	UV 260 nm

Separation of isomers of highly hydrophilic compounds

Conditions
Column size	2.1 mm I.D. × 150 mm	Sample	1-Methyl imidazole 2-Methyl imidazole 4-Methyl imidazole
Mobile phase	0.1% Formic acid aq.
Flow rate	0.4 mL/min
Temperature	40°C
Detection	UV 220 nm

Separation of sugars

Conditions
Column size	2.1 mm I.D. × 150 mm	Sample	Glucose Trehalose Sucrose Melezitose Raffinose Stachyose
Mobile phase	Water
Flow rate	0.4 mL/min
Temperature	40°C
Detection	ELSD

Our UHPLC columns use the same connectors as Waters UPLC^® (UHPLC) columns. This is different from our conventional COSMOSIL columns, which use the conventional Waters HPLC-compatible connectors. Attempting to connect an unsuitable fitting may result in it becoming stuck in the column.

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COSMOSIL PBr series

Information on other UHPLC series

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