| HS Code | 570390 |
| Product | Toluene |
| Brand Quality | CHROMASOLV™, for HPLC |
| Purity | ≥99.9% |
| Cas Number | 108-88-3 |
| Molecular Formula | C7H8 |
| Molecular Weight | 92.14 g/mol |
| Boiling Point | 110.6 °C |
| Melting Point | -95.0 °C |
| Density | 0.865 g/mL at 25 °C |
| Refractive Index | 1.496 at 20 °C |
| Flash Point | 4 °C (closed cup) |
| Solubility In Water | Slightly soluble, ~0.53 g/L at 20 °C |
As an accredited Toluene, CHROMASOLV™, for HPLC, ≥99.9% factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Toluene CHROMASOLV™ for HPLC is supplied in 1 L amber glass bottles, tightly sealed to preserve ≥99.9% purity. |
| Container Loading (20′ FCL) | 20′ FCL of Toluene (HPLC grade): load secured drums/IBCs, flammable, ventilate, ground/braced, prevent shifting, UN compliant. |
| Shipping | Shipped as a hazardous flammable liquid, UN1294, Class 3, Packing Group II. Packaged in tightly sealed glass bottles or steel drums with hazard labels and documentation. Transport requires compliance with IATA, IMDG, and ADR regulations. Keep away from heat, sparks, and open flame; ensure proper grounding during transfer. |
| Storage | Store in a tightly sealed, original container in a cool, dry, well-ventilated area away from direct sunlight, heat sources, and open flames. Keep separate from strong oxidizers. Ensure proper grounding for dispensing. Maintain temperature stability to preserve HPLC purity, and strictly avoid contamination. Follow all local regulations and safety data sheet guidelines for flammable solvents. |
| Shelf Life | Shelf life is typically 3–5 years when stored tightly sealed in original container, away from light and heat. |
Hydrocarbon resin and hot-melt adhesive producers running ambient gel permeation chromatography with refractive index detection select toluene CHROMASOLV™ as the eluent for medium-polarity tackifier samples that aggregate in pure tetrahydrofuran. The solvent is supplied with an assay of ≥99.9%, water ≤0.03%, and evaporation residue ≤5 mg/L. The analytical train comprises a 300 mm × 7.8 mm column packed with 5 µm cross-linked polystyrene-divinylbenzene particles, an inline vacuum degasser, and a differential refractometer thermostatted at 35 °C. Samples are dissolved at 2.0 mg/mL in the same toluene batch and injected at 20 µL. Eluent flow is 1.0 mL/min with backpressure 3.5–4.0 MPa. Calibration is performed against narrow-dispersity polystyrene standards dissolved in the same solvent batch. Water content is held below 0.03% because adsorbed water on the column frit changes the elution volume of oligomeric fractions between 500 g/mol and 5,000 g/mol. This boundary is critical when the terminal product is a pressure-sensitive adhesive in which tackifier molecular weight distribution controls peel adhesion and shear adhesion failure temperature. Operators prefilter each mobile-phase batch through a 0.45 µm PTFE membrane and sparge with helium for 10 min before use. If the reservoir is left open, ambient moisture uptake can raise water content above 0.05% within 8 h at 55% relative humidity and shift low-molecular-weight tail retention volumes by up to 0.4 mL. ISO 16014-1:2019 allows toluene as an eluent where compatibility with the polymer sample is demonstrated.
In nitration reactor streams, agrochemical contract laboratories quantify 2-chloronitrobenzene, 3-chloronitrobenzene, and 4-chloronitrobenzene using a toluene-modified normal-phase mobile phase because the solvent reduces silanol tailing of the nitroaromatic ring. A 250 mm × 4.6 mm column packed with 5 µm unbonded silica is thermostatted at 30 °C. The mobile phase is n-hexane/toluene 80:20 v/v for isocratic resolution of the meta isomer or 75:25 v/v when the ortho isomer elutes too close to the solvent front. Injection volume is 10 µL and UV detection is set at 254 nm. Toluene with water above 0.03% causes baseline drift because water partitions onto silanol sites unevenly and alters local retention equilibrium. Column equilibration at 1.0 mL/min for 30 min is required after exposure to dry solvent. Terminal output is a nitration intermediate for dyes and crop-protection actives; off-spec isomer ratios above 0.5% w/w relative to the dominant isomer require re-distillation or re-crystallization. Method validation follows ICH Q2(R1) with linearity evaluated over five calibration levels from 0.05 mg/mL to 2.0 mg/mL.
Refinery laboratories use toluene as the aromatic solvent in saturate, aromatic, resin, and asphaltene separation of vacuum gas oils, bitumen, and lubricant base stocks. The sample is dissolved in n-heptane at 10 mg/mL; asphaltenes are precipitated, filtered, and quantified gravimetrically. The maltene fraction is separated on a 250 mm × 4.6 mm cyano-bonded silica column using sequential elution with n-heptane, toluene, and dichloromethane at 1.0 mL/min. Differential refractive index detection at 35 °C and UV detection at 254 nm are connected in series. The toluene segment must contain less than 0.03% water and less than 1 ppm chloride to avoid irreversible adsorption of resins onto the stationary phase. The solvent is degassed before the pump inlet because toluene outgasses when blended with heptane. Results are expressed as weight percent saturates, aromatics, resins, and asphaltenes and feed catalytic cracking unit models and asphalt binder compatibility specifications. ASTM D7419-18 defines the HPLC refractive index determination of total aromatics and total saturates in lubricant base oils with toluene-containing mobile phases; ASTM D2007-19 describes clay-gel adsorption for rubber extender and processing oils using toluene as the aromatic desorbent. Terminal products include vacuum gas oil hydrotreater feed, paving-grade bitumen, and API Group II base oil.
For arc-discharge soot extracts containing fullerenes, carbon nanomaterial producers select toluene CHROMASOLV™ because it dissolves C60 and C70 without mobilizing insoluble graphite particles. The extract is prepared at 1.0 mg/mL in toluene, filtered through 0.2 µm PTFE, and protected from light. A 250 mm × 4.6 mm column packed with 5 µm pyrenylpropyl-bonded silica is eluted with a toluene/methanol mobile phase at 30 °C. The toluene/methanol ratio is adjusted between 50:50 v/v and 70:30 v/v according to column lot. UV detection is set at 384 nm. The terminal product is a mixed fullerene reference material used in organic photovoltaic module development and antioxidant research. When water content rises above 0.03%, the C60 peak symmetry degrades from 1.2 to more than 1.8 and the C70 shoulder can become unresolved. Solvent reservoirs are fitted with molecular sieve drying traps; waste toluene is recovered by distillation at 110.6 °C and is not discharged to biological treatment. When the mixed fullerene material is certified as a reference material, production documentation follows ISO 17034:2016. Published data for specific column-lot ratios is limited because pyrenylpropyl phases vary in surface coverage.
When medical device laboratories replace dichloromethane with toluene in exhaustive extraction of polycarbonate infusion-pump housings, they select HPLC-grade toluene because it produces a cleaner extract in GC-MS and LC-MS screening for bisphenol A, diphenyl carbonate, and organophosphite degradation products. The polymer is cryomilled to a particle size below 500 µm. A borosilicate Soxhlet apparatus is loaded with 25 g of milled polymer and 200 mL of toluene. Extraction proceeds for 8 h at 110 °C with 6 cycles/h. The extract is concentrated under nitrogen at 40 °C to 1.0 mL and reconstituted for split injection. Toluene cannot be used for whole-part immersion without milling because it swells polycarbonate, slows solvent penetration, and traps oligomers in the glassy matrix. The extractables profile is evaluated against ISO 10993-18:2020 and sample preparation requirements in ISO 10993-12:2021. Terminal product is a polycarbonate housing accepted for infusion-pump structural use after toxicological risk assessment. The solvent batch must meet the manufacturer’s UV transmittance specification; for toluene CHROMASOLV™, this is measured at 286 nm with a 1 cm path length.
| Application track | Critical solvent parameter | Reference method or standard | Operational boundary |
|---|---|---|---|
| Ambient GPC of tackifier resins | Water content ≤0.03% | ISO 16014-1:2019 | PTFE filtration 0.45 µm; helium sparge |
| Normal-phase isomer resolution | Water content ≤0.03%; assay ≥99.9% | ICH Q2(R1) | Silica column pre-equilibration 30 min |
| SARA fractionation | Chloride <1 ppm | ASTM D7419-18, ASTM D2007-19 | Degas before blending with heptane |
| Medical device extractables | UV transmittance at 286 nm | ISO 10993-18:2020, ISO 10993-12:2021 | Cryomill below 500 µm before extraction |
During installation and operational qualification of UV-Vis HPLC detectors, regulated contract laboratories use dilute toluene solutions as a detector response standard. A stock solution is prepared at 0.05% v/v in n-hexane and diluted to five levels from 0.005% v/v to 0.05% v/v. An autosampler injects 10 µL into a 254 nm detector channel with the column removed. Peak area is plotted against concentration; acceptance is linearity with r² > 0.999 and repeatability RSD ≤2.0% across six injections under USP <621>. Toluene is used because it contains no basic nitrogen that can adsorb to flow cell walls and its absorbance at 254 nm is strong enough to detect low-level stray light without saturating the detector at these dilution levels. The terminal output is a system suitability record supporting batch release in pharmaceutical quality control. The same toluene batch is also suitable for wavelength accuracy checks using the 268 nm absorbance band. If the solvent is contaminated with benzene, detector response at 215 nm increases disproportionately and linearity at low levels fails.
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Toluene, CHROMASOLV™, for HPLC, ≥99.9%, is a high-purity aromatic hydrocarbon solvent supplied for use as a mobile-phase component or sample diluent in liquid chromatography. The material is identified by Chemical Abstracts Service number 108-88-3, empirical formula C7H8, and molar mass 92.14 g/mol. The product designation includes a gas-chromatographic assay criterion of ≥99.9% area normalization, which places it above general-purpose reagent toluene and aligns it with normal-phase HPLC, size-exclusion chromatography, and related separation workflows in which low water, low non-volatile residue, and controlled ultraviolet background are required. The solvent is supplied with a lot-specific certificate of analysis covering assay, water, evaporation residue, and UV absorbance data. The grade is intended for isocratic and gradient HPLC systems operated with ultraviolet, photodiode-array, refractive-index, or light-scattering detection, subject to the solvent’s ultraviolet cutoff and system compatibility requirements.
In normal-phase HPLC, toluene functions as a weak eluent with a solvent strength parameter ε° on bare silica of 0.29 and a polarity index of 2.4. These values place it between heptane, with ε° 0.01, and dichloromethane, with ε° 0.42, making toluene useful for selectivity adjustment where aliphatic hydrocarbons provide insufficient retention control for aromatic analytes. The viscosity of toluene at 25 °C is 0.56 mPa·s, and the boiling point is 110.6 °C. The flash point is 4 °C, and explosive limits in air are 1.1–7.1 vol%. These properties require that mobile-phase preparation, degassing, and waste handling be conducted with controls appropriate for flammable solvents. Toluene is practically immiscible with water; its solubility in water is approximately 0.47 g/L at 20 °C, and the corresponding saturation of water in toluene at ambient temperature is a critical factor in the control of normal-phase retention.
| Parameter | Method | Limit |
|---|---|---|
| Assay, as C7H8 | GC-FID, area normalization | ≥99.9% |
| Water | Coulometric Karl Fischer titration, ISO 760 | ≤0.03% |
| Evaporation residue | Gravimetric, 100 mL sample | ≤0.0005% |
| UV absorbance | Spectrophotometry, 1 cm path against water | Lot-specific; reported at 285 nm and 300 nm |
| Density at 25 °C | Oscillating U-tube, ASTM D4052 | 0.862–0.868 g/mL |
The GC-FID assay does not detect nonvolatile salts or oligomeric material; the evaporation residue and UV absorbance tests are therefore separate controls. Water is determined by coulometric Karl Fischer titration because toluene is non-conducting, and volumetric Karl Fischer may lack sufficient precision at the 0.03% level. The low water limit is not arbitrary. Water is only sparingly soluble in toluene at ambient temperature, and the specification approaches saturation. The consequence is that minor cooling or humid air ingress can create a separate water phase, producing detector baseline disturbances that are not necessarily detected by a simple water-content average.
Water control in toluene-containing normal-phase eluents creates a processing window narrower than in reversed-phase systems. On a bare silica column with dimensions 250 mm × 4.6 mm, packed with 5 µm particles and operated at 1.0 mL/min at 30 °C, the adsorbed water layer on silica acts as a polar moderator. When mobile-phase water content rises from 0.01% to 0.03%, retention factors for polar neutral analytes can decrease by more than 10%, and selectivity between nitroaromatic positional isomers can shift. Conversely, a dry toluene mobile phase with water below 0.005% often produces long retention and peak tailing because active silanol sites are not partially deactivated. The ≤0.03% specification places the solvent near the water-saturation boundary of toluene, which is approximately 0.033% at 25 °C. Cooling below ambient temperature or humid air ingress can create micro-droplets that scatter light in flow cells and produce baseline spikes. Vacuum degassing must therefore be temperature-controlled; sudden pressure drops can release dissolved water as gas-phase water, causing pump cavitation at low flow rates. Helium sparging at 20–25 °C is preferred for long sequences. If the chromatographic method requires a true dry toluene, the HPLC grade should not be assumed sufficient; a separate anhydrous grade or a molecular-sieve drying train is required, with the caveat that sieves may contribute particulates.
Because toluene itself strongly absorbs below its cutoff near 286 nm, the solvent cannot be used as a neat mobile phase for detection at 254 nm, a standard wavelength for aromatic impurities. At 285 nm, a 1 cm path length may show lot-specific absorbance close to 1.0 AU against water; at 300 nm, absorbance falls below approximately 0.5 AU. Baseline stability therefore improves when the detection wavelength is set at 290 nm or higher. In a typical method using a photodiode-array detector with a 10 mm flow cell, a slow increase in baseline at lower wavelengths may be observed as the mobile-phase composition changes during gradient elution. When a gradient from heptane to toluene is used, the detector reference wavelength should be chosen above 286 nm; if detection at 254 nm is mandatory, the gradient should be redesigned to avoid high toluene fractions. This limitation is a property of toluene and not specific to the CHROMASOLV™ grade; the grade controls impurities but does not shift the solvent’s electronic absorption cutoff.
Low-pressure gradient mixing with toluene as a strong component is affected by compressibility and viscosity differences relative to heptane. Toluene viscosity at 25 °C is 0.56 mPa·s, compared with approximately 0.39 mPa·s for heptane. In quaternary HPLC pumps, proportioning valves may require extended fill strokes when switching from heptane to toluene; solvent compressibility settings should be configured according to the pump manufacturer’s control parameters. A practical priming sequence is to flush each line with 10 mL at 5 mL/min and then run a blank gradient before sample injection. Failure to do so can produce retention-time drift during the first runs of a sequence, particularly on amino and bare silica columns that retain small amounts of water or polar modifier.
Compared with general-purpose reagent toluene, the CHROMASOLV™ for HPLC grade adds particulate filtration and lot-specific UV and residue testing. Reagent-grade toluene may have a GC assay of 99.5% but can contain higher water, non-volatile residue, and UV-absorbing impurities that appear as unknown peaks or rising baseline in gradient HPLC. ACS-grade toluene controls common impurities but is not optimized for HPLC; it may not include UV absorbance specifications at HPLC wavelengths. Anhydrous toluene controls water below 0.005% but may not be tested for evaporation residue or UV background. By contrast, the for-HPLC grade is specified for water ≤0.03%, residue ≤0.0005%, and UV absorbance at defined wavelengths. For LC-MS use, LC-MS-grade toluene provides additional controls for metal ions, sodium, potassium, and phthalate background. The for-HPLC grade should not be assumed to meet those LC-MS constraints. Published data for this specific configuration is limited; no generic equivalence should be inferred without reviewing lot-specific certificates from both grades.
| Property | Value | Operational relevance |
|---|---|---|
| UV cutoff | 286 nm | Minimum practical detection wavelength |
| Polarity index | 2.4 | Selectivity relative to heptane |
| Solvent strength ε° on silica | 0.29 | Mobile-phase strength in normal-phase HPLC |
| Viscosity at 25 °C | 0.56 mPa·s | Column backpressure and mixing |
| Boiling point | 110.6 °C | Degassing and evaporation |
| Flash point | 4 °C | Flammability control |
| Explosion limits in air | 1.1–7.1 vol% | Ventilation and electrical classification |
In polymer and additive analyses, toluene is used as the dissolution solvent and mobile phase in size-exclusion chromatography. A typical arrangement uses a styrene-divinylbenzene copolymer column set with a refractive-index detector and a flow rate of 1.0 mL/min at 35 °C. The low water content reduces light-scattering baseline artifacts, and the evaporation residue specification minimizes deposits on SEC guard columns. However, the for-HPLC grade is not certified for low total-ion-current background in mass-selective detection and should not be substituted for an LC-MS grade when trace-level electrospray or atmospheric-pressure chemical ionization is used. For normal-phase HPLC with mass spectrometric detection, an LC-MS-grade toluene with low metal and additive background is the appropriate reference material.
Store the solvent in the original amber glass bottle at 15–25 °C away from ignition sources and direct sunlight. Toluene vapor pressure at 20 °C is 28.4 hPa; containers should be opened only in a fume hood. Use PTFE-lined caps and avoid transfer through plastic lines not rated for aromatic solvents. Toluene swells natural rubber, EPDM, and silicone; use stainless steel, PTFE, PEEK, or perfluoroelastomer fluid paths. Do not use with strong oxidizers, concentrated nitric acid, or concentrated sulfuric acid. The product is not intended for food, drug, or cosmetic use. If toluene is the analyte of interest, the solvent cannot be used as the mobile phase for that determination; an alternative mobile phase such as methanol-water must be selected. The product is filtered during filling but is not sterile and should not be used as a sterile solvent.
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