HPLC (liquid chromatography) consumables sit mostly before and after the sample goes in: vials, caps, septa, tubing and guard columns, where pressure and fittings matter. GC (gas chromatography) consumables are concentrated at the inlet and both ends of the column: inlet septa, liners, O-rings and ferrules, where temperature and leaks matter. Both have “septa,” but in different places with different demands. Compare four aspects: what the consumables are, vials and septa, pressure, temperature and materials, and replacement and maintenance, then choose for your instrument. In this article, HPLC consumables means vials, caps, septa, tubing and guard columns; GC consumables means inlet septa, liners, seals, ferrules and filters; the instruments themselves, the columns themselves and reagents are outside its scope. It is divided into 4 comparisons:
- Comparison 1 | What the consumables are: what each instrument replaces.
- Comparison 2 | Vials and septa: how caps, septa and inlet septa differ.
- Comparison 3 | Pressure, temperature and materials: LC looks at pressure rating, GC at temperature.
- Comparison 4 | Replacement and maintenance: what to replace first in which situation.
This article starts from the point where you already know whether the instrument is LC or GC and want to know how the consumables divide; each source and its basis are in the Notes at the end. For choosing vials, see “How to Choose HPLC Sample Vials”; for choosing GC consumables, see “How to Choose Gas Chromatograph Consumables.” This describes the general case; individual cases still need their own assessment.
Figure 1. Four comparisons of HPLC and GC consumables (illustration, not to scale). ① What they are: HPLC, caps, septa, tubing and guard columns; GC, inlet septa, liners and ferrules. ② Vials and septa: HPLC, screw or snap caps, samples mostly aqueous; GC, mostly crimp vials, samples more volatile. ③ Pressure, temperature and materials: HPLC, tubing pressure rating and matching fittings; GC, septum and ferrule temperature grades. ④ When to replace: HPLC, pressure rise or leaks, guard column condition; GC, rising baseline or gas leaks, check the inlet first.
Comparison 1 | What the consumables are: LC before and after the sample, GC at the inlet and column ends
How to look at it:
- First write down: whether the instrument is LC or GC, and which position’s consumable is missing.
- LC commonly replaces vials, caps, septa, the tubing connecting the modules, and guard columns.
- GC commonly replaces inlet septa, liners, O-rings, inlet seals and the ferrules used at column connections.
What public sources say: an instrument maker’s selection page (date uncertain; maker’s statement) says vials include crimp, screw, snap and headspace types, commonly made of borosilicate glass; GC usually uses crimp vials, and LC commonly uses screw or snap vials. An industry magazine article on inlet maintenance (May 2018; author’s affiliation not stated) lists septa, liners, O-rings and inlet seals as consumables. A chromatography products maker’s technical note (about August 2012, date inferred from the document number; maker’s statement) says ferrules keep the connection between the column and the inlet or detector leak-tight and hold the column at the correct depth; leaks let air and water in and damage the stationary phase. The same maker’s LC troubleshooting guide (date uncertain; maker’s statement) says leaking tubing and fittings should be replaced, blocked tubing makes pressure high, and a blocked or contaminated guard column should be replaced (Notes, Table 1).
Comparison 2 | Vials and septa: the consumables the two share
How to look at it:
- First write down: whether the sample is aqueous or volatile, how long it sits in the tray, and how many times each vial is pierced.
- LC samples are mostly aqueous, with lower sealing demands; GC samples are often more volatile and may build pressure in the vial, so sealing matters more.
- The cap septum’s material, thickness and whether it is pre-slit must match the cap.
- A GC inlet septum is a different item: it is pierced repeatedly by the needle in a hot inlet, so look at its temperature grade and coring.
What public sources say: the maker’s selection page above says common septa are mostly two-layer PTFE and silicone; a septum that is too thick stops the cap seating properly and affects the seal; pre-slit septa let the needle enter more easily; and temperature ranges differ by material, for example about −40 to 200°C for PTFE and silicone, and just about 90°C for red rubber PTFE. A maker’s application note (March 2015; maker’s statement) tested 6 types of caps, piercing each vial 8 times, once every 8 hours: with a fixed-loop injector, the peak area of the volatile marker fell by 48% to 68%, and none of the caps prevented significant loss; on a model using a different injection needle, the loss was 26% to 36%; in that test, the note recommends replacing the cap as soon as possible after piercing; the note measured concentration change from evaporation, not leakage itself. The magazine article above says inlet septa must be the right size, quality and temperature grade, especially when the inlet is above 350°C; splitting or coring can cause leaks, inaccurate quantitation and retention time shifts. Another maker’s septum note (page dated 2017; maker’s statement) says coring can result from repeated piercing, a damaged needle or a mismatched needle tip style, and causes leaks and other problems; it also says septum bleed can raise the baseline and add extra peaks; softer septa core less easily but usually have a lower temperature limit; and some septa need conditioning before use (Notes, Table 2).
Comparison 3 | Pressure, temperature and materials: LC looks at pressure, GC at temperature
How to look at it:
- First write down: the LC system’s pressure limit and solvents; the GC inlet and oven temperature limits, and whether the detector is a mass spectrometer.
- For LC tubing, look at the material (stainless steel or PEEK) and the pressure the fittings can take.
- For GC septa, ferrules and seals, look at the temperature grade.
- When GC is coupled to MS, confirm the material of the ferrules at the column connection separately.
What public sources say: an LC fittings seller’s article (published 2012, updated 2026; seller’s statement) says PEEK fittings can go to about 5,000 psi in most LC work, and beyond that may deform, leak or come off suddenly; stainless steel tubing is generally rated higher than the fittings, so the fittings set the safe limit; and stainless steel fittings should not be used on PEEK tubing. Another article from the same seller (published 2023) says PEEK nuts on stainless steel tubing usually slip or blow off at about 5,000 to 6,000 psi, depending on tightening force, surfaces and alignment. For septum temperature ranges, see Comparison 2. The 2012 technical note above says all-graphite ferrules are the standard for most inlets and detectors, are porous to oxygen, are not used at MS interfaces, and can be reused if not crushed; blended ferrules of about 15% graphite and 85% another material are the standard for GC-MS, cannot be reused, shrink slightly after heating and need retightening, and may crack if over-tightened; the note gives no temperature limit figure for any ferrule (Notes, Table 3).
Comparison 4 | Replacement and maintenance: what to replace first in which situation
How to look at it:
- First write down: the current symptom (pressure rise, leaks, extra peaks, poorer peak shape) and when consumables were last replaced.
- For LC, check pressure and whether fittings leak first, then the guard column.
- For GC, check the inlet first: septum, liner, O-ring.
- Ask under what conditions each source’s “replace every so many injections” applies.
What public sources say: the troubleshooting guide above says a guard column should be replaced when blocked (high pressure) or contaminated (baseline fluctuation, extra peaks). A chromatography products maker’s article (July 2024; seller’s statement) says to replace the guard column when backpressure rises by about 10% to 15% or the sample changes, and also says to replace it every 200 to 500 injections (depending on injection volume and sample purity); the article also says column life is inversely proportional to injection volume, with the example of about 5,000 injections at 10 µL and about 500 at 100 µL (this refers to the column, not the guard column). The magazine article above says to replace inlet septa at the start of each large batch of analyses; to replace liners according to the application and how clean the samples are, without giving an injection count; to consider replacing the O-ring each time the liner is replaced; and that relying on yearly or less frequent preventive maintenance alone for inlet seals is not enough (the source’s wording of the interval is unclear). The septum note above says septa should be replaced regularly, without giving an interval. None of these sources gives a figure for how many piercings before a cap septum should be replaced (Notes, Table 4).
Comparison table: the four aspects at a glance
| Item | HPLC consumables | GC consumables |
|---|---|---|
| Common consumables | Vials, caps, septa, tubing, guard columns | Inlet septa, liners, O-rings, seals, ferrules, filters |
| Vials | Mostly screw or snap caps; samples mostly aqueous | Mostly crimp vials; samples often more volatile (maker’s statement) |
| Septa | On the cap, pierced by the injection needle | One type on caps and another at the inlet; the inlet type depends on temperature and coring |
| Pressure and temperature | Pressure rating of tubing and fittings | Temperature grade of septa and ferrules |
| When to replace | Look at pressure, leaks and the guard column | Look at septa, liners and seals; sources give different conditions |
Sources: Notes, Tables 1 to 4 (Sources 1 to 8). These are the sources’ statements; the sources do not all agree, and these are not selection thresholds.
How to choose: when to look at LC consumables first, and when GC first
Based on public sources, the two can be divided this way:
- LC: when pressure rises, there are leaks or peak shape worsens, look first at tubing, fittings and the guard column (Sources 4, 8); vial septa must match the cap (Source 1); in Source 5’s test, the volatile marker’s concentration fell after piercing (Source 5).
- GC: when the baseline rises, extra peaks appear, gas leaks or retention times shift, look first at the inlet septum, liner and O-ring (Sources 2, 6); when coupled to MS, confirm the material of the column-connection ferrules separately (Source 3).
- Both: the material, thickness and temperature range of cap septa (Source 1).
- Near the boundary: the sources give no line for “replace after so many piercings or injections,” and the guard column’s “10% to 15% or 200 to 500 injections” and the septum’s “start of each batch” rest on different conditions; go by your instrument, samples and injection volume (Sources 2, 8).
These are statements from public sources, not conclusions about your instrument; which to replace still depends on your instrument, samples and symptoms.
How JIAHON can help: the items below use the product names and page text alone, without quoting models or specification figures; please contact us for sizes, materials, temperatures and pressures. On the GC side, several pages cover multiple kinds of consumables and 2 pages share the same name, so each page is listed separately.
HPLC side:
- 2 mL amber screw-cap sample vials, HPLC: the product name reads 2 mL amber screw-cap sample vials HPLC, with a brand listed; the page says caps and septa are sold separately; please contact us.
- HPLC sample vial septa, PTFE/silicone composite: the product name reads HPLC sample vial septa, with a brand and model listed; please contact us for the temperature range.
- HPLC capillary tubing (white/PEEK): the product name reads HPLC capillary tubing, with a brand and model listed; please contact us for material and usable pressure.
GC side:
- Gas chromatograph accessories: the product name reads gas chromatograph accessories, with a brand listed; the page lists five items including flame detector ferrules, inlet septa, ferrules and sealing rings; please contact us.
- Gas chromatograph accessories series: the product name reads gas chromatograph accessories series, with a brand listed; the page mixes liners, columns, syringes and vacuum pump oil; please contact us.
- Gas chromatograph accessories series: a different page with the same product name and another brand listed; the page is mostly valves, fittings and hoses for sampling lines, plus filters and leak detection fluid, not all consumables; please contact us.
- Gas chromatograph sampling system filter series: the product name reads gas chromatograph sampling system filter series, with a brand listed; the page has filter housings and replacement kits; please contact us for materials.
- GC sampling filter elements: the product name reads GC sampling filter elements, with a brand listed; the page lists three pore sizes; confirm which element fits which filter housing first; please contact us.
When you need to match a type, please prepare six items first: whether the instrument is LC or GC, and its maker and model; which position’s consumable is missing; thread, tube diameter or size; sample properties and injection volume; pressure or temperature limit; and the model you use now and the symptom you see. You are welcome to contact JIAHON.
Notes: sources and exceptions
The following is for readers who want to check; you can follow the steps above without it. Where your instrument maker’s written specifications, site rules or sample conditions differ from this article, follow them.
Sources for each comparison
| Source | Where used and origin |
|---|---|
| Source 1 | Comparisons 1, 2: vial types, sealing demands, septum materials and temperature ranges. Origin: an instrument maker’s vial selection page (date uncertain; maker’s statement; does not distinguish HPLC and UHPLC) |
| Source 2 | Comparisons 1, 2, 4: inlet consumables, inlet septa, replacement timing. Origin: a chromatography trade magazine’s inlet maintenance article (1 May 2018; author’s affiliation not stated; the page metadata carries a 2026 timestamp, likely the date the page was republished) |
| Source 3 | Comparisons 1, 3: ferrule function, materials and use. Origin: a chromatography products maker’s technical note (about August 2012, date inferred from the document number; maker’s statement) |
| Source 4 | Comparisons 1, 4: LC leaks, blocked tubing and guard columns. Origin: the same maker’s LC troubleshooting guide (date uncertain, content taken from a 2014 to 2015 catalog; maker’s statement) |
| Source 5 | Comparison 2: concentration change after piercing cap septa. Origin: another instrument maker’s application note (March 2015; maker’s statement; describes the test design) |
| Source 6 | Comparisons 2, 4: inlet septum coring, septum bleed and replacement. Origin: a chromatography consumables maker’s septum note (page dated 2017; maker’s statement) |
| Source 7 | Comparison 3: PEEK fitting pressure ratings. Origin: an LC fittings seller’s knowledge article and another from the same seller (first published 2012, second published 2023, both updated in 2026; seller’s statement) |
| Source 8 | Comparison 4: guard column replacement conditions and life examples. Origin: a reagent and chromatography products maker’s technical article (July 2024; seller’s statement) |
| JIAHON material | “How JIAHON can help.” Origin: JIAHON product pages (10 pages) |
Table 1 | What the consumables are
| Item | Content |
|---|---|
| Vial types | Crimp, screw, snap, headspace and others; commonly borosilicate glass; GC usually uses crimp vials, LC commonly screw and snap vials (Source 1, maker’s selection page) |
| Inlet consumables | Septa, liners, O-rings (where fitted), inlet seals and washers (Source 2, trade magazine) |
| Ferrules | Keep the column-to-inlet or detector connection leak-tight and hold the column at the correct depth; leaks let air and water in and damage the stationary phase (Source 3, maker’s technical note) |
| LC replacement cases | Leaking tubing and fittings should be replaced; blocked tubing makes pressure high; blocked or contaminated guard columns should be replaced (Source 4, maker’s troubleshooting guide) |
Sources: 1, 2, 3, 4
Table 2 | Vials and septa
| Item | Content |
|---|---|
| Sealing demands | LC samples are usually aqueous, so sealing matters less; GC samples are more volatile, may have internal pressure, and sealing is critical (Source 1, maker’s selection page) |
| Septum material and thickness | Common septa are mostly two-layer PTFE plus silicone; too thick stops the cap seating and affects the seal; pre-slit lets the needle enter more easily (Source 1, maker’s selection page) |
| Temperature range | PTFE/silicone about −40 to 200°C; red rubber PTFE about −40 to 90°C; a range for high-performance septa is also given (the last item is not quoted in the main text) (Source 1, maker’s selection page) |
| Concentration change after piercing | 6 PTFE/silicone caps, each vial pierced 8 times at 8-hour intervals, measured to 56 hours; with a fixed-loop injector, volatile marker peak area fell 48% to 68%; on a model with a different injection needle, loss was 26% to 36%; in that test the volatile marker’s concentration fell after piercing, and the note recommends replacing caps as soon as possible; it measured concentration change from evaporation, not leakage itself (Source 5, maker’s application note) |
| Inlet septa | Choose the right size, quality and temperature grade, especially when the inlet is above 350°C; splitting or coring can cause leaks, inaccurate quantitation and retention time shifts (Source 2, trade magazine) |
| Coring and septum bleed | Repeated piercing, a damaged needle or a mismatched needle tip style cause coring, which causes leaks and other problems; septum bleed can raise the baseline and add extra peaks (written separately; the source does not attribute baseline rise to coring); softer septa core less easily but usually have lower temperature limits; some septa need conditioning before use (temperature limits for two septa are also listed, not quoted in the main text) (Source 6, maker’s septum note) |
Sources: 1, 2, 5, 6
Table 3 | Pressure, temperature and materials
| Item | Content |
|---|---|
| PEEK fitting pressure | Most HPLC work up to about 5,000 psi; beyond that they may creep, deform, leak or come off suddenly; stainless steel tubing is generally rated higher than the fittings, so the fittings set the safe limit; stainless steel fittings must not be used on PEEK tubing (Source 7, fittings seller) |
| PEEK nuts on stainless steel tubing | Usually slip or blow off at about 5,000 to 6,000 psi, depending on tightening force, surfaces and alignment (another article from the same seller, published 2023) (Source 7, fittings seller) |
| All-graphite ferrules | The standard for most inlets and detectors; porous to oxygen, not used at MS interfaces; reusable if not crushed (softer and may shed graphite particles, not quoted in the main text) (Source 3, maker’s technical note) |
| Graphite blended ferrules | About 15% graphite and 85% another material (trade name not given); the standard for GC-MS; not reusable; shrink slightly after heating and need retightening; may crack if over-tightened (Source 3, maker’s technical note) |
| Other ferrules | Metal ferrules, finger-tight fittings and others are also covered (not quoted in the main text); no temperature limit is given for any ferrule (Source 3, maker’s technical note) |
Sources: 3, 7
Table 4 | Replacement and maintenance
| Item | Content |
|---|---|
| Guard column (troubleshooting guide) | Replace when blocked (high pressure) or contaminated (baseline fluctuation, extra peaks); an aging guard column may also broaden, split or tail peaks (Source 4, maker’s troubleshooting guide) |
| Guard column (technical article) | Replace when backpressure rises about 10% to 15% or the sample changes; also says every 200 to 500 injections (depending on injection volume and sample purity); another passage says column life is inversely proportional to injection volume, with the example of about 5,000 injections at 10 µL and about 500 at 100 µL (this refers to the column, not the guard column) (Source 8, maker’s technical article) |
| Inlet septa | Replace at the start of each large analysis campaign; over-tightening may split the septum (Source 2, trade magazine); another source says replace regularly, without an interval (Source 6, maker’s septum note) |
| Liners | Replace according to the application and how clean the samples are; no injection count given; visual inspection alone is unreliable (Source 2, trade magazine) |
| O-rings and seals | Consider replacing the O-ring each time the liner is replaced; replacing seals just at yearly or less frequent preventive maintenance is not enough (the source’s wording of the interval is unclear) (Source 2, trade magazine) |
| Septum piercing count | None of these sources gives a figure |
Sources: 2, 4, 6, 8
This describes the general case; individual cases still need their own assessment.
Exceptions and limits
What was and was not seen: this article draws on 1 instrument maker’s vial selection page (date uncertain, maker’s statement), 1 chromatography trade magazine article on inlet maintenance (May 2018, author’s affiliation not stated), 1 chromatography products maker’s technical note (about August 2012, date inferred from the document number, maker’s statement), 1 LC troubleshooting guide from the same maker (date uncertain, content from a 2014 to 2015 catalog, maker’s statement), 1 application note from another instrument maker (March 2015, maker’s statement), 1 chromatography consumables maker’s septum note (page dated 2017, maker’s statement), 2 knowledge articles from the same LC fittings seller (first published 2012, second 2023, both updated in 2026, seller’s statement), and 1 reagent and chromatography products maker’s technical article (July 2024, seller’s statement). Of the 8 numbered sources, 7 were written by makers or sellers and 1 is a trade magazine article; none includes full test conditions (just Source 5 describes its test design), and no standard text was read. No university lecture notes or neutral organization documents were found; no figure was found for how many piercings before an inlet septum or a vial septum should be replaced (Sources 2 and 6 give no interval, and Source 5 says to replace caps soon after piercing within its own test); Source 3 gives no temperature limit for any ferrule; and Source 1 does not distinguish HPLC and UHPLC.
Figures are examples: each figure quoted in the main text is marked with its conditions and source (Source 1’s temperature ranges, Source 2’s 350°C, Source 5’s 48% to 68% and 26% to 36%, Source 7’s 5,000 and 6,000 psi, Source 8’s 10% to 15% and 200 to 500 injections); Source 8’s “about 5,000 injections at 10 µL and about 500 at 100 µL” refers to column life, not guard columns, and is that article’s own example, not a general rule; Source 5’s figures are results for that experiment’s 6 caps and 2 injectors and cannot be extended to other caps and instruments. None of these are selection thresholds.
Sources disagree: on guard column replacement, Source 4 says “replace when blocked or contaminated,” and Source 8 says “when backpressure rises about 10% to 15%, the sample changes, or every 200 to 500 injections”; both are listed, and the main text does not decide for you. Source 7’s pressure figures are general statements about PEEK fittings; the specifics depend on fitting type, tubing and the instrument’s rated pressure; this is a reminder from this article, not the source’s words. Source 3 says the blended ferrule contains 85% of one material, which is that material’s trade name; the main text and Notes write “another material” instead.
Single sources: vial and cap types, the usual LC/GC differences, and septum materials and temperatures (Source 1); each inlet maintenance item (Source 2); ferrule materials and use (Source 3); concentration change after piercing cap septa (Source 5); the effects of coring and septum bleed (Source 6); PEEK fitting pressure (Source 7); guard column replacement conditions and life examples (Source 8).
Sources with a stake: Sources 1, 3, 4, 5 and 6 are makers, Sources 7 and 8 are sellers’ or makers’ technical articles, and Source 2’s author’s affiliation is not stated; none is a standard text or a third-party test report, so their statements can serve as illustrative examples alone.
Units: units are given as the sources give them.
This article’s own compilation: the main text uses no “compiled by this article” marker, and each statement can be traced to the sources above. The “How to choose” section sorts the sources’ statements into three cases, “what to check first for LC,” “what to check first for GC” and “check for both”; this is a compilation, not the sources’ own sentences, and it states that the sources give no boundary.
Scope: in this article, HPLC consumables means vials, caps, septa, tubing and guard columns, and GC consumables means inlet septa, liners, seals, ferrules and filters; the instruments themselves, the columns themselves and reagents are outside its scope; it does not cover model cross-references, prices or lead times; it does not say anything “meets regulations” or “is safe this way,” and for anything involving pressure, high temperature and gases, follow the instrument maker’s specifications and site rules.
Equipment and products: “How JIAHON can help” uses the product names and page text from the product pages as read on 13 October 2026, without quoting models or specification figures; for sizes, materials, temperatures and pressures, please contact us, and the details confirmed by our sales team apply.
This article is a summary of the general case, not a restatement of any standard, not an endorsement of any supplier, equipment maker or service provider, and not a promise about your instrument or site. Follow your instrument maker’s written specifications, site rules and safety rules, and your own validation; this describes the general case, and individual cases still need their own assessment.
Related reading
- “How to Choose HPLC Sample Vials” (/en/hplc-sample-vial-selection-guide/, EN591)
- “How to Choose Gas Chromatograph Consumables”