Testing for 2,3-Pentanedione: The "Other" Diacetyl and What Every Flavor Manufacturer Must Verify
作者： 翠盖调味研发团队出版：广东独特风味有限公司最后更新： 九月 11，2026WhatsApp与Telegram： +86 189 2926 7983电子邮件：info@cuiguai.com2,3-Pentanedione — also known as acetylpropionyl, CAS number 600-14-6 — is the flavoring diketone that quietly replaced diacetyl across much of the e-liquid and food flavor industry, and it is the compound most likely to trip up a "diacetyl-free" claim. When brands and importers demand diketone testing, they usually ask for diacetyl and stop there. That is a gap. 2,3-Pentanedione shares diacetyl's buttery chemistry and, according to occupational health agencies, much of its inhalation hazard profile, which is why a defensible quality program must measure it explicitly.This guide explains what 2,3-pentanedione is, how regulators and occupational health bodies treat it, which analytical methods actually detect it, and what a defensible certificate of analysis (CoA) should contain. It is written for e-liquid brand owners, importers, and technical buyers who source flavor concentrates and need laboratory-grade confidence in what their supplier ships. The short version of our advice: never accept a diketone claim without a number, never accept a number without a method, and always insist that 2,3-pentanedione is measured in the same run as diacetyl.GC-MS 是十亿分之一级 2,3-戊二酮定量的主力仪器
电子液体和调味剂浓缩物中 2,3-戊二酮的 GC-MS 测试
1. 什么是 2,3-戊二酮？
2,3-Pentanedione (IUPAC name pentane-2,3-dione; molecular formula C5H8O2; molar mass 100.12 g/mol) is a vicinal diketone — two adjacent ketone groups on a five-carbon chain. It is a clear to pale-yellow liquid with a buttery, caramel-like odor, and its flavor character is described as sweet, buttery, creamy, cheesy, and slightly toasted, with a rich baked-goods nuance. In food it is used to flavor cookies, coffee, cereal, and chocolate; in vaping it appears in sweet and creamy e-liquid profiles. The US National Institutes of Health's PubChem record for CAS 600-14-6 lists it under the synonym acetylpropionyl and identifies it as FEMA No. 2841, the number assigned to it in the Flavor and Extract Manufacturers Association's GRAS assessment program.
The authoritative occupational reference is NIOSH's Criteria for a Recommended Standard: Occupational Exposure to Diacetyl and 2,3-Pentanedione (DHHS (NIOSH) Publication No. 2016-111). The document reviews the animal and worker evidence for both compounds and proposes recommended exposure limits (RELs) at low parts-per-billion concentrations for 8-hour time-weighted averages, together with short-term limits, plus a hierarchy of controls from substitution through ventilation to respiratory protection. In practical terms, NIOSH is saying the industry should treat 2,3-pentanedione as seriously as diacetyl wherever concentrates are handled or heated.
2.2 这两种化合物都有职业空气测试方法
For workplace air monitoring, NIOSH and OSHA have published validated sampling and analytical methods. NIOSH's Manual of Analytical Methods (NMAM) Method 2557 covers diacetyl by gas chromatography with flame ionization detection (GC-FID), using carbon molecular sieve sorbent tubes, desorption in acetone/methanol, and a wax-phase capillary column. The method is explicitly historical — NIOSH found it underestimates diacetyl in humid air and evaluated derivatization with o-phenylenediamine as an alternative — but its documentation is valuable because it confirms the OSHA method landscape: OSHA methods 1012 and 1013 for diacetyl, and OSHA 1016 specifically for 2,3-pentanedione. These methods are for occupational exposure assessment, not finished-product testing, but they define the analytical chemistry a flavor lab should be able to replicate.
2.3 食品授权不是吸入授权
A common misconception is that GRAS or EU-listed status settles the safety question for vaping. It does not. The FEMA GRAS program (which assigned 2,3-pentanedione its number 2841) evaluates flavoring substances for use in food, not for inhalation. Similarly, the European Union's flavouring framework — Regulation (EC) No 1334/2008, whose Union list of authorised flavouring substances was established by Commission Regulation (EU) No 872/2012 — governs flavouring use in foodstuffs. Neither regime assesses chronic inhalation of heated, vaporized flavoring chemicals. In the US, e-liquids fall under the FDA's tobacco product jurisdiction, and the National Academies of Sciences, Engineering, and Medicine's 2018 report on the public health consequences of e-cigarettes reviewed diketones in its toxicology chapter, flagging diacetyl and 2,3-pentanedione among the constituents of concern. The regulatory conclusion for manufacturers is simple: food authorization is necessary due diligence, but it is not a substitute for inhalation-relevant toxicology or finished-product testing.
Regulators and retailers are converging on a simple expectation: the manufacturer of a flavored e-liquid should be able to state, in parts per billion, what its diketone levels are and which tests support that statement. In jurisdictions where flavor or ingredient restrictions apply to specific compounds, the declared composition and its supporting analytical data become part of a registration, notification, or premarket file, and gaps in the data trail can stall market entry. There is also a commercial use: a quantified low-diketone position is a genuine differentiator in a category where bare "diacetyl-free" claims are treated with justified skepticism. Distributors increasingly request the same three numbers — diacetyl, 2,3-pentanedione, acetoin — in every tender, so having them on file is becoming table stakes for doing business.
There are two materially different questions. Liquid testing answers "what is in the bottle": the concentrate or finished liquid is diluted in solvent (or extracted by solid-phase microextraction) and injected directly. Aerosol testing answers "what reaches the user": a vaping machine draws puffs under defined regimes and the generated aerosol is collected on sorbent tubes, filters, or impingers, then desorbed and analyzed. The distinction matters because the two numbers can diverge substantially — some flavor compounds transfer to aerosol inefficiently, while others concentrate. The most widely cited market survey of this problem is Farsalinos and colleagues' 2015 study in Nicotine & Tobacco Research, which tested 159 sweet-flavored e-liquids from 36 manufacturers and retailers across six European countries and the US and found diacetyl and acetylpropionyl in a large proportion of samples, many at levels above the strictest exposure-based limits.
3.3 可靠的分析证书必须包含哪些内容
Method and instrumentation, 包括色谱柱类型、检测模式和使用的分析标准。
Detection and quantification limits, 针对实际样品基质，而不仅仅是标准溶液。
Results for all three relevant compounds, 二乙酰、2,3-戊二酮和乙偶姻 — 乙偶姻是因为它是常见的低风险解决方法，值得拥有自己的数据点。
Calibration information, 例如线性范围、R2 和标准品的可追溯性。
Sample preparation details, 包括稀释因子以及是否测试液体或气溶胶。
Batch identity and traceability, 加上签名、日期和实验室的认证参考信息。
3.4 选择实验室：要寻找什么
Not every analytical lab can quantify diketones reliably in a concentrated flavor matrix, so supplier selection deserves the same rigor as the testing itself. The practical shopping list: an ISO 17025 accreditation that actually covers the method in question; demonstrated experience with flavor concentrates and e-liquid matrices, which are demanding because of high sweetener loads, viscous carriers, and reactive diketones that degrade in hot inlets; published detection limits in the parts-per-billion range for diacetyl, 2,3-pentanedione, and acetoin; a willingness to share method details such as column phase, injection temperature, and internal standard; and batch-level reporting with fast turnaround. A lab that quotes "diacetyl only" is itself a warning sign: the same run that quantifies diacetyl costs almost nothing extra to extend to 2,3-pentanedione and acetoin, and the three numbers together are what a credible CoA needs.经过认证的参考标准将校准曲线固定在每个报告结果的后面。
2,3-戊二酮定量的认证分析标准品
四、围绕二酮问题制定
4.1 The flavorist's toolkit
Creamy, buttery, and custard-like notes can be rebuilt without high-risk diketones, but not by simply deleting an ingredient — the formula has to be re-architected. Practical levers include acetoin (itself under occupational scrutiny and therefore subject to its own reporting), butyric acid and its esters at sub-taste-threshold doses, gamma- and delta-lactones that deliver dairy-like mouthfeel, vanilla and maltol systems that mask the loss of buttery sweetness, and non-diketone cream modifiers that add viscosity and roundness in the vapor. Each substitution changes the flavor's heat stability, oxidation behavior, and interaction with nicotine, which is why reformulation should be paired with stability and aerosol-transfer testing rather than a straight swap.这些替代品背后的安全性逻辑——乙偶姻和乙酰丙酰的实际作用、它们如何比较以及替代品的实际效果如何——在我们的技术简报中进行了介绍 managing diacetyl substitutes and the safety profile of acetoin and acetyl propionyl。它是最接近决策树的东西，用于选择哪个 buttery-note 构建器属于哪个产品。
