The increasing consumption of processed foods demands the usage of chemical preservatives to ensure freshness and extended shelf life. For this purpose, sodium sulfite and its derivatives have been widely used in a variety of food products to inhibit microbial spoilage and for mitigating oxidative decay. However, the excessive consumption of sulfite may cause health problems, thus requiring rapid and accurate analytical methods for the rapid identification of threshold levels. Conventionally, sulfite is volatilized from food samples by acidification followed by trapping of the gaseous SO₂ and determination using a suitable analytical technique. Herein, we propose a yet unprecedented reagent-less approach via direct absorbance measurements of gaseous SO₂ at 280 nm after sample acidification. The detection system combines a deep-UV LED and a SiC photodiode with a substrate-integrated hollow waveguide (iHWG) gas cell. Absorbance measurements were performed using a log-ratio amplifier circuitry, resulting in noise levels <0.7 mAU. This innovative concept enabled the determination of sulfite in beverages in the range of 25–1000 mg L⁻¹ with suitable linearity (r² > 0.99) and an analysis time <30 s. The limit of detection (LOD) was calculated at 14.3 mg L⁻¹ (3σ) with an iHWG providing an optical path length of 75 mm. As a proof of concept, this innovative analytical platform was employed for sulfite quantification in concentrated grape juice, coconut water and beer, with suitable accuracy in terms of recovery (83–117%) and favorable comparison with the official Monier-Williams method. Given the inherent modularity and adaptability of the device concept, we anticipate the application of the proposed analytical platform for the in-situ studies addressing sulfite and other volatilized preservatives in a wide variety of food products with tailorable detectability.

加工食品消费量的增加要求使用化学防腐剂来确保新鲜度和延长保质期。为此，亚硫酸钠及其衍生物已广泛用于各种食品中，以抑制微生物腐败和减轻氧化腐烂。然而，亚硫酸盐的过量消耗可能会导致健康问题，因此需要快速准确的分析方法来快速识别阈值水平。通常，亚硫酸盐通过酸化从食品样品中挥发，然后捕获气态 SO ₂并使用合适的分析技术进行测定。在此，我们通过直接测量气态 SO _{2的吸光度提出了一种前所未有的无试剂方法}样品酸化后在 280 nm 处。该检测系统将深紫外 LED 和 SiC 光电二极管与基板集成中空波导 (iHWG) 气室相结合。使用对数比放大器电路进行吸光度测量，导致噪声水平 <0.7 mAU。这一创新概念能够测定饮料中 25–1000 mg L ⁻¹范围内的亚硫酸盐，并具有合适的线性 (r ²  > 0.99) 和分析时间 <30 秒。检测限 (LOD) 计算为 14.3 mg L ^-1(3σ) 与 iHWG 提供 75 mm 的光程长度。作为概念证明，该创新分析平台被用于浓缩葡萄汁、椰子水和啤酒中的亚硫酸盐定量，在回收率方面具有合适的准确度 (83–117%)，并且与官方的 Monier-Williams 方法具有良好的对比。鉴于设备概念固有的模块化和适应性，我们预计所提出的分析平台将应​​用于原位研究，以解决具有可定制检测能力的各种食品中的亚硫酸盐和其他挥发性防腐剂。