专业法医检测试剂A——乙醇挥发性成分气相接触显色·快速半定量筛查化学试剂（刑事技术酒精残留物现场检测/法医实验室物证化学初筛专用试剂）

 

专业法医检测试剂A——乙醇挥发性成分气相接触显色·快速半定量筛查化学试剂（刑事技术酒精残留物现场检测/法医实验室物证化学初筛专用试剂）

〖重要合规前置声明〗 本产品为刑事技术法医检验专用化学试剂，仅面向具备法定鉴定资质与刑事技术检验许可的各级公安机关刑事技术部门、人民检察院技术部门、司法鉴定机构及授权刑事技术实验室定向供应，严禁向任何个人、无资质企业及非授权单位销售或提供。本试剂的使用与管理，必须严格遵守《中华人民共和国刑事诉讼法》《司法鉴定程序通则》《公安机关刑事案件现场勘验检查规则》及国家关于危险化学品管理、实验室安全的有关法律法规与行业技术标准，必须由经过专业培训、取得相应法医检验或刑事技术岗位资质的人员规范操作，严禁无资质单位和个人违规获取、使用本试剂，严禁将本试剂的检测结果直接作为法定鉴定依据，阳性结果须经实验室仪器方法确证，严禁在无防护条件下直接接触试剂液体，严禁将本试剂用于法定物证检验之外的任何用途。

产品概述

专业法医检测试剂A——乙醇挥发性成分气相接触显色·快速半定量筛查化学试剂（亦称酒精成分检测试剂、乙醇残留物化学筛查试剂）是一款专为法医科学及刑事技术领域设计的酒精成分定向检测化学试剂，属于公安刑事技术现场勘查与法医实验室物证化学初筛领域的专用检测耗材。该产品基于特定的显色化学反应原理，专门用于对可疑载体表面吸附或残留的乙醇（酒精）成分进行快速、直观的初步筛查与半定量分析，完美适配交通事故中肇事车辆方向盘与座椅的酒精残留检测、火灾与爆炸案现场酒精类助燃剂泼洒范围判断、刑事侦查中可疑液体及衣物的酒精成分排查以及检察院技术检验中送检物证的化学初筛等多种法医物证检验场景。试剂采用非接触式气相检测设计，利用乙醇自身的高挥发性特性，只需将经试剂浸润的检测滤纸悬置于被检样品上方，即可在数分钟内通过滤纸上生成的特征色斑对酒精成分进行定性及半定量判读，从根本上解决了传统液体试剂直接滴加于检材表面可能导致的物证污染、稀释或破坏问题，同时避免了因检材珍贵微量而无法取样检测的实战痛点，能够为法医鉴定人及现场勘查人员提供“无需接触检材、操作极简、反应迅速、结果直观”的酒精成分现场化学筛查能力，是交通事故调查、火灾物证检验及各类涉及酒精残留的刑事案件物证初筛的重要法医检测工具。

技术原理

该试剂基于气相扩散接触与特异性化学显色的双重原理工作。其检测机制的核心在于不依赖液体试剂与检材表面的直接物理接触，而是利用乙醇在常温下具有较高饱和蒸气压、极易从吸附载体表面挥发的物理化学特性，构建了一个“气相待测物—固相试剂载体”的非接触式反应体系。具体工作流程为：操作者将适量试剂滴加于检测滤纸上，使试剂组分均匀负载于滤纸纤维载体内，随后将该滤纸悬置于被检样品表面上方并保持一定微小间隙。样品中若含有残留乙醇，其挥发出的乙醇分子将通过气相传质扩散至滤纸表面，与试剂中的特定显色活性组分发生不可逆的化学反应，生成具有特定可见光谱吸收的显色化合物，在滤纸上形成肉眼清晰可辨的特征色斑。

该反应在室温条件下通常在数分钟内即可完成。滤纸上色斑的三项核心特征——颜色、扩散范围大小以及从无色到完全显色所需的时间——均与样品中乙醇的挥发速率及局部气相浓度呈正相关关系，而后者又直接取决于样品吸附的乙醇总量及浓度水平。操作者通过将生成的色斑与标准比色卡或已知浓度的对照样本进行目视比较，即可对样品中挥发出的酒精含量进行初步的半定量评估，将其判定为微量、显著或高浓度等粗略浓度等级。试剂采用化学性质稳定的配方，以50毫升深色试剂瓶封装，避免光照对活性组分的光化学降解，确保在规定的遮光、阴凉储存条件下长期保持反应活性与检测可靠性。整个检测流程为一次性、不可逆的化学反应，反应后生成的显色痕迹可在滤纸上自然固定并长期保存，作为原始检测记录的技术附件归档，满足法医物证初筛检验中对原始记录完整性与可追溯性的基本要求。

核心功能与合规实战价值

非接触式气相检测机制，从源头规避物证污染与完整性风险
试剂专门针对气态乙醇设计反应路径，操作时检测滤纸与检材表面之间无任何液体接触或直接摩擦。该非接触工作模式从流程设计上完全杜绝了传统液体试剂直接滴加于可疑斑迹后因浸润扩散导致原始物证形态改变、化学成分相互污染或稀释等破坏检材完整性的风险——尤其适用于不宜直接滴加液体的珍贵衣物物证、文检件证及微量残渣等检材。在交通事故调查中鉴定人需对肇事车辆方向盘残留物质进行酒精筛查的场景下，采用气相检测模式可彻底避免因液体试剂浸泡而导致的皮革或塑料内饰面被化学侵蚀、影响后续物理痕迹提取（如指纹、工具痕迹）的严重后果，完美契合了法医物证检验中“先无损、后有损”的法定检验顺序原则与物证保全的强制性规范要求。

极简操作流程与数分钟即时显色，满足一线勘查现场快速筛查的时效性需求
检测操作仅需滴加试剂、悬置滤纸、观察结果三个步骤，全程所需器具仅为试剂瓶与普通检测滤纸，无需任何仪器设备、电源或加热辅助。反应在室温条件下通常在数分钟内即可完成，生成的特征色斑颜色鲜明、与白色滤纸底色之间形成高对比度，可在现场自然光或手电照明下直接目视判读。该极简操作特性使交警在事故现场勘查车内酒精痕迹、刑警在搜查现场排查可疑液体及法医检验人员在实验室对大批量检材进行预筛时均能快速完成检测，将酒精物证的初步定性窗口从传统的数日实验室气相色谱检验周期压缩至数分钟现场即时完成，为是否需要进一步送检确证及侦查方向调整提供了第一时间的化学依据。

半定量色斑判读体系，为实验室确证检验提供浓度等级的初步导向
试剂反应生成的色斑通过颜色深浅、扩散范围及显色时间三项可观测指标，可与标准比色卡或已知浓度的酒精对照样本进行比对，从而对样品中挥发出的乙醇含量作出粗略的半定量评估——通常可区分为微量、显著、高浓度等层次。这一半定量能力使得鉴定人在进行仪器确证之前，即可依据色斑强度判断检材中酒精残留的大致浓度范围，为后续选择合适的气相色谱定量方法、确定稀释倍数及优化进样体积提供了实验设计层面的重要参考，有效提升了实验室检验资源的靶向利用率，避免了盲目进样导致的色谱柱污染或重复检测。

稳定化学配方与深色避光封装，保障长期存储与按需取用的可靠性
试剂采用化学性质稳定的配方体系，灌装于50毫升深色试剂瓶中密封存储。深色瓶体有效阻挡紫外光及可见短波光对活性组分的光化学降解作用，结合阴凉、避光、密闭的推荐储存条件，保障了试剂在长期保存周期内的反应灵敏度与检测一致性。标准化的实验室瓶装规格配合旋盖密封设计，方便按需取用和余量保存，降低了大型实验室大批量库存的管理成本，同时保证了每次现场或实验室检测所使用的试剂均处于质量控制有效期内的最佳活性状态。

合规应用场景

交通事故与危险驾驶案件酒精残留快速检测场景
在涉嫌酒驾、醉驾或肇事逃逸案件调查中，交警或刑事技术人员使用本试剂对肇事车辆的方向盘、换挡杆、驾驶座安全带、车内饮品容器边缘等位置进行非接触式气相显色筛查。检测时无需用试剂直接擦拭被检部位，只需将经试剂浸润的滤纸悬置于可疑区域上方数分钟，即可通过色斑判断是否存在酒精残留，为交通事故责任认定及危险驾驶行为定性提供化学初筛依据。操作过程完全符合《道路交通安全法》及公安机关办理危险驾驶案件的相关勘查规范中对物证提取程序合法性的要求，检测记录可作为后续实验室仪器确证的参考佐证材料。

火灾与爆炸事故现场酒精类助燃剂排查场景
在火灾调查中，调查人员使用本试剂对起火点周围的地面、家具残骸、容器碎片等可疑位置进行酒精泼洒范围的初步确定。滤纸悬置于多个采样点位上方，通过比较各点位色斑强度差异，大致判断酒精类易燃液体在案发现场的泼洒路径与集中区域，为火灾原因认定和放火嫌疑排除提供直观的化学证据线索。检测过程无需对火灾残骸进行湿法提取或破坏性取样，最大限度地保全了现场的原始状态与后续理化实验室定量检验的可操作性。

刑事案件中可疑液体与浸渍物证酒精成分初步排查场景
在涉毒、涉暴等刑事案件侦查中，勘查人员对现场发现的不明液体瓶罐、浸渍可疑液体的衣物、毛巾、纸巾等物证，使用本试剂进行酒精成分快速初筛。对于不宜直接取液的密封容器内液体，将浸润试剂的滤纸悬置于瓶口上方即可以通过瓶口逸散蒸气进行检测，避免了开瓶取液对原始物证的破坏及对操作人员可能造成的化学暴露风险。初筛结果若为阳性，该检材将被优先纳入确证检验队列，有效指导了现场物证的分类提取与后续检验资源的合理分配。

检察院技术检验环节送检物证化学快速筛查场景
检察机关技术部门在受理公安机关移送审查起诉的案件过程中，对随案移送的含有可疑浸渍斑迹的衣物、擦拭棉签等物证需要进行刑事技术审查。技术检验人员使用本试剂对上述物证进行初步的酒精成分定性筛查，并将检测产生的滤纸色斑作为原始检测凭证连同操作记录一并归档，为检察官作出是否需要进行补充鉴定或进一步调查的决定提供客观的技术审查参考。筛查操作及其记录全程符合检察机关技术办案规范化建设中对检验程序客观性、可追溯性的管理要求。

核心技术参数

产品规格方面，标准包装为50毫升/瓶，采用深色试剂瓶封装，有效避光以保障试剂化学稳定性与长期存储反应活性。检测目标专一针对乙醇（酒精）挥发性成分，检测原理基于待测乙醇分子通过气相传质与固相试剂载体中活性组分发生特异性显色化学反应。操作方式采用气相接触显色模式，将试剂滴加于检测滤纸后悬置于被检样品表面上方，全程无液体直接接触检材。判读方式通过观察滤纸上生成的特征色斑颜色深浅、扩散范围及显色时间三项指标，与标准比色卡或已知浓度对照样本进行目视比较，实现定性检出与粗略半定量评估。标准配置包含专业法医检测试剂A一瓶（50毫升） 及产品使用说明书一份（含详细操作流程与结果判读指南）。

合规实战应用案例

某市发生一起车辆冲撞行人后肇事逃逸案件，交警大队于次日凌晨锁定一辆可疑轿车，但嫌疑人否认曾驾驶该车辆，称该车已多日未使用。交通勘察人员提取了方向盘皮革套表面及驾驶座安全带织物的微量擦拭样本，并使用本专业法医检测试剂A在勘查车内进行现场筛查。技术人员将试剂滴加于滤纸后，分别悬置于方向盘三九点钟位置及安全带肩部区域上方，约三分钟后方向盘处滤纸出现显著粉红色斑，安全带处滤纸呈浅色弱阳性反应。根据相同操作条件下色斑强弱对比，判定方向盘区域存在较高浓度酒精挥发残留。该初筛结果经现场笔录记载并由后续实验室气相色谱确证后，成为判断该车辆在案发当晚曾被驾驶使用的重要间接证据，为突破嫌疑人不在场辩解提供了关键的技术支撑。

某省刑事科学技术研究所受理一起火灾致人死亡案件的物证检验委托，需对现场提取的多个烧损容器碎片及浸渍有疑似可燃液体的木地板残块进行酒精类助燃剂筛查。法医检验人员统一使用本试剂，对各检材采样点逐次进行气相显色检测。通过在相同检测条件下比较各点位滤纸色斑的显色时间与颜色深度，检验人员发现起火点卧室床铺周围几块地板残片对应的滤纸色斑颜色最深、显色时间最短，而客厅区域的检材色斑反应微弱或呈阴性。据此初步判断酒精类易燃液体主要泼洒于卧室内，且泼洒范围相对集中。该化学初筛结论为火灾调查组正确认定起火点位置、分析火灾蔓延方向及判断案发性质提供了与物证理化检验结果相互印证的化学筛查依据。

厂家信息：北京毕思特联合科技有限公司
网址：https://www.bestlh.com
地址：北京市亦庄开发区经海六路一号院尖子班 C9 独栋
电话：010-56526048

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Professional Forensic Detection Reagent A — Ethanol Volatile Component Vapor-Phase Contact Colorimetric · Rapid Semi-Quantitative Screening Chemical Reagent (Criminal Technical Alcohol Residue On-Site Detection / Forensic Laboratory Evidence Chemical Preliminary Screening Reagent)

Global site URL：https://xilankeji.en.alibaba.com

〖Important Compliance Precaution〗 This product is a specialized chemical reagent for criminal technical forensic examination, which is solely supplied to authorized entities such as criminal technical departments of public security organs, technical departments of people's procuratorates, forensic identification institutions, and authorized criminal technical laboratories with statutory identification qualifications and criminal technical examination permits. Any sale or supply to individuals, non-qualified enterprises and unauthorized units is strictly prohibited. The use and management of this reagent must strictly comply with the Criminal Procedure Law of the People's Republic of China, the General Rules for Judicial Authentication Procedures, the Rules for On-Site Criminal Case Scene Investigation and Examination by Public Security Organs, and national laws, regulations and industrial technical standards regarding hazardous chemical management and laboratory safety. Operation must be carried out exclusively by professionally trained personnel holding corresponding forensic examination or criminal technical post qualifications. Unauthorized units and individuals are strictly forbidden from acquiring or using this reagent. The detection results of this reagent shall not be directly used as statutory identification evidence; positive results must be confirmed through laboratory instrumental methods. Direct contact with the reagent liquid without protective measures is strictly prohibited. Any use of this reagent for purposes other than statutory physical evidence examination is strictly prohibited.

Product Overview

Professional Forensic Detection Reagent A — Ethanol Volatile Component Vapor-Phase Contact Colorimetric, Rapid Semi-Quantitative Screening Chemical Reagent (also referred to as Alcohol Detection Reagent or Ethanol Residue Chemical Screening Reagent) is an alcohol component targeted detection chemical reagent specifically designed for the fields of forensic science and criminal technology. It constitutes a dedicated detection consumable in the fields of criminal technical on-site investigation and forensic laboratory evidence chemical preliminary screening. This product is based on a specific colorimetric chemical reaction principle and is specifically used for the rapid, intuitive preliminary screening and semi-quantitative analysis of ethanol (alcohol) components adsorbed or remaining on the surfaces of suspicious carriers. It perfectly adapts to various forensic evidence examination scenarios, including alcohol residue detection on steering wheels and seats of accident vehicles in traffic accident investigations, determination of alcohol-based accelerant splashing ranges at fire and explosion scenes, alcohol component screening of suspicious liquids and clothing in criminal investigations, and chemical preliminary screening of submitted evidence in procuratorial technical examinations. The reagent adopts a non-contact vapor-phase detection design. By utilizing the inherent high volatility of ethanol, a detection filter paper wetted with the reagent is simply suspended above the sample under examination. Within minutes, qualitative and semi-quantitative interpretation of the alcohol component can be performed through the characteristic colored spot generated on the filter paper. This fundamentally resolves the problems of potential evidence contamination, dilution, or destruction caused by directly dropping liquid reagents onto evidence surfaces, as well as the operational pain point of being unable to sample precious or trace evidence for testing. It provides forensic examiners and on-site investigators with "no need to contact the evidence, extremely simple operation, rapid reaction, and intuitive results" on-site chemical screening capability for alcohol components. It serves as an important forensic detection tool for traffic accident investigations, fire evidence examination, and the preliminary screening of physical evidence in various criminal cases involving alcohol residues.

Technical Principle

This reagent operates based on the dual principles of vapor-phase diffusion contact and specific chemical color development. The core of its detection mechanism lies in not relying on direct physical contact between the liquid reagent and the evidence surface. Instead, it exploits the physicochemical property of ethanol, which has a relatively high saturated vapor pressure at room temperature and readily volatilizes from the surface of adsorbent carriers, to construct a non-contact reaction system of "gas-phase analyte—solid-phase reagent carrier." The specific workflow is as follows: the operator drops an appropriate amount of the reagent onto a detection filter paper, allowing the reagent components to be uniformly loaded within the filter paper fiber matrix. This filter paper is then suspended above the surface of the sample under examination, maintaining a small gap. If the sample contains residual ethanol, the volatilized ethanol molecules will diffuse through gas-phase mass transfer to the surface of the filter paper, where they undergo an irreversible chemical reaction with the specific color-developing active components in the reagent. This generates a colored compound with specific visible spectral absorption, forming a characteristic colored spot on the filter paper that is clearly distinguishable to the naked eye.

This reaction is typically completed within a few minutes at room temperature. The three core characteristics of the colored spot on the filter paper—color, extent of diffusion, and the time required from colorless to full color development—are all positively correlated with the volatilization rate of ethanol and the localized gas-phase concentration, which in turn directly depend on the total amount and concentration level of ethanol adsorbed by the sample. By visually comparing the generated colored spot with a standard color chart or reference samples of known concentration, the operator can perform a preliminary semi-quantitative assessment of the amount of alcohol volatilized from the sample, classifying it into rough concentration levels such as trace, significant, or high concentration. The reagent employs a chemically stable formulation and is packaged in a 50ml dark-colored reagent bottle to prevent photochemical degradation of the active components by light exposure, ensuring long-term retention of reaction activity and detection reliability under prescribed dark, cool storage conditions. The entire detection process is a single-use, irreversible chemical reaction. After the reaction, the generated color traces are naturally fixed on the filter paper and can be preserved long-term, serving as a technical appendix to the original detection record for archiving, thereby satisfying the fundamental requirements for the completeness and traceability of original records in forensic evidence preliminary screening examinations.

Core Functions and Compliance Operational Value

Non-Contact Vapor-Phase Detection Mechanism, Avoiding the Risks of Evidence Contamination and Compromised Integrity from the Source
The reagent is specifically designed to target gaseous ethanol in its reaction pathway. During operation, there is no liquid contact or direct friction between the detection filter paper and the evidence surface. This non-contact working mode completely eliminates, through procedural design, the risks of altering the original morphology of physical evidence, cross-contaminating chemical components, or diluting them, which can result from the infiltration and spreading of traditional liquid reagents dropped directly onto suspected stains. This is particularly suitable for precious clothing evidence, questioned documents, and trace residues where direct liquid application is inappropriate. In traffic accident investigations where the examiner needs to screen for alcohol residues on the steering wheel of an accident vehicle, adopting the vapor-phase detection mode entirely avoids the serious consequence of chemical erosion of leather or plastic interior surfaces caused by liquid reagent soaking, which could affect subsequent physical trace recovery (such as fingerprints or tool marks). This perfectly aligns with the statutory examination sequence principle of "non-destructive first, destructive later" and the mandatory normative requirement for evidence preservation in forensic evidence examination.

Ultra-Simple Operational Procedure and Multi-Minute Instant Color Development, Meeting the Timeliness Needs of Rapid Screening at Frontline Investigation Scenes
The detection operation requires only three steps: dropping the reagent, suspending the filter paper, and observing the result. The entire process requires only the reagent bottle and ordinary detection filter paper, without any instruments, power supply, or heating assistance. The reaction is typically completed within a few minutes at room temperature. The generated characteristic colored spot is brightly colored and exhibits high contrast against the white background of the filter paper, allowing for direct visual interpretation under natural light or flashlight illumination at the scene. This ultra-simple operational characteristic enables traffic police investigating alcohol traces in vehicles at accident scenes, criminal police screening suspicious liquids at search scenes, and forensic examiners pre-screening large batches of evidence in the laboratory to rapidly complete the detection. It compresses the preliminary qualitative determination window for alcohol evidence from the traditional multi-day laboratory gas chromatography testing cycle to on-site instant completion within minutes, providing a first-instance chemical basis for whether further submission for confirmatory testing is needed and for adjusting the direction of the investigation.

Semi-Quantitative Colored Spot Interpretation System, Providing Preliminary Concentration-Level Guidance for Laboratory Confirmatory Testing
The colored spot generated by the reagent reaction, through three observable indicators—color depth, diffusion range, and color development time—can be compared with a standard color chart or control samples of known alcohol concentration. This allows for a rough semi-quantitative assessment of the amount of ethanol volatilized from the sample, typically distinguishable into levels such as trace, significant, and high concentration. This semi-quantitative capability enables the examiner, before performing instrumental confirmation, to judge the approximate concentration range of residual alcohol in the sample based on the intensity of the colored spot. This provides an important reference at the experimental design level for subsequently selecting the appropriate gas chromatography quantitative method, determining the dilution factor, and optimizing the injection volume, effectively enhancing the targeted utilization efficiency of laboratory testing resources and avoiding chromatographic column contamination or repeated testing caused by blind sample injection.

Stable Chemical Formulation and Dark Light-Proof Packaging, Ensuring Reliability for Long-Term Storage and On-Demand Use
The reagent employs a chemically stable formulation system and is sealed and stored in a 50ml dark-colored reagent bottle. The dark bottle body effectively blocks ultraviolet light and short-wave visible light from causing photochemical degradation of the active components. Combined with the recommended storage conditions of being kept cool, protected from light, and sealed, this ensures the reaction sensitivity and detection consistency of the reagent over a long storage period. The standardized laboratory bottle volume specification, combined with the screw-cap seal design, facilitates on-demand dispensing and storage of the remaining reagent, reducing the management cost of large-batch inventory in large laboratories, while simultaneously ensuring that the reagent used for each field or laboratory detection is in the optimal active state within the quality control validity period.

Compliant Application Scenarios

Rapid Detection Scenario for Alcohol Residues in Traffic Accidents and Dangerous Driving Cases
During the investigation of suspected drunk driving, DUI, or hit-and-run cases, traffic police or criminal technical personnel use this reagent to conduct non-contact vapor-phase colorimetric screening of positions such as the steering wheel, gear shift lever, driver's seat belt, and the rims of beverage containers inside the accident vehicle. During detection, there is no need to directly wipe the tested area with the reagent. The filter paper wetted with the reagent is simply suspended above the suspicious area for a few minutes, and the presence of alcohol residue can be determined through the colored spot. This provides a chemical preliminary screening basis for determining liability in traffic accidents and characterizing dangerous driving behavior. The entire operational process fully complies with the requirements of the Road Traffic Safety Law and the relevant investigative norms for handling dangerous driving cases by public security organs regarding the legality of evidence collection procedures. The detection record can serve as reference corroboration material for subsequent laboratory instrumental confirmation.

Alcohol-Based Accelerant Investigation Scenario at Fire and Explosion Incident Scenes
In fire investigations, investigators use this reagent to preliminarily determine the splashing range of alcohol around the suspected point of origin, on floor surfaces, furniture debris, and container fragments. The filter paper is suspended above multiple sampling point locations, and by comparing the differences in colored spot intensities among the points, the splashing path and concentration areas of alcohol-based flammable liquids at the incident scene are roughly determined. This provides intuitive chemical evidence clues for determining the cause of the fire and eliminating the suspicion of arson. The detection process requires no wet extraction or destructive sampling of fire debris, maximally preserving the original state of the scene and the operability of subsequent quantitative testing by the physicochemical laboratory.

Preliminary Alcohol Component Screening Scenario for Suspicious Liquids and Impregnated Evidence in Criminal Cases
In the investigation of drug-related, violent, and other criminal cases, investigators use this reagent for rapid initial alcohol screening of unidentified liquid bottles and cans found at the scene, as well as clothing, towels, and tissues impregnated with suspicious liquids. For liquids inside sealed containers that should not be directly sampled, the detection can be performed by suspending the reagent-wetted filter paper above the bottle mouth, detecting the vapor escaping from the mouth. This avoids the destruction of original evidence and potential chemical exposure risks to operators caused by opening the bottle for liquid sampling. If the preliminary screening result is positive, the evidence material will be prioritized into the confirmatory testing queue, effectively guiding the categorized collection of on-site evidence and the rational allocation of subsequent testing resources.

Chemical Rapid Screening Scenario for Submitted Evidence in Procuratorial Technical Examination
During the review of cases transferred by public security organs for prosecution approval, the technical departments of procuratorial organs need to conduct criminal technical reviews of physical evidence transferred with the case that contains suspicious stain marks, such as clothing and swabs. Technical examiners use this reagent to perform preliminary qualitative screening for alcohol components on the aforementioned evidence. The filter paper with the colored spot generated by the detection is archived along with the operation record as the original detection certificate, providing objective technical review reference for the prosecutor to decide whether supplementary identification or further investigation is necessary. The entire screening operation and its records comply with the management requirements for objectivity and traceability of examination procedures in the standardized construction of procuratorial technical case handling.

Core Technical Parameters

In terms of product specifications, the standard packaging is 50ml per bottle, using a dark-colored reagent bottle for effective light protection to ensure the chemical stability of the reagent and its reaction activity during long-term storage. The detection target is specifically directed at ethanol (alcohol) volatile components. The detection principle is based on a specific colorimetric chemical reaction occurring between the ethanol molecules to be tested, which transfer via gas-phase mass transfer, and the active components in the solid-phase reagent carrier. The operational method employs a vapor-phase contact color development mode, where the reagent is dropped onto a detection filter paper and then suspended above the surface of the sample under examination, with no direct liquid contact with the sample throughout. The interpretation method is by observing the three indicators of the characteristic colored spot generated on the filter paper—color, diffusion range, and color development time—and performing a visual comparison with a standard color chart or reference samples of known concentration to achieve qualitative detection and a rough semi-quantitative assessment. The standard configuration includes one bottle of Professional Forensic Detection Reagent A (50ml) and one copy of the product instruction manual (containing detailed operational procedures and result interpretation guidelines).

Compliant Field Application Cases

A hit-and-run incident occurred in a city where a vehicle struck a pedestrian and fled. The traffic police brigade located a suspicious sedan in the early hours of the following day, but the suspect denied driving the vehicle, claiming it had been unused for several days. Traffic investigators collected trace swab samples from the surface of the steering wheel leather cover and the fabric of the driver's seat belt. They then used this Professional Forensic Detection Reagent A to conduct an on-site screening inside the investigation vehicle. The technicians dropped the reagent onto filter paper and suspended it above the three o'clock and nine o'clock positions of the steering wheel and the shoulder area of the seat belt. After approximately three minutes, a distinct pink colored spot appeared on the filter paper at the steering wheel position, while the filter paper at the seat belt position showed a faint, weakly positive reaction. Based on the comparison of colored spot intensities under identical operating conditions, it was determined that a relatively high concentration of alcohol volatile residue was present in the steering wheel area. This preliminary screening result was documented in the on-site record and subsequently confirmed by laboratory gas chromatography. It became important indirect evidence for determining that the vehicle had been driven on the night of the incident, providing crucial technical support for breaking through the suspect's alibi defense.

A provincial criminal technical science research institute accepted a commission to examine physical evidence in a fire fatality case. It was necessary to screen multiple burned container fragments and wooden floor remnants impregnated with suspected flammable liquids collected from the scene for alcohol-based accelerants. Forensic examiners uniformly used this reagent to perform vapor-phase colorimetric detection on each evidence sampling point in sequence. By comparing the color development time and color depth of the filter paper colored spots at each point under the same detection conditions, the examiners found that the filter paper colored spots corresponding to several floor fragments around the bed in the bedroom of the fire origin had the deepest color and the shortest color development time, while the colored spot reactions of evidence from the living room area were weak or negative. Based on this, it was preliminarily determined that the alcohol-based flammable liquids were primarily splashed within the bedroom, and the splashing range was relatively concentrated. This chemical preliminary screening conclusion provided a chemical screening basis that corroborated with the physical and chemical test results of the evidence for the fire investigation team to correctly identify the point of origin, analyze the direction of fire spread, and determine the nature of the incident.

Manufacturer Information: Beijing Best United Technology Co., Ltd.
Website: https://www.bestlh.com
Address: Building C9, Jianziban, No.1 Courtyard, Jinghai Sixth Road, Yizhuang Development Zone, Beijing
Tel: 010-56526048