Procedure— [Note—It is recommended to increase the temperature of the transfer line between runs to eliminate any potential condensation of solvents. ] Separately inject (following one of the headspace operating parameter sets described in Table 5) equal volumes of headspace (about 1.0 mL) of the Class 1 Standard Solution, Class 2 Mixture A Standard Solution, Class 2 Mixture B Standard Solution, and Test Solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. If a peak response of any peak, other than a peak for 1,1,1-trichloroethane, in the Test Solution is greater than or equal to a corresponding peak in either the Class 1 Standard Solution or either of the two Class 2 Mixture Standard Solutions, or a peak response of 1,1,1-trichloroethane is greater than or equal to 150 times the peak response corresponding to 1,1,1-trichloroethane in the Class 1 Standard Solution, proceed to Procedure B to verify the identity of the peak; otherwise the article meets the requirements of this test.
操作过程 【注-建议增加传输线路间的温度，以消除任何潜在冷凝溶剂】根据下表5的一项设定顶空操作参数，将相同体积的（约1.0mL）一级标准溶液，二级混匀液A标准溶液，二级混匀液B标准溶液和待测液分别顶空进样，记录色谱并测量主峰的响应值。若待测液任何一个峰的响应值大于或等于一级标准溶液或者两个二级混匀液（A和B）标准溶液相对应的峰响应值，或1,1,1-三氯乙烷峰响应值大于一级标准溶液中1,1,1-三氯乙烷峰响应的150倍，根据操作B继续操作以鉴别峰；否则待测物符合检测标准。
表5. 顶空操作参数Table 5. Headspace Operating Parameters 顶空操作参数设臵 1 2 3 平衡温度（℃） 80 105 80 平衡时间（分钟） 60 45 45 传输管温度（℃）（如果合适）85 110 105 注射温度（℃）（如果合适） 80-90 105-115 80-90 载气：适当压力的氮气或者氦气 加压时间 （秒）（如果合适）≥60 ≥60 ≥60 进样量（mL） 1 1 1 *或参照生产厂家建议，尽可能满足方法要求，在达到灵敏度要求前提下进进样量尽可能少。 Procedure B—
Class 1 Standard Stock Solution, Class 1 Standard Solution, Class 2 Standard Stock Solutions, Class 2 Mixture A Standard Solution, Class 2 Mixture B Standard Solution, Test Stock Solution, Test Solution, and Class 1 System Suitability Solution— Prepare as directed for Procedure A. 操作B
一级标准储备液，一级标准溶液，二级标准储备液，二级混匀液A标准溶液，二级混匀液B标准溶液，待测储备液，待测液和一级系统适应性溶液――配制方法如操作A。
Chromatographic System (see Chromatography 621)— The gas chromatograph is equipped with a flame-ionization detector and a 0.32-mm × 30-m fused-silica column coated with a 0.25-μm layer of phase G16 or a 0.53-mm × 30-m wide-bore column coated with a 0.25-μm layer of phase G16. The carrier gas is nitrogen or helium with a linear velocity of about 35 cm per second and a split ratio of 1:5. [Note—The split ratio can be modified in order to optimize sensitivity. ] The column temperature is maintained at 50 for 20 minutes, then raised at a rate of 6 per minute to 165, and maintained at 165 for 20 minutes. The injection port and detector temperatures are maintained at 140 and 250, respectively. Chromatograph the Class 1 Standard Solution and the Class 1 System Suitability Solution, and record the peak responses as directed for Procedure: the signal-to-noise ratio of benzene in the Class 1 Standard Solution is not less than 5; the signal-to-noise ratio of each peak in the Class 1 System Suitability Solution is not less than 3; and the resolution,
R, between acetonitrile and cis-dichloroethene in the Class 2 Mixture A Standard Solution is not less than 1.0.
色谱系统（参见色谱法<621>）――气相色谱由氢火焰离子检测器，0.32mm×30m，装填有厚度为0.25μm厚的G16固定相的熔融石英柱组成。石英柱也可由装填有0.25μm厚的G16固定相，0.53mm×30m大内径开管柱。载气为线速35cm/秒，分流比为1：5的氮气或者氦气。【注：为了优化灵敏度可对分流比进行调整】柱温在50℃维持20分钟，然后以6℃/分钟的速率升至165℃，然后在165℃维持20分钟。进样口和检测器温度分别维持在140℃和250℃。记录一级标准溶液，一级系统适应性溶液和二级系统适应性溶液 的色谱，按下列操作记录峰响应值：一级标准溶液中苯的信噪比不得小于5；一级系统适应性溶液中的每个峰的信噪比不得小于3；在二级系统适应性溶液中，乙腈和三氯乙烯的分离度R不得小于1.0。
Procedure— [Note—It is recommended to increase the temperature of the transfer line between runs to eliminate any potential condensation of solvents. ] Separately inject (following one of the headspace operating parameter sets described in Table 5) equal volumes of headspace (about 1.0 mL) of the Class 1 Standard Solution, the Class 2 Mixture A Standard Solution, the Class 2 Mixture B Standard Solution, and the Test Solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. If the peak response(s) in the Test Solution of the peak(s) identified in Procedure A is/are greater than or equal to a corresponding peak(s) in either the Class 1 Standard Solution or either of the two Class 2 Mixture Standard Solutions, proceed to Procedure C to quantify the peak(s); otherwise the article meets the requirements of this test.
操作过程―【注-建议增加传输线路间的温度，以消除任何潜在冷凝溶剂】根据表5的一项设定顶空操作参数，将相同体积的（约1.0mL）一级标准溶液，二级混匀液A标准溶液，二级混匀液B标准溶液和待测液分别顶空进样，记录色谱并测量主峰的响应值。若待测
液中任何一个峰（在操作A中区别出）的响应值大于或等于一级标准溶液 或者两个二级标准液（A和B）标准溶液 相对应的峰响应值，根据操作C继续操作以定量峰值；否则待测物符合检测标准。
Procedure C—
Class 1 Standard Stock Solution, Class 1 Standard Solution, Class 2 Standard Stock Solution A, Class 2 Mixture A Standard Solution, Test Stock Solution, Test Solution, and Class 1 System Suitability Solution— Prepare as directed for Procedure A. 操作C
一级标准储备液，一级标准溶液，二级标准储备A，二级混匀液A标准溶液，待测储备液，待测液 和一级系统适应性溶液――配制方法如操作A。
Standard Stock Solution— [note—Prepare a separate Standard Stock Solution for each peak identified and verified by Procedures A and B. For the Class 1 solvents other than 1,1,1-trichloroethane, prepare the first dilution as directed for the first dilution under Class 1 Standard Stock Solution in Procedure A. ] Transfer an accurately measured volume of each individual USP Reference Standard corresponding to each residual solvent peak identified and verified by Procedures A and B to a suitable container, and dilute quantitatively, and stepwise if necessary, with water to obtain a solution having a final concentration of 1/20 of the value stated in Table 1 or 2 (under Concentration Limit).
标准储备液――【注意－根据操作A和操作B区别和确认的峰，
配制每一个峰相对应溶剂的标准溶液】根据操作A和操作B 测定的结果精确量取一定量的USP标准品，移至适当的容器，加水稀释至定量，如有必要可逐步稀释，最终得到浓度为表1或者表2值（在浓度限下）1/20的溶液。
Standard Solution— Transfer 1.0 mL of this solution to an appropriate headspace vial, add 5.0 mL of water, apply the stopper, cap, and mix.
标准溶液--取1.0mL此溶液至顶空瓶中，加入5.0mL水，加塞、轧盖、混匀。
Spiked Test Solution— [Note—Prepare a separate Spiked Test Solution for each peak identified and verified by Procedures A and B. ] Transfer 5.0 mL of Test Stock Solution to an appropriate headspace vial, add 1.0 mL of the Standard Stock Solution, apply the stopper, cap, and mix.
示踪溶液（掺料溶液）――【注意－根据操作A和操作B区别和确认的峰，配制每一个峰相对应溶剂的示踪溶液】取5.0mL待测储备液至顶空瓶中，加入1.0mL标准溶液 ，加塞、轧盖、混匀。
Chromatographic System (see Chromatography 621)— [Note—If the results of the chromatography from Procedure A are found to be inferior to those found with Procedure B, the Chromatographic System from Procedure B may be substituted. ] The gas chromatograph is equipped with a flame-ionization detector and a 0.32-mm × 30-m fused-silica column coated with a 1.8-μm layer of phase G43 or a 0.53-mm × 30-m wide-bore column coated with a 3.0-μm layer of phase G43. The carrier