ASTM-D3524:14(R2020) pdf free download – Standard Test Method for Diesel Fuel Diluent in Used Diesel Engine Oils by Gas Chromatography.
6.2 Data Acquisition System:
6.2. 1 Integrator—Means must be provided for determining the accumulated area under the chromatogram. This can be done by means of an electronic integrator or computer based chromatography data system. The integrator/computer system must have chromatographic software for measuring the retention times and areas of eluting peaks (peak detection mode). The electronic range of the integrator/computer (for example, I V. 10 V) must be within the linear range of the detector/ electrometer system used. It is desirable that the system be capable of subtracting each area slice of a blank run from the corresponding area slice of a sample run.
NOTh 4—Best precision and automatic operation can be achieved with an electronic integration system using a computer (or data acquisition and control of the gas chromatograph.
NOTF. 5—Some gas chromatographs have an algorithm built into their operating software that allows a mathematical model of the baseline prohie to he stored in memory. This prohie is automatically subtracted from the detector signal on subsequent sample analyses to compensate for any baseline offset. Some integration systems also store and automatically subtract a blank analysis from subsequent analytical determinations.
6.3 Column—Any column and conditions may be used, provided that under the conditions of the test, the separations occur in order of increasing boiling points. Moreover, the column must meet the performance requirements described in 8.2.1. The column resolution, R, shall be at least 3 and not more than 8. Since a stable baseline is an essential requirement of this method, compensation is required for column bleed, septum bleed, detector temperature control, constancy of carrier gas flow and instrument drift.
6.4 Flow ‘ontrollers—The gas chromatograph must be equipped with mass flow controllers capable of maintaining carrier gas flow constant to ± I % over the full operating temperature range of the column. The inlet pressure of the carrier gas supplied to the gas chromatograph must be sufliciently high to compensate for the increase in column hack- pressure as the column temperature is raised. An inlet pressure of 550 kPa (8() psig) has been found to be satisfactory with the columns described in Table 1.
6.5 Sample Introduction Devices:
6.5.1 Micro Syringe—A micro syringe, usually 10 jiL. is used for sample introduction.
6.5.2 Automatic sampling devices that reproducibly inject the same volume are highly recommended. The sample introduction devices should operate in a synchronous manner with the gas chromatograph.
6.6 Vial, 15 niL, screw cap.
7. Reagents and Materials
7.1 Purity of Reagents—Reagent grade chemicals shall he used in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available.’ Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.