HJ 1073-2019Water quality--Determination of naphthol--High performance liquid chromatography (English PDF)

7.1 Collection and storage of samples

The layout of sampling points and the collection of samples are performed in accordance with HJ/T 91, HJ 91.1 or HJ/T 164, GB 17378.3 Regulations. Collect the sample into the sampling bottle (6.3), add 0.5 g of ascorbic acid (5.4) to each liter of sample, and wait for it to completely dissolve.

After the solution, adjust the pH of the sample to 1-2 with hydrochloric acid solution (5.8) or sodium hydroxide solution (5.10) and seal. At 4 °C Store and refrigerate under dark, refrigerated, and complete analysis within 14 days.

7.2 Preparation of test specimens

C18 solid phase extraction column (5.15) was fixed on the solid phase extraction device (6.5), and 9 ml of methanol (5.2) and 9 ml were used in this order.

The hydrochloric acid solution (5.9) was activated and the column head was kept wet at all times. The sample (7.1) was equilibrated to room temperature and shaken. According to the sample Content of target compound, measure 10.0 ml ~ 50.0 ml of the sample in the sample bottle (6.4), and then make the sample at 3 ~ 4 ml/min the flow rate passed through the extraction column. Rinse the vial twice with 5 ml of water just before the column packing is exposed to air. detergent Transfer to the column and discard the flow-through. After extruding or draining water from the extraction column under pressure, wash with 10.0 ml of methanol (5.2) Take off, receive the eluate in a 10 ml sample bottle (6.4), after the initial eluate flows out, close the piston and soak the solid phase extraction Column for at least 5 min. Open the plunger, collect all the eluent, make up to 10.0 ml with methanol (5.2), mix well and use a microwell Filter membrane (5.16) is filtered, to be tested.

Note 1. For samples with complex matrix and unknown organic content, in order to avoid penetration, two solid phase extraction columns can be used to extract different bodies.

Volume of the same sample. For example, extract 10.0 ml and 20.0 ml samples, respectively.

When the former is 20% lower, it means that the adsorption capacity of the latter has reached saturation. It is necessary to appropriately reduce the sample volume or dilute the sample before solid phase extraction.

Note 2. For clean samples (excluding high salt water and sea water), the sample (7.1) can also be filtered through a microporous membrane (5.16) and directly Inject. The detection limit of the method can refer to the relevant data of both the sampling volume and the eluent volume being 10.0 ml.

7.3 Preparation of blank samples

Use experimental water to replace the sample, and follow the same steps as in sample preparation (7.2) to prepare a blank sample.

8.1 Instrument Reference Conditions

Mobile phase A. acetonitrile (5.1), mobile phase B. methanol solution (5.11). Elution procedure. mobile phase A/mobile phase B = 47/53 (V/V); flow rate. 1.2 ml/min; injection volume. 10.0 µl; column temperature. 35 ° C;

Detector. fluorescence detector; excitation wavelength. 228 nm;

Emission wavelength. When measuring 1-naphthol and 2-naphthol at the same time, select 425 nm as the quantitative detection wavelength and 435 nm as the quantitative detection wavelength.

Auxiliary qualitative wavelength; when only 2-naphthol is measured or when 2-naphthol is interfered at 425 nm, 360 nm is selected for quantification Detection wavelength, 350 nm as auxiliary qualitative wavelength.

For samples with complex matrices, gradient elution should be used. See Table 1 for the gradient elution reference procedure.

Table 1 Reference procedure for gradient elution

Time/min Mobile phase A /% Mobile phase B /%

8.2 Calibration

8.2.1 Preparation of standard series

Take an appropriate amount of Naphthol Mixed Standard Solution II (5.14) or Naphthol Mixed Standard Solution I (5.13) in 10 ml.

In a brown volumetric flask, make up to volume with methanol (5.2) and prepare a standard series containing at least 5 concentration points. Standard series solution the preparation and its reference concentration are shown in Table 2.

Table 2 Standard series solution preparation and its reference concentration

8.2.2 Establishment of the standard curve According to the instrument reference conditions (8.1), the standard series solution (8.2.1) is sequentially injected from low concentration to high concentration, and Detect the target compound and record the retention time and peak height or area. Based on the mass of the target compound in each standard series solution Degree (µg/L) is the abscissa, and its corresponding peak height or area is used as the ordinate to establish a standard curve.

8.2.3 Chromatogram of standard sample

Figure 1 shows the chromatogram of gradient elution of 1-naphthol and 2-naphthol standard samples (500 µg/L) under the reference conditions of the instrument (8.1).

Figure (emission wavelength of 425 nm). Figure 2 shows the gradient of 2-naphthol standard sample (1.00 mg/L) under the reference condition of the instrument (8.1).

Eluted chromatogram (360 nm emission).

1-2-naphthol; 2--1-naphthol.

Figure 1 Gradient elution chromatogram of naphthol standard sample (emission wavelength of 425 nm)

1-2-naphthol; 2--1-naphthol.

Figure 2 Gradient elution chromatogram of naphthol standard sample (emission wavelength 360 nm)

8.3 Determination of sample

Test the sample (7.2) according to the same instrument conditions as the standard curve establishment (8.2.2).

8.4 Blank test

The blank sample (7.3) was measured under the same instrument conditions as the sample measurement (8.3).

9.1 Qualitative analysis

Qualitatively based on retention time, or the peak height ratio of the target compound at different emission wavelengths in the sample and the standard sample Comparison (its relative deviation should be <=5%) assists qualitative analysis.

9.2 Result calculation

The mass concentration (µg/L) of the target compound in the sample is calculated according to formula (1).

Note 1. When the response of the target compound in the sample exceeds the upper limit of the standard curve (10 mg/L), the sample should be appropriately diluted or reduced After the sample volume, prepare the sample (7.2).

Note 2. When the total amount of 1-naphthol and 2-naphthol in the sample needs to be calculated, the target compounds not detected are not involved in the calculation. If two targets None of the compounds were detected and their respective detection limits were reported.

9.3 Representation of results

The number of digits after the decimal point in the measurement result is the same as the detection limit of the method. A maximum of three significant digits are retained.

10.1 Precision

Uniform blanks at six laboratories for 1-naphthol and 2-naphthol spiked at 2.00 µg/L, 100 µg/L, and 1.00 mg/L the spiked samples were subjected to 6 repeated determinations. the relative standard deviations in the laboratory for the determination of 1-naphthol were 1.6% ~ 5.9%, 0.7% to 7.0%, and 0.7% to 6.2%; the relative standard deviations between laboratories were 9.2%, 9.2%, and 3.2%, respectively;

Refolding limits are 0.2 µg/L, 8.9 µg/L, and 0.089 mg/L; reproducibility limits are 0.6 µg/L, 28 µg/L, and 0.13 mg/L. The relative standard deviations in the laboratory for the determination of 2-naphthol were 1.9% to 4.1%, 0.7% to 8.5%, and 0.8% to 6.1%; the relative standard deviations between laboratories are 5.1%, 7.6%, and 5.5%; the repeatability limits are 0.18 µg/L, 10 µg/L and 0.088 mg/L; reproducibility limits are 0.33 µg/L, 23 µg/L, and 0.18 mg/L, respectively.

Uniform blanks at six laboratories for 1-naphthol and 2-naphthol spiked at 10.0 µg/L, 500 µg/L, and 9.00 mg/L the spiked samples were measured 6 times repeatedly. The relative standard deviations in the laboratory for the determination of 1-naphthol were 0.7% ~ 9.4%, 0.5% to 8.9%, and 0.6% to 3.4%; the relative standard deviations between laboratories were 10%, 5.3%, and 6.9%, respectively;

Refolding limits were 2 µg/L, 54 µg/L, and 0.41 mg/L, respectively; reproducibility limits were 3 µg/L, 89 µg/L, and 1.7 mg/L, respectively.

The relative standard deviations in the laboratory for the determination of 2-naphthol were 1.4% to 15%, 0.4% to 7.1%, and 0.5% to 5.1%;

Interlaboratory relative standard deviations were 8.5%, 3.1%, and 7.4%, respectively; repeatability limits were 2 µg/L, 43 µg/L, and 0.52 mg/L; reproducibility limits are 3 µg/L, 60 µg/L, and 1.8 mg/L, respectively.

Six laboratories spiked 1-naphthol at 2.00 µg/L, 10.0 µg/L, 100 µg/L, and 500 µg/L surface water samples the product has been tested 6 times. the relative standard deviations in the laboratory are 2.5% ~ 11%, 1.1% ~ 11%, 0.96% ~ 2.2% and 0.94% ~ 9.3%; the relative standard deviations among laboratories are 8.8%, 5.9%, 8.6% and 4.9%;

Repeatability limits are 0.38 µg/L, 1.5 µg/L, 4.5 µg/L, and 50 µg/L; reproducibility limits are 0.61 µg/L, 2.1 µg/L, 24 µg/L, and 81 µg/L.

Six laboratories have spiked 2-naphthol at concentrations of 0.10 µg/L, 0.40 µg/L, 2.00 µg/L, 10.0 µg/L, 100 µg/L and 500 µg/L surface water samples were measured 6 times. the relative standard deviations in the laboratory were 2.1% ~ 14%, 1.7% to 10%, 1.1% to 5.0%, 0.82% to 8.3%, 0.72% to 2.6%, and 0.64% to 2.7%; between laboratories the relative standard deviations were 12%, 4.0%, 11%, 6.4%, 8.9%, and 2.5%, respectively; the repeatability limits were 0.021 µg/L, 0.069 µg/L, 0.20 µg/L, 1.3 µg/L, 5.3 µg/L, and 24 µg/L; the reproducibility limits are 0.037 µg/L, 0.076 µg/L, 0.66 µg/L, 2.1 µg/L, 26 µg/L, and 42 µg/L.

Six laboratories tested three types of laboratories containing 1-naphthol at average concentrations of 48.4 µg/L, 45.7 µg/L, and 0.541 mg/L.

Industry waste water samples were measured 6 times. the relative standard deviations in the laboratory were 1.8% ~ 11% and 1.5% ~ 5.5% and 1.2% -4.3%; the relative standard deviations between laboratories were 22%, 19%, and 11%, respectively.

Six laboratories tested three types of laboratories containing 2-naphthol at average concentrations of 0.950 mg/L, 2.62 mg/L, and 153 µg/L.

Industry wastewater samples were repeated 6 times. the relative standard deviations in the laboratory ranged from 0.6% to 2.4% and 0.9% to 5.6% and 0.7% to 8.1%; the relative standard deviations between laboratories were 8.0%, 10%, and 15%.

One laboratory spiked 1-naphthol at 10.0 µg/L, 400 µg/L, and 1000 µg/L municipal wastewater samples Six replicates were performed. the relative standard deviations were 2.6%, 1.6%, and 0.3%, respectively.

One laboratory spiked 2-naphthol at concentrations of 0.50 µg/L, 10.0 µg/L, 400 µg/L, and 1000 µg/L Water samples were tested in 6 replicates. the relative standard deviations were 4.0%, 2.9%, 1.6%, and 0.3%, respectively.

One laboratory performed seawater samples spiked with 1-naphthol at 10.0 µg/L, 400 µg/L, and 1000 µg/L Six repeated determinations. the relative standard deviations were 3.0%, 2.9%, and 6.7%, respectively.

One laboratory spiked 2-naphthol at concentrations of 0.50 µg/L, 10.0 µg/L, 400 µg/L, and 1000 µg/L.

Water samples were tested in 6 replicates. the relative standard deviations were 7.0%, 3.5%, 1.9%, and 6.7%, respectively.

For a summary of method precision data, see Appendix A.

10.2 Accuracy

Uniform blanks at six laboratories for 1-naphthol and 2-naphthol spiked at 10.0 µg/L, 500 µg/L, and 9.00 mg/L the spiked samples were tested 6 times repeatedly. the relative error ranges in the laboratory for the determination of 1-naphthol were -14% to 11%,-12% to 2.0% and -17% to 0.1%; the final relative errors are -5.5% ± 19%, -4.9% ± 10%, and-6.5% ± 13%. The relative laboratory error ranges for the determination of 2-naphthol are -12% to 6.0%, -8.6% to -1.0%,-18% ~ 2.0%; the final relative errors are -4.3% ± 16%, -4.1% ± 6.0%, and -5.3% ± 14%.

Uniform blanks at six laboratories for 1-naphthol and 2-naphthol spiked at 2.00 µg/L, 100 µg/L, and 1.00 mg/L the spiked samples were tested 6 times repeatedly. the relative error ranges in the laboratory for the determination of 1-naphthol were -13% to 11%,-3.0% to 21% and -2.9% to 4.0%; the final relative errors are -3.4% ± 18%, 2.0% ± 19%, and 1.6% ± 6.6%. The relative indoor error ranges for the determination of 2-naphthol are -7.0% to 7.0%, -20% to 0.8%, and -7.5% to 8.0%; the final relative errors were -2.2% ± 10%, -5.8% ± 15%, and 1.9% ± 11%.

Six laboratories performed six repeated measurements of 1-naphthol spiked surface water samples at 10.0 µg/L and 500 µg/L Determination. The recovery ranges of standard addition in the laboratory are 88% to 99% and 89% to 103%, respectively; the final recovery values of standard addition are 94% ± 11% and 97% ± 9%.

Six laboratories conducted surface water samples spiked with 2-naphthol at concentrations of 0.40 µg/L, 10.0 µg/L, and 500 µg/L. 6 Repeated determinations. The recoveries in the laboratory range from 91% to 100%, 85% to 101% and 96% to 103% the final recoveries were 95% ± 7%, 94% ± 12% and 100% ± 5%.

Six laboratories performed 6 replicate determinations of 1-naphthol spiked surface water samples at 2.00 µg/L and 100 µg/L.

The recoveries in the laboratory range from 91% to 116% and 92% to 117% respectively; the final recoveries are 101% ± 17% and 100% ± 17%.

Six laboratories performed surface water samples spiked with 2-naphthol at 0.10 µg/L, 2.00 µg/L, and 100 µg/L 6 repeated determinations. The recovery ranges of standard addition in the laboratory are 84% ~ 114%, 86% ~ 121% and 95% ~ 119% respectively;

The final spiked recoveries were 96% ± 22%, 100% ± 23%, and 101% ± 18%.

The average concentrations of 1-naphthol in the six laboratories were 48.4 µg/L, 45.7 µg/L and 540 µg/L. The spiked concentrations were Three types of industrial wastewater samples of 50.0 µg/L, 50.0 µg/L, and 400 µg/L were tested in 6 replicates. spiked back Yields range from 80% to 101%, 82% to 116%, and 90% to 109%; the final recovery rates are 91% ± 18%, 99% ± 23%, and 99% ± 14%.

Six laboratories have average concentrations of 2-naphthol at 0.950 mg/L, 2.62 mg/L, and 153 µg/L.

Six repeated determinations of three types of industrial wastewater samples of 1.00 mg/L, 5.00 mg/L, and.200 µg/L. spiked the recoveries range from 76% to 102%, 82% to 109%, and 94% to 122%, respectively; the final recoveries are 93%.

± 18%, 103% ± 29%, and 105% ± 20%.

A laboratory performed 1-naphthol spiked municipal wastewater samples at 10.0 µg/L, 400 µg/L, and 1000 µg/L Six repeated determinations. the spiked recoveries were 87%, 91%, and 84%, respectively.

One laboratory spiked 2-naphthol at concentrations of 0.50 µg/L, 10.0 µg/L, 400 µg/L, and 1000 µg/L Water samples were tested in 6 replicates. spiked recoveries were 91%, 89%, 93%, and 87%, respectively.

One laboratory performed six seawater samples spiked with 1-naphthol at 10.0 µg/L, 400 µg/L, and 1000 µg/L Repeated determination. The spiked recoveries were 82%, 92%, and 84%, respectively.

Seawater samples spiked with 2-naphthol at 0.50 µg/L, 10.0 µg/L, 400 µg/L, and 1000 µg/L by a laboratory 6 repeated determinations of the product. the spiked recoveries were 80%, 94%, 93% and 87%, respectively;

For a summary of method accuracy data, see Appendix B.