QB/T 4975-2016Safety technical specifications for using flammable refrigerants in household and similar room air conditioner industry (English PDF)

0.25 mg/kg, the quantification limit is 0.83 mg/kg; the detection limit of ion

chromatography-inductively coupled plasma mass spectrometry is 0.010 mg/kg, the

quantification limit is 0.033 mg/kg.

3.1 Principle

After the sample is extracted by the alkaline leaching solution, the hexavalent

chromium in the leaching solution reacted with diphenylcarbazide in an acidic solution,

to form a purple-red complex, which was determined by spectrophotometry, at a

wavelength of 540 nm.

3.2 Reagents

Unless otherwise specified, the reagents are of analytical grade. The water is the first

grade water, which is specified in GB/T 6682.

3.3 Instruments

3.4 Analytical procedures

3.5 Result calculation

Calculate the hexavalent chromium, X, in the specimen, according to formula (1).

3.6 Recovery and precision

When the standard addition concentration is in the range of 0.5 mg/L ~ 10.0 mg/L, the

recoveries are in the range of 88.4% ~ 102.9%, the precisions are in the range of 1.9%

~ 7.1%.

3.7 Tolerance

The absolute difference, between the results of two independent determinations, which

are obtained under repeatability conditions, shall not exceed 10% of the arithmetic

mean.

4.1 Principle

After the samples are extracted with alkaline leaching solution, the leaching solution is

determined by ion chromatography-inductively coupled plasma mass spectrometry,

AND quantified by external standard method.

4.2 Reagents

Unless otherwise specified, the reagents are of analytical grade. The water is the first

grade water, which is specified in GB/T 6682.

4.3 Instruments and equipment

4.3.1 Ion chromatography-inductively coupled plasma mass spectrometer.

4.3.2 Ultrasonic generator. Constant temperature (60 ± 1) °C.

4.3.3 Analytical balance. Sensitivity 0.0001 g.

4.3.4 Graduated centrifuge tube (polyethylene or polypropylene). Specification 50 mL.

4.4 Analytical procedures

4.4.1 Pre-treatment of sample

Accurately weigh (0.5 g ~ 2 g, accurate to 0.0001 g) of the sample, into a 50 mL

graduated centrifuge tube. Add 20.0 mL of extract (4.2.8) and 0.5 mL of buffer (4.2.9).

Completely submerge the sample in the extract. Shake well. Carry out ultrasonic

extraction, at 60 °C for 20 min. Take it out. After cooling to room temperature, use

water to make the volume to 25.0 mL. Add 2.0 g of activated carbon powder. Shake

well. Use filter paper to filter it. Discard the first 1 mL of filtrate. Collect the filtrate.

Use microporous filter membrane (4.2.13) to filter the collected filtrate. Prepare for

determination. Meanwhile do a reagent blank test.

4.4.3 Determination

The instrument is tuned and set, to measure the standard curve solution, reagent blank

solution, sample solution in sequence. See Appendix A, for instrument reference

conditions.

4.6 Recovery and precision

When the standard concentration is in the range of 0.10 mg/kg ~ 10 mg/kg, the recovery

rate is 86.0% ~ 103.7% AND the precision is in the range of 1.1% ~ 8.1%.

4.7 Tolerance

The absolute difference, between the results of two independent determinations, which

are obtained under repeatability conditions, is not more than 10 % of the arithmetic

mean.

Appendix A

(Informative)

Reference conditions of instrument

A.1 Ion chromatography conditions

The ion chromatography conditions are as follows.

A.2 Inductively coupled plasma mass spectrometry conditions

Inductively coupled plasma mass spectrometry conditions are as follows.

Appendix B

(Informative)

Ion chromatography-mass spectrograms of standard solutions and samples

See Figure B.1 and Figure B.2, for the ion chromatogram-mass spectrum of the standard

solution and sample.

QB/T 5291-2018

LIGHT INDUSTRY STANDARD OF

THE PEOPLE'S REPUBLIC OF CHINA

ICS 71.100.70

Classification No.. Y42

Filing No.. 65903-2018

Determination of hexavalent chromium in cosmetics

Issued on. OCTOBER 22, 2018

Implemented on. APRIL 01, 2019

Issued by. Ministry of Industry and Information Technology of PRC

Table of Contents

Foreword... 3

Introduction... 4

0.25 mg/kg, the quantification limit is 0.83 mg/kg; the detection limit of ion

chromatography-inductively coupled plasma mass spectrometry is 0.010 mg/kg, the

quantification limit is 0.033 mg/kg.

3.1 Principle

After the sample is extracted by the alkaline leaching solution, the hexavalent

chromium in the leaching solution reacted with diphenylcarbazide in an acidic solution,

to form a purple-red complex, which was determined by spectrophotometry, at a

wavelength of 540 nm.

3.2 Reagents

Unless otherwise specified, the reagents are of analytical grade. The water is the first

grade water, which is specified in GB/T 6682.

3.3 Instruments

3.4 Analytical procedures

3.5 Result calculation

Calculate the hexavalent chromium, X, in the specimen, according to formula (1).

3.6 Recovery and precision

When the standard addition concentration is in the range of 0.5 mg/L ~ 10.0 mg/L, the

recoveries are in the range of 88.4% ~ 102.9%, the precisions are in the range of 1.9%

~ 7.1%.

3.7 Tolerance

The absolute difference, between the results of two independent determinations, which

are obtained under repeatability conditions, shall not exceed 10% of the arithmetic

mean.

4.1 Principle

After the samples are extracted with alkaline leaching solution, the leaching solution is

determined by ion chromatography-inductively coupled plasma mass spectrometry,

AND quantified by external standard method.

4.2 Reagents

Unless otherwise specified, the reagents are of analytical grade. The water is the first

grade water, which is specified in GB/T 6682.

4.3 Instruments and equipment

4.3.1 Ion chromatography-inductively coupled plasma mass spectrometer.

4.3.2 Ultrasonic generator. Constant temperature (60 ± 1) °C.

4.3.3 Analytical balance. Sensitivity 0.0001 g.

4.3.4 Graduated centrifuge tube (polyethylene or polypropylene). Specification 50 mL.

4.4 Analytical procedures

4.4.1 Pre-treatment of sample

Accurately weigh (0.5 g ~ 2 g, accurate to 0.0001 g) of the sample, into a 50 mL

graduated centrifuge tube. Add 20.0 mL of extract (4.2.8) and 0.5 mL of buffer (4.2.9).

Completely submerge the sample in the extract. Shake well. Carry out ultrasonic

extraction, at 60 °C for 20 min. Take it out. After cooling to room temperature, use

water to make the volume to 25.0 mL. Add 2.0 g of activated carbon powder. Shake

well. Use filter paper to filter it. Discard the first 1 mL of filtrate. Collect the filtrate.

Use microporous filter membrane (4.2.13) to filter the collected filtrate. Prepare for

determination. Meanwhile do a reagent blank test.

4.4.3 Determination

The instrument is tuned and set, to measure the standard curve solution, reagent blank

solution, sample solution in sequence. See Appendix A, for instrument reference

conditions.

4.6 Recovery and precision

When the standard concentration is in the range of 0.10 mg/kg ~ 10 mg/kg, the recovery

rate is 86.0% ~ 103.7% AND the precision is in the range of 1.1% ~ 8.1%.

4.7 Tolerance

The absolute difference, between the results of two independent determinations, which

are obtained under repeatability conditions, is not more than 10 % of the arithmetic

mean.

Appendix A

(Informative)

Reference conditions of instrument

A.1 Ion chromatography conditions

The ion chromatography conditions are as follows.

A.2 Inductively coupled plasma mass spectrometry conditions

Inductively coupled plasma mass spectrometry conditions are as follows.

Appendix B

(Informative)

Ion chromatography-mass spectrograms of standard solutions and samples

See Figure B.1 and Figure B.2, for the ion chromatogram-mass spectrum of the standard

solution and sample.

......