LISUN EDX-4 ROHS 2.0 Test Equipment: A Rapid Screening Solution for Phthalates via Pyrolysis Desorption

Abstract
With the mandatory implementation of the RoHS 2.0 revised directive (EU) 2015/863 since July 22, 2019, four phthalates have been added to the list of restricted substances, supplementing the original six restricted substances (lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls, polybrominated diphenyl ethers). To meet the urgent need for rapid and accurate screening of these phthalates in electrical and electronic equipment, LISUN Group has developed the EDX-4 ROHS 2.0 Test Equipment, a dedicated system based on pyrolysis desorption technology. This study systematically introduces the composition, technical parameters, experimental methods, performance verification, and typical application cases of the EDX-4 system. Results show that the equipment achieves a minimum detection limit of 25 ppm (3× signal-to-noise ratio), a linear correlation coefficient (R²) > 0.998, and a relative standard deviation (RSD) of 5.24%, outperforming traditional methods such as PY+GC-MS (detection limit 50 ppm). It requires no chemical pretreatment, supports direct solid/liquid sampling, and completes a single sample test in 20 minutes, fully meeting the rapid screening needs of enterprises in industries such as electronics, toys, and medical devices.

1. Introduction
The Restriction of Hazardous Substances (RoHS) directive is a core regulatory framework for environmental protection and human health in the European Union, targeting hazardous substances in electrical and electronic equipment (EEE). On June 4, 2015, the Official Journal of the European Union (OJ) issued RoHS 2.0 (EU) 2015/863, which expanded the restricted substance list by adding four phthalates: Bis(2-ethylhexyl) Phthalate (DEHP), Butyl Benzyl Phthalate (BBP), Dibutyl Phthalate (DBP), and Diisobutyl Phthalate (DIBP) (Table 1). These phthalates are widely used as plasticizers in PVC, coatings, and adhesives in EEE but pose risks of endocrine disruption and reproductive toxicity.

For enterprises exporting to the EU, compliance with RoHS 2.0 requires efficient screening of these four phthalates. Traditional detection methods (e.g., ultrasonic extraction-GC-MS) suffer from drawbacks such as complex pretreatment, long test cycles, and limited applicability to soluble polymers (only 70% of samples). To address these challenges, LISUN Group launched the EDX-4 ROHS 2.0 Test Equipment, which integrates pyrolysis desorption and gas chromatography (GC) to enable rapid, high-throughput screening. This paper details the technical characteristics and performance of this equipment.

2. Materials and Methods

2.1 Key Restricted Phthalates in RoHS 2.0

The four target phthalates and their applications in EEE are summarized in Table 1.

Substance Name	CAS NO.	Main Applications in Electrical and Electronic Equipment
Bis(2-ethylhexyl) Phthalate (DEHP)	117-81-7	Plasticizer for PVC (insulators in cables/wires); electrolyte in ceramics/capacitors
Butyl Benzyl Phthalate (BBP)	85-68-7	Co-plasticizer for PVC (cables, sockets, pipes); additives in paints/glues
Dibutyl Phthalate (DBP)	84-74-2	Plasticizer for PVC flooring; present in synthetic leather, inks, and sealants
Diisobutyl Phthalate (DIBP)	84-69-5	Substitute for DBP; plasticizer for PVC, cellulose resins, and nitrile rubber

2.2 Composition of LISUN EDX-4 ROHS 2.0 Test Equipment

The EDX-4 system is a integrated solution consisting of 12 core components, covering sample pyrolysis, separation, detection, and data analysis (Table 2).

Product Name	Specification Model	Quantity	Remarks
A. Pyrolysis Desorption Instrument	– Ceramic heating module; – User-defined temperature ramping; – PC-side control software; – Deactivation/inerting system	1 SET	EDG version
B. Gas Chromatograph (GC)	– FID (Flame Ionization Detector); – Capillary sampling system; – SSL (Split/Splitless Injection Port)	1 SET	FID detector for high sensitivity
C. Special Chromatographic Column	Imported 15-meter capillary column	1 SET	Simultaneous detection of 4 phthalates
Workstation	One-click test report generation	1 SET	Data processing and reporting
Electronic Balance	Switzerland Precisa 1/10000 balance	1 SET	Sample weighing
4 Kinds of Phthalate Standards	– 4×1mL 1000ppm mixed standards; – Glass bottles + Teflon caps; – Solvent bottle + sealing film	1 SET	Calibration standards
Consumables	– 100 quartz injection tubes; – Quartz sleeves/wool; – N-hexane; – Nitrile gloves/weighing paper	1 SET	Routine operation
High-purity Hydrogen Generator	0-300mL/min, 0.3MPa	1 SET	FID fuel supply
High-purity Air Generator	0-2000mL/min, 0.45MPa	1 SET	FID oxidant supply
Nitrogen Cylinder	99.999% purity + pressure reducing valve	1 SET	Provided by user (carrier gas)
Standard Refrigerator	For standard sample storage	1 SET	Provided by user
Computer	Desktop commercial computer	1 SET	Equipment control

2.3 Technical Specifications of Core Components

2.3.1 Pyrolysis Desorption Instrument

The pyrolysis module is critical for rapid sample vaporization without pretreatment. Its key parameters are:
• Temperature range: Room temperature (RT) to 450°C (1°C increment);
• Heating rate: >500°C/min (Φ6 pyrolysis tube);
• Pyrolysis/purge time: 0.01–99.99 minutes (0.01-minute increment);
• Purge/split flow: 10–200 mL/min;
• Aging/cleaning temperature: RT to 450°C (optional).

2.3.2 Gas Chromatograph (GC)

The GC ensures efficient separation of the four phthalates, with specifications including:
• Temperature control range: Ambient +5°C to 400°C (column oven);
• Ultra-low temperature option: Down to -80°C (for low-boiling substances);
• Gas control: High-precision flowmeter (clear flow visualization);
• Fault diagnosis: Real-time detection for quick troubleshooting;
• Injection system: Split/splitless (flexible for solid/liquid samples).

2.3.3 Flame Ionization Detector (FID)

The FID provides high-sensitivity detection of organic compounds, with parameters:
• Detection limit: ≤5×10⁻¹²g/s (n-hexadecane);
• Baseline noise: ≤6×10⁻¹²A/H;
• Linearity range: ≥10⁵;
• Stabilization time: <0.5 hours;
• Easy disassembly (for nozzle cleaning/replacement).

2.4 Experimental Procedures

2.4.1 Sample Pretreatment

Unlike traditional methods requiring chemical extraction, the EDX-4 system needs no pretreatment:
• For solid samples: Cut ＜5 mg of sample, place it in a 2.5-cm quartz tube, and fix both ends with quartz wool;
• For liquid samples: Inject 1 μL directly into the sampling system.

2.4.2 Analysis Conditions

The optimized conditions for phthalate screening are listed in Table 3, and the retention times of the four phthalates are summarized in Table 4.

Parameter	Setting
Pyrolysis temperature ramping	200°C → 450°C
Micro-pyrolysis time	2 minutes
Sampling method	Split injection
Injection port temperature	250°C
FID detector temperature	300°C
Column oven ramping	50°C (hold 1 min) → 450°C (20°C/min, hold 4 min)
Carrier gas	Nitrogen (99.999% purity)

Substance Name	Abbreviation	Retention Time (min)	Time Window Band (min)
Diisobutyl Phthalate	DIBP	8.524	0.05
Dibutyl Phthalate	DBP	9.041	0.05
Butyl Benzyl Phthalate	BBP	10.941	0.05
Bis(2-ethylhexyl) Phthalate	DEHP	11.949	0.05

3. Results and Discussion

3.1 Standard Curve and Linear Range

To verify linearity, DIBP standard solutions (50, 100, 250, 500, 1000 ppm) were prepared. The peak area (ordinate, A) was plotted against concentration (abscissa, ppm), and the linear equation and correlation coefficient were calculated.
Table 5: Peak Height and Peak Area of DIBP Standard Solutions

Concentration (ppm)	Peak Height (pA)	Peak Area (A)
50	2038.7	8472.5
100	2829.6	12607.7
250	5720.6	24674.0
500	12090.8	53037.4
1000	24747.2	120759.3

The linear equation for DIBP was y = 0.00851004x (y = peak area, x = concentration), with a correlation coefficient (R²) of 0.998023. This indicates an excellent linear relationship between concentration and peak area, meeting the quantitative requirements for screening.

3.2 Detection Limit

The minimum detection limit (MDL) was calculated based on the 3× signal-to-noise ratio (S/N = 3). The MDL for each of the four phthalates was 25 ppm, which is 50% lower than that of traditional PY+GC-MS (50 ppm). This higher sensitivity ensures that the EDX-4 system can detect trace phthalates, avoiding false negatives in compliance testing.

3.3 Repeatability (Precision)

Repeatability was evaluated by testing a 25 ppm DIBP standard solution four times. The relative standard deviation (RSD) of peak height and peak area was calculated to assess precision (Table 6).
Table 6: Repeatability Test Results (25 ppm DIBP)

Test No.	Peak Height (pA)	Peak Area (A)
1	944.8	3484.2
2	1007.3	3638.8
3	903.2	3167.9
4	1205.6	4227.6
RSD (%)	5.24	5.24

The RSD of 5.24% is well below the industry acceptance threshold (RSD < 10%), demonstrating the high precision and stability of the EDX-4 system.

3.4 Chromatographic Separation Performance

The 15-meter special chromatographic column in the EDX-4 system enables complete separation of the four phthalates. The chromatogram of standard mixtures shows four distinct peaks with no overlap, corresponding to DIBP (8.524 min), DBP (9.041 min), BBP (10.941 min), and DEHP (11.949 min). The narrow time window (0.05 min) ensures accurate peak identification, avoiding interference between substances.

4. Typical Application Cases
The EDX-4 ROHS 2.0 Test Equipment is widely used in industries such as electronics, toys, medical devices, and packaging. Four representative application cases are summarized in Table 7.
Table 7: Typical Application Cases of EDX-4 ROHS 2.0 Test Equipment

Case	Industry	Application Scenario	Sampling Method	Detection Item
1	Headphone Manufacturing	Testing PVC green granules for headphone plastic shells (international brand OEM)	Direct solid sampling	4 RoHS phthalates (compliance screening)
2	Mobile Charger Export	Testing white PVC powder in chargers (EU export)	Direct solid sampling	Type Ia phthalates
3	Mobile Phone Production	Testing polymer materials for phone backplates (EU export)	Direct solid sampling	22 phthalates (extended screening)
4	Blind Sample Verification	Customer-prepared mixed standard (4 phthalates)	Direct liquid sampling	Quantitative analysis of 4 phthalates

In all cases, the EDX-4 system completed testing within 20 minutes per sample, with results consistent with reference methods (e.g., GC-MS). This confirms its reliability for enterprise-level compliance screening.

5. Conclusion
The LISUN EDX-4 ROHS 2.0 Test Equipment provides a highly efficient solution for rapid phthalate screening, addressing the limitations of traditional methods. Its key advantages include:
• No chemical pretreatment: Supports direct solid/liquid sampling, simplifying operations and reducing cycle time (20 minutes/sample);
• 100% sample applicability: Compatible with soluble, slightly soluble, and insoluble polymers (vs. 70% for chemical methods);
• Low operational requirements: No professional laboratory or environmental impact assessment is needed (no waste gas/liquid generation);
• Excellent performance: MDL of 25 ppm, R² > 0.998, and RSD = 5.24%, meeting RoHS 2.0 compliance requirements;
• Broad industry application: Suitable for electronics, toys, medical devices, and other fields.

For enterprises aiming to comply with RoHS 2.0, the EDX-4 system is a cost-effective and reliable tool. Detailed product information is available at: https://www.lisungroup.com/products/environmental-test-chamber/5626.html.

Tags：EDX-4